1953 Colchester Student Mk1 6" gap bed - A restoration project





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  1. #1
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    Default 1953 Colchester Student Mk1 6" gap bed - A restoration project

    To start off, a bit of history on this topic. I bought a Colchester Student lathe a few years back for next to nothing and it has not worked a lot as it was super noisy and had a bad vibration when turning.

    A few months back the electrical switch at the back broke and this started a whole exercise to discover the correct switch to find and install. This in turn bred quite a few babies which in the end resulted in me deciding to rip all the electrical wiring out. In turn this exercise bred more babies so now the broken switch replacement exercise has turned into a restoration process.

    This on top of the following other projects I am busy with and have started threads on:



    A few fellow forumites on the AVF asked that I start a thread so that they can lift my arms when these become tired and give some motivation.

    So I decided to copy the thread here for all you guys loving old machines ...

    The lathe's head before I started working on it. It is a roundhead Student with the head being loose and bolted to a V-bed and a gap in the bed between the head and the carriage way section.





    The switch that started it all.





    And what should be in there ....




    I decided to determine what the existing wiring looks like and found this. A replacement contactor hanging by one screw.




    Insulation that simply fell away from the wire.




    Well joined wire to the coolant pump.




    And the straw that broke my patience ... the main wire leading to the on/off switch melted and welded themselves back together ...




    So ... I had enough of shoddy work and I decided to remove all the wiring and electrical equipment ....


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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    I wanted to start this restoration a while ago, but the one thing that stoppped me was that I did not have a C-spanner to unscrew the chuck's holding nut.

    End of last year I set out and asked on the Colchester group on groups.io for help in designing one. The response was quick and some valuable info came forth.

    After some measurements (no not the bar type) and discussions on the group message I had what I needed.




    It is interesting to note that the C-spanner works on friction and not on the front lip gripping. The lip is just to let the spanner lock into place to get the friction grip created.

    I sat down and designed a new spanner on CAD. If you look at the drawing you can see the surfaces where the friction between spanner and nut is created.





    This CAD design I then sent to a local shop to have it laser cut. I had to pay the minimum fee of a full R250 as the actual cost was a lot less than that. Still a bargain compared to buying and shipping one from overseas at a cost of about US$160.

    After a few days I fetched it and deburred the edges. I also noted that the locking lip is in fact rounded at 90 degrees to the length of the spanner to ensure it fits correctly in the slot grinded into the nut.

    Painted a nice red so that I do not loose the spanner.





    A perfect fit! Job well done.





    Onto restoration then as the chuck can now be removed!

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    After stripping out the electrical switchgear panel, I moved onto getting the coolant pump out.

    Low and behold it was secured to the chassis with only one very loose cap screw.




    The ID tag of the pump for anyone interested.




    Onto cleaning the sump. Why is there only oil in there




    Fortunately I love woodworking by hand so I had a BIG pile of shavings available. This is the best method to soak up oil. So into the sump went two giant handfulls of shavings.




    I let it soak overnight and in the morning simply removed the shavings.

    Excellent natural fire starter these shavings!




    A closer look for anyone that has never done this before.





    The sump after wiping with another handful or ten of shavings.





    And cleaned with some turpentine and rags.


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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    So yeah I really had a battle with the lathe the last two days. I could not get the spindle out. More on that in a later post. I think I must sit down now and try and get this thread up to date. Now where did we leave off?

    Oh yeah, switchgear and coolant pump.

    Let me finish off the coolant pump up to where I am now with it.

    The pump sounding like an old helicopter trying to take off when you switched it on, so I knew it had some trouble with its innards. So onto stripping it.

    Off came the lid.

    The underside of the lid was covered with something that resembled bitumen impregnated gauze of about 4mm thick. This to form a seal to the insides. It was all broken up and not sealing at all.





    The wiring connections. Somewhere, sometime in this space-time continuum an electrical wizard decided to replace only a portion of the cable leading to the pump with a short piece of 4-core cabtyre.










    A rock hard rubber boot. Rubber and oil ain't drinking partners ...





    The sieve at the bottom of the pump was blocked so off that came.




    Then the fun started ... removing the bearings. Normally with a electrical motor you have a cylinder in which the stator is housed. Check. End cover on each end. Check. One cover off, one bearing visible? Check. Then support the cylinder and drive the shaft from the bearing housed. Yes ... OK yes but nothing happens ...

    After trying to get the shaft to move from the bearing for two hours, the shaft suddenly moved. Yes, the complete bearing with shaft broke free from the housing when the bottom circlip bent, broke part of the bearing house and sprang loose.








    Quite a number of shimming washers between the top bearing and the top circlip.






    The bearing gave way with a very big puller. It was rusted to the shaft ....





    The bottom bearing came out from the housing as it should.





    Then onto getting the shaft from the bearing. Placing two supports under the bearing and giving the end of the shaft a sharp hit with a bronze hammer did the trick.





    First time I have seen these little corrugated rings fitted between the housing and the outside surface of the bearing.











    A wise gentleman from the groups.io group says that these act as a spring to give way to make the non-self centering bearings align correctly on the shaft. Interesting! Never too old to learn.

    Of interest is that these bearings are in fact metric. Very strange to find metric bearings in a 1953 British made lathe...

    For reference the bearings that were installed are GMN 6200 sealed spindle bearings. The oil seal being a MIS06. Here is a picture of the bearings and the oil seal.






    Removing the oil seal, shows it was not only rock hard, but in fact fractured.



    So my common sense tells me that as the motor would heat up, it would push air out of the housing through the broken seals at each end and when cooling down new humid air will be sucked into the housing allowing the moisture to ingress everywhere inside the housing. I guess I will have to bake the stator as well.





    Onto cleaning the bottom section of the pump. Looks much better.












    Cleaning the shaft, bearing surfaces and rotor worked well with one of those green dishwasher sanding cloths. The electrical connection plate I soaked in @Family_Dog's favourite drink.





    Cleaning the top surface of the housing ...





    ... and it revealed it was hit by a hammer in it's past life! I sanded it down on 250 grit wet paper glued to a pane of 6mm glass to get rid of most of the dings. This is good enough to get a seal again.





    That is how far I got with the pump. Now onto getting the paint off the housing and the top cover and spray everything with an oil proof epoxy paint.

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Next portion to cover to get this thread up to date is the electrical wiring and panel.

    I could not figure out how the electrical circuit works as my lathe did not have the original switch fitted (refer above) and what I could see did not make any sense.

    So back to the group I went. Another kind gentleman, Richard, had the same issue during restoration of his Colchester Student lathe. You can read his struggles here. Between him and the gentleman helping him, Phil, I could start to understand what is what.

    Apparently the switch is a no-voltage limit switch and together with the contactor forms a circuit where the lathe cannot start again when the power supply goes down whilst the stop/start handle is in the "ON" position. You manually have to move the handle back to "OFF" and then back to "ON" to get the lathe to run again after the power supply is restored.

    As per Phil's hand drawn diagram,





    which is based on either of these two wiring diagrams







    the switch works as follows:

    "Refering to the drawing you will see what we call the limit switch (because that is what it says on the case) is referred to as the Craig and Derricot release switch.

    Starting at the contactor coil, you will see that one side of the coil is connected to L1 which is an incoming phase. Remeber that the coil works between two phases, there is no neutral in this set up!

    The other side of the coil connects to terminal 2 on the contactor, and then to the red wire which goes to the C&D switch terminal 3.

    The other phase used is L3 which goes via a link wire through terminals 10 and 9 on the contactor, which are the overload cut out switches, and then on through the yellow wire from terminal 9, through the end cover and lock switches to terminal 1 on the C&D switch. Note a mistake on the drawing, in that the yellow and red wires which cross adjacent to terminal 3 on the C&D switch are NOT connected but the semicircle has been ommitted from the drawing!

    When the end cover is fitted, and the key switch is on, terminal one, yellow wire on the C&D switch is "live".

    When the switch is lifted from the off position to the intermediate position, (we will call the unmarked terminal on the C&D switch 4) 1 and 4 are connected together, and 2 and 3 remain connected. the live goes from1 to 4, down the link to terminal 2 across the switch to 3 and back to the coil on the red wire, and the contactor pulls in/motor starts.

    on the contactor, the holding in contacts close the circuit between 1 and 2, and as the start handle is moved fully in to the on position, the C&D switch opens 2 and 3, and 1 and 4 remain closed. Machine is now running, and terminals 1 and 4 on the C&D switch have become part of the holding in circuit and the machine will continue to run till the contact is broken by pushing the lever to stop, or if the power fails, the end cover is removed, or the key switch is turned off."


    Wow, I thought to myself, let me really understand this. So I spent an hour doing my own diagram of the description. Obviously in those yonder years, a contactor and a switch was an expensive item so the designers had to make do with as a smart design working on limited equipment. Well, their logic and method works fine. Just not the way we would do it today with our cheaper and much more efficient and effective switchgear.

    OK, I understood the logic now, but I had no idea the lathe had the two switches as stated in the description and the wiring diagram. So I asked a few questions and was directed as to where I must look. Lo and behold I found them. I really had to scrape a lot of gunk away!

    The key switch at the tailstock end in the upper back corner of the drawer.





    No, there is not a key like you will recognise today. It is a simple cupboard type lock with the hollow shaft key!






    The switch model and type.





    The cover switch was even more obscure to find. Find it I did as I was determined ...

    It is here somewhere ...





    Almost there ...





    Gottit





    I would never have thought to look there!








    And a close up of the cover switch.





    So that is the switching circuit sorted out. Onto getting the wiring panel stripped and cleaned.

    The panel connects to the lathe's supply circuit with a three prong plug as seen at the bottom of this earlier posted photo.







    It appears that the panel was wired by a third party and then simply plugged into the lathe.






    The female socket mounted inside the lathe and made from Bakelite or some form of organic cellulose sheets.






    The "new" contactor is a Telemechanique and it looked like it can still function after a good clean.







    Aaah ... fuses!









    The one fuse contacts were spark eroded, so I cleaned it up and soldered a new surface to it.







    ... and promptly lost it somewhere in my workshop when it went flying from my hand ... find it I will.


    The coolant pump switch on the left and the ON/OFF/REVERSE main switch on the right. Massive three phase switches made from bakelite.









    All stripped from the cast aluminium panel.







    Electrical switches and fuses went into @Family_Dog's favourite drink and I left them there for four hours. Came out very clean and the brass even was sparky .. I mean sparkling ...







    All cleaned and waiting to be assembled.





    To get the main switch's selector handle off was a mission. Some monkey snapped the locking machine screw in this handle and it broke in two, lodged secure at an angle in the handle. I had to break the handle to get to the screw and then remove it.





    I made a thread here on how to repair it.

    Well, this is as far as I got with the electrical wiring and logic. My next step was to determine the status of the main bearings of the lathe as these would dictate if it is worth the while (and money) to fix the lathe. More later in a next posting ...

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Before I start restoring, I wanted to understand why the headstock was filled with grease and why at high speed it was so noisy. Maybe something expensive needs to be replaced which will make this whole exercise fruitless and not worth the money.

    So ... bring it on grease monkey.

    First step normally is to remove the side cover. Check. Did that a few days back and battled to get it off as the standoffs it is fastened to are bent. Remember it is cast something so no hammering!

    Then onto removing the drive belts. These must be a matched set. The belts are the same size, but that does not help anything in this type of installation.








    I could not find any markings stating that the two V-belts are a matched pair so that explains the vibration in the drive train. In non-matched pairs one belt is always longer than the other and will hunt will turning causing a vibration. For this reason I always use Nu-T belts. A lot more expensive but lasts forever and does not care about the condition of the pulley's groove.





    OK, this is turning into a nightmare ... the belts cannot be replaces without removing the drive pulley ...





    This means I need to get to the electrical motor and get that slacked off and then remove the drive pulley. First step is to move the lathe away from the wall. Now ... because I threw or gave away all my odds and ends with the planned move to NZ, this included my roller set. OK, I managed to find three short pieces of 3/4" pipes and with two wedges and a crowbar I managed to move the lathe enough so that I could get to the electrical motor.





    Now for the motor experience ...

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Man, I am way behind on my postings here vs the progress on the lathe. Let me jot down some more if my fun ..

    Yes, the motor.

    It is a three phase (380VAC) 2,2kW motor.






    The motor is mounted on a plate that swivels on a bar and is locked into position by two bolts, one on either side of the plate.









    The left hand side's bolt (yes, LH looking from the front of the lathe) was missing. This is on the tension side of the plate, so this will mean that the belts were only tensioned under the weight of the motor!






    The connector panel. The wires from the switches to these pins were mixed and not according to the phase numbers as on the motor's wires.









    I removed all the wires, the spiral conduits and fittings. For now the motor can sit and watch me work. It will get it's turn to be fixed.

    Onto getting the V-belts off.

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    With the motor plate wedged and the belt tension relieved my helper Carl and I could remove the pulley assembly. The pulley assembly is actually also the brake system's drum. We had to use a puller to get it off, but once moving it came off easily.

    Man, it is full of oil so that is not good. It means no brake effect and a leaking oil seal (which in this case will be a leather washer acting as a seal).







    Just for interest sake Carl is one of those rare persons in the world that loves getting his hands dirty and stays calm doing so. He was a steam locomotive driver and a good one at that. I can listen to his stories for ever. Steam engines stir my heart since I can remember and to chat each day with a guy who knows all their ins and outs is simply an honour.

    Back from the steam era to reality of restoring a lathe from that same era. Weird ...

    Talking of weird ... the drum brake shoes have no lining!?? Does this work as metal on metal?









    The brake shoes which is made as a single steel unit!





    The wedging mechanism at the bottom of the shoe system. It gets pulled down by the ON/OFF selector switch handle at the front of the lathe.





    The wedge that forces the shoe system open.







    Next step was to remove the brake system flange and drive spindle. I wedged it with three hard wood wedges between the back of the flange and the headstock's external surface. A few taps on the wedge ends it it came of easily. No gaskets are to be found.







    The leather seal looks old and well worn. It has the number 1621 stamped on it. Maybe someone can tell me what the modern day equivalent seal number will be? Otherwise I will have to take measurements and hunt it down on the Timken seal selector tool.







    Next step is to remove the change gears. Now it is time to light a fire and relax.

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    An interesting comment I received: "Jussus so this thing was serviced by a brutish oaf with a sideline as a butcher? With that machine's sorry history, I wonder if those curious metric bearings were because someone needed to replace them, couldn't be arsed to get original imperial ones and just dondered the closest off-the-shelf ones he could find"

    So the Brutish Butcher was born ...

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Next step was to remove the change or screw cutting gears.

    These gears can be changed to create different threads in conjuction with the screw cutting gearbox.

    The three gears lined up.





    And the next surprise ... look at the large gear and then at 12 o'clock.





    A tooth was snapped off. At this stage I had no idea why the tooth could have been snapped off ...

    Oh well, onto removing the gears. These are held in place with a knurled nut that can be gripped by hand and turned loose. Not in this case. I had to get a water pump plier and really put effort into getting the nuts loose.





    The top gear of the set removed. Is it a 109 tooth gear as the stamp indicates or is it a 60T stamp? Someone please count the teeth and let me know if one is missing.







    Onto removing the swing frame that is located behind the large gear. The adjustment locking nut has seen better days.





    Removing the top gear revealed an astonishing fact. In this gear there is a shear pin. You all know (or should know) what a shear pin is. It is a pin designed to shear through when something in the drivetrain or operational side gets stuck. It is like a mechanical fuse and needs to be rated to the mechanical power of the lathe to allow normal operation, but be cut by the shearing action of the gear it fits into when the gear wants to turn, but something bad downstream has happened.

    My first view of the shear pin.





    Wow that looks odd was my first impression. It looks too small for the hole and it looks like it is bent! On removal, my heart sank into my shoes.





    I could not believe what I saw ... anyone recognises the piece of metal? Come on ...

    It is the end of a 1/4" drill bit!





    This is bad. To bend a drill bit shank like that it means something went very wrong on the lathe and the power had to go somewhere and something had to give. You can guess what gave way.

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Time to move onto the headstock that has been filled with grease. Why anybody does that goes beyond any rational logic. Maybe they worked for the government?

    The headstock was designed to be lubricated by oil having little sumps with oil holes feeding the shafts, bushes and bearings. With grease no lubrication can get into the bushes or bearings ... nuff said.

    Anyway, let's get cracking. Because we removed the driveshaft we could remove the two speed selection gears. What a mess the grease creates.








    Next step is to remove the spindle and the other shafts. Whichever can be removed will come out. I have no manual for this lathe as the existing manuals available does not cover it. Only hints here and there as to what is what. So it is literally feeling my way in the grease ...

    So onto the spindle as this is the uppermost part I can reach.

    First step is to take the chuck off. Fortunately I have a brand new C-spanner that has been waiting in the winds ... it took quite a few hammer hits on the locking nut while holding the nut under tension with the spanner to get it to release. I used supporting wooden blocks under the chuck as I am sure no safety boot will prevent that monster from crushing my toes when it starts rolling.








    The nut, the L0 cone and the backplate with thread onto which the nut screws.





    Next in line were the two standoffs. These came off with some trouble as the threaded section on one side was severely bent. I will have to turn new ones I think.







    The drive side of the spindle has a lock nut screwed into it and locked in place with a grub screw. On the outside face of the headstock is what appears to be a covering flange ring of the main bearing. For no reason at all except that it looked easier, I removed the flange first. First step is to clean the cap screw holes with a engineering scribe (OK yes, it is not designed for that, but it works great). A few knocks with a nylon lead shot hammer and the flange cracked from the headstock face and I could pull it away using a thin wedge of hard wood.







    Then onto removing the grub screw and undoing the nut.





    All done and nothing left to remove on the external bit of the drive side of the spindle.







    So that is the drive side done. Next up is the chuck side. What do we have here?





    A flange nut that screws up against an inner bearing flange. Obviously to get the correct shaft play and maybe bearing pressure created.





    I do not have the correct C-spanner to remove the nut. In addition someone really damaged the slots with a punch, so I decided I can do the same for now and repair the damage later. So out came the grub screw and a few taps later the nut unscrewed onto the spindle.

    Now the manual states that you need to protect the end of the spindle on the drive side and hit it with a big hammer and the spindle will slide out on the chuck side. Well here the fun started .... two hits and the hammer sound when hitting changes to hitting against something solid. OK, let me try hitting on the L0 taper end. It moves back for about 8mm and then the sound changes to solid again.

    Now, hitting against cast iron will most definitely cause it to shatter. So I stopped. Something is wrong somewhere. Back to the drawing board or internet for info I went. I asked a few questions on the groups.io site and read a very similar posting on Model Engineer. The only problem is that nobody has ever seen a spindle and headstock like this one and no advice was forthcoming.

    When hitting [pun not intended but it is there] an issue like this the best is to sleep over it. So a night later, I went back and look at the scenario. Richard in his thread states that he could unscrew the cap screws holding the external flange in place through a deeper recess in the chuck's nut. Well, this nut had no deep recess and there was no visible cap screw heads visible, nor any space to work in.






    So that solution ain't going make any kite fly. Not that it was a windy day in any case ... So, time to step back; wish I had a beer to drink and had one more coffee. I pondered on it the whole day, my mind working out all possible scenarios as to how the whole thing is assembled. Looking down the spindle it appears that the taper cone is screwed onto the spindle.







    With the help of a mate of mine we tried to loosen the cone. The only thing I achieved was to wreck the key in the cone. These old lathes really has some very soft steel in their parts! OK, another wish for a beer and my mate left as we could not do the mate thing ... This lockdown prohibition is not good for friendship times.

    Onto finding why I hear the solid sound when hitting the spindle. OK, I thought maybe the spindle gears are stuck against the gears below it.





    So I decided to remove the shaft below the spindle to get the gears to drop down. Remember no manuals, no knowledge as what to do and almost at my wit's end.

    Out came the grub screw.





    And out came the shaft. No issues here.







    And drop the gear did.





    And the solid sound once again shattered my hopes ...

    Another night's sleep and then I thought that I only have one option left. I know there are cap screws on the inside of the headstock. I did screw one out and it was a short one and hence can only hold the inside flange. So ... what is holding the external flange in place? A few photos later, it seems that three cap screw ends are visible in the holes of the external flange.





    Counting the cap screws located in the inside flange I found six. Yeah, lady luck pulled a fast one on me when I unscrewed the first cap screw. Undoing the next one, it turned out to be a long one, fastening both the inner and external flange! Great, great news. So I promptly undid the cap screw I could see and then hit the greasy mire again ... somewhere down there, should be more hidden cap screws. Digging out the grease if found them below the spindle with almost zero access.





    A standard Whitworth key from Uncle Allen did not work. No place to turn it... Stuff this I thought let me make a plan. So I cut the end off one key, took a No5,5 socket from my 1/4 drive set and stuck these onto the miniature ratchet set I have.





    And it worked on the first hidden grub screw.





    Another cup of coffee for energy, hope, dreams and just a caffeine rush, I tackled the worst cap screw.





    After about 30 minutes I managed to unscrew the cap screw far enough so that I could not remove the miniature ratched wrench assembly. The back of the ratchet pressed against the gear before the end of the key cleared the cap screw's hole. Now I really needed a drink ...

    So I called the Boss to come and speak nice words to me and hold the lead light while I try to flick the ratchets direction lever with the hook end of the engineering scribe. That is the only thing that could reach there. I had to work on feeling as it is not possible to see anything. One full hour later, the lead light holding itself in place because the Boss left after learning too many new words, the cap screw was out!!

    Alas, the end was not in sight! This mean little grub screw had it's drive end shattered by the Brutish Butcher.





    Stuff that Britt I thought and hammered a spline key into it. With a load click it sprang loose.





    Out came the hammer and block of wood and two hits later the spindle with bearing securely fastened to it, popped out!





    I quickly checked the drive side end as the manual states that there are bearing springs that can jump out. Nope the manual is wrong ... there are no springs. Only an unknown, unmentioned toffee (or should that be grease?) coloured horisontal thrust bearing.





    Oh well, then let me keep driving the spindle out. Wow, a horisontal roller bearing ... no taper roller thrust bearing?





    I will ask on the internet about this later I thought and gave the spindle a last hit and pulled her free!





    All the gears and bearings laying quietly in sequence in a grease bedding as if nothing happened during the last two days ... sounds almost like a baby.





    A better view of the horisontal thrust bearing.





    Well, by this time it was evening again and I called it a day. Tomorrow will hold new challenges and things to discover!

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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    A quick note that is important.

    Each of the two threaded collar found on the spindle is held in place by a grub screw. It is important to note that inside the grub screw hole and found at the very bottom edge of the hole is a small little brass plate. This plate serves to protect the thread on the spindle from being deformed by the grub screw.







    It fits here in the threaded collar's grub screw hole.


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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Time to remove the spindle gears.





    And they are gone ...





    I built a wooden box for all the gears to be stored in. I know the Boss will annex it when I am done with the project and paint it some hippy colours.





    The spindle gears waiting to be cleaned. I used an aluminium tube to act as a temporary spindle for easy of cleaning.





    Two views of the spindle bearing at the drive end. It turns out this is an angular contact ball bearing that acts as a taper bearing.






    I will jot down the bearing numbers in the next posting for future reference. It is quite interesting for me that nobody else in the world of Colchester lathes (OK that is on all the groups and forums where I asked) knows about a Colchester lathe with a off-set thrust bearing plus a horisontal thrust bearing on the drive side and then a flat roller bearing on the chuck side. A comment was made that maybe this is a carry over from the 1940's Master headstock design. Let me know if you can cast some light on this design and where else it was used in the Colchester range of lathes.

  19. #14
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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    For future reference.

    The headstock bearings are as follows from Left (drive side) to Right (chuck side):

    1) Angular contact ball thrust bearing: Hoffmann 150AC
    2) Horisontal thrust race bearing: Hoffmann LM50
    3) Tapered double roller bearing: SKF NN3012XK-SP

    Specifications of each are as follows:

    1) Hoffmann 150AC
    Inside Diameter : 50 mm,1.9685 in
    Outside Diameter : 90 mm,3.5433 in
    Radius : 0 mm,0 in
    Width : 20 mm,0.7874 in
    Model: 150ACD
    Classes: BALL BEARING
    Details:SINGLE ROW, ANGULAR CONTACT

    2) Hoffmann LM50
    Inside Diameter : 50 mm,1.9685 in
    Outside Diameter : 78 mm,3.0709 in
    Radius : 0 mm,0 in
    Width : 22 mm,0.8661 in
    Model: LM50
    Classes: BALL BEARING
    Details:SINGLE ROW, 3 PIECE THRUST
    Other Details:WITH GROOVED RACES

    3) SKF NN3012XK-SP
    Inside Diameter: 60 mm
    Outside Diameter: 90 mm
    Radius:
    Width: 26 mm

    Still trying to find the final details of this. It is a NN bearing with code 09 inner race taper ... maybe someone can help out.

  20. #15
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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    The last thing to remove on the spindle set was the inner flange.




    I did not want to try and punch it from outside nor pulling it. So I screwed in some of the cap screws and located a flat bar between the protruding cap screw shafts and gave it a bit of a turn. It came out very easily.





    And you can see the SKF bearing's external ring in place.





    Onto removing the rest of the shafts. All locked in place with a grub screw on a gear, nut or flange. Not difficult.





    All of the shafts are running in bronze bushes. I had a bit of chat as to how to remake these on groups.io and a comment was made that the oiling spiral groove would be difficult to make. A quick looksee showed that this spiral is actually machined into each shaft and not in the bush. The bush has a smooth inner surface.







    How the oil gets into the bush was still a mystery so I had a look at what could be found at the top of each bearing. Just grease ... yeah OK, someone loved grease ...





    I spent some time clearing the grease away with my magic wand ... wish wish and a neat little sump appeared.





    and with some more magic wand waving ... (you get the picture)





    A drain hole in each sump that corresponds to a hole in the bush. Also in the sump is a grub screw that locks the bush into position.





    Now how our friendly Brutish Butcher thought grease is going to flow into the sump and then down the little hole into the bush, I have no idea. Maybe he was of the opinion that once the bush heats up the grease will melt and quickly run down and cool the bush. Yes, maybe in another space dimension.

    Once all the shafts were removed, I removed the grub screw of each bush and using an aluminium drive hit the bushes out. They came out quite easily if you drive from the inside outwards.








    At this time Carl called me. He has just cleaned one of the speed selector gears. Not good news.





    More missing teeth! No beer, so more coffee ...

    OK, lets move on. We will sort the tooth fairy out later ...

    The front reverse lever was next to be removed. The handle slides off after removing the cover dome washer secured with a cap screw.




    At the very inner end of the shaft it has a pin that fits into a funny bronze rectangular piece that slides in the gear and moves it. Can you see it? Neither did I ... it is there somewhere in the Butcher's fat.




    Take care to remove it and keep it with the same gear. No, do not ask me how I know this little piece of info. Good news! The mystery washer found its place later on.





    A gentle pull on the handle with a hammer (yes hammers are excellent pullers as well!) the shaft came out and revealed a thick leather washer that fits between the inside face of the headstock wall and the shaft's flange.









    Next step, removing the front speed selector handle and shaft. There is a nyloc nut on the end of the shaft that you need to undo with a 7/16" AF spanner.







    Then you simply pull the gear off. You pull ... and pull and nothing happens. OK, what now. No beer, more coffee and pondering ...

    more pondering ... and then stuff this. Let's move onto something else to remove. I will cover this later on and jump forward in time. Next day.

    I remembered that Richard made mention in his thread that he removed this gear and replaced the leaking leather seal. So I asked him how he managed to get the stickler off the shaft. He donated some knuckle skin and blood was his answer but in the end it came off. Well, I am not into self flagellation with gears so I had some more coffee and an apple and slept on it.

    Next day, while Carl was cleaning and using all of my bale of waste rags to get the Brutish fat out of the headstock, I set out to make a gear puller. The issue is that there is not a lot of space to work with and I could not take up any movement of the gear with the turning screw. I had to do this with the legs and then with the thingies that grip the gear. I ended up using long hex nuts on thread bar, a 8,8 grade bolt cut to length, some 5mm nuts and a hose clamp.





    I put some tension on the bolt and nothing happened. OK, now I will force you. Oh you will? I will bend just to show you how stuck this gear is!





    Out came the copper hammer and I gave the gear a few smacks while putting tension on the bolt and praying that the bar does not bent any further. With a torturous creak, the gear moved. The Brutish Butcher was involved here!

    After one hour of tightening the bolt, loosening the bolt, adjusting the long nuts and repeating the process, the gear was almost free.





    And done. Note the leather washer. It was rotten.





    Well, not ... there is a little piece of metal peeking out from the shaft. My pet hate when it comes to shafts.





    This one was stuck. I mean like really stuck. It did not want to move even when punched on any end.

    So I resolved to violence. Something we have learned to live with in this beautiful country of ours. Out came the nail extraction pliers (or as we call them in my home language "knyptang" ... loosely translated as "the pinching pliers").






    I managed the move the little Woodruff key but it did not want to come free. It took me another hour to get the key removed from the shaft. It was really hammered out of shape with the top flat section having a ridge bending over the side.






    At last! I could remove the handle and shaft combo. I wanted to know why I had this battle to get a simple gear removed from a shaft. I therefore decided to clean the shaft and see what is what in the world of shafts and stuck gears.

    Brass wire wheeled and clean.





    The gear has hammer marks on the end!!






    The Brutish Butcher was here!

    The gear would only slide so far onto the shaft.





    The shaft showed some hammer dings. OK, not so visible in the photo, but it raised the ding edges quite a lot from the surface.





    It was Sunday and I did not have any Engineering Blue. I had no beer, but coffee. Off to the coffee machine I went and pondered on what to do. I have given away all my pens, markers etc for the move to NZ ... aha I still had an stamp inking pad! I rolled the shaft on the pad and gave it some time to dry.





    Onto checking what the gear and the shafts' mating problem is. Almost sounds like a farmer with his prize bull not wanting to do anything with Daisy.






    Yes, the gear was oval. When it did not want to fit onto the shaft our Brutish Butcher obviously decided to thunder (OK that is a direct and grammatically wrong translation of an Afrikaans word meaning to hit something very severely) the gear onto the shaft. Hence the marks on the end of the gear and the squeaking sounds when I pulled it off. "Squeaking squirrel" always comes to mind when I hear the word squeaking ...

    So by now you know I had no beer to ponder over. This time I made some Rooibos tea with honey and lemon for inner healing and peace.

    After three hours of filing and polishing I had a gear that looked fairly new, could slide easily over the full length of the shaft and a polished Woodruff key that did fit correctly.





    The moral of this story? No, not to have enough beers! The key to success is a soft touch.

    Time to move back into time ...

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  22. #16
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    Thumbs up Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    What a fascinating project. It's obviously a labour of love as you persist even when it seems so much of it is worn to bits. Thanks for posting in such an easy to follow style. So it looked like a butcher had overhauled it before with all those hammer marks. I couldn't help but wonder about all the things that this lathe must have turned out over the years and wether any of those things survive today. I'll keep an eye out for your updates.

  23. #17
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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Awesome Mygoggie, brilliant project, please keep posting!!

    Cannot understand the grease phenomenon..!!
    Every dog has its day, and those with broken tails have their weak-ends...

    1976 CJ-7, 400CI + Holley EFI, Tera-Low 3,15:1 twin stick, ARB's front & rear, oil leaks & plenty more....

    All my other petrol burners are boring....

  24. #18
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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Wow, amazing. Thanks for taking the time to share this with us.

    Iím still trying to get my hands on a Myford or Boxford at a reasonable price but not having much luck at the moment.
    4.0 XJ Jeep Cherokee - Go anywhere
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  25. #19
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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    This is awesome! Thanks for posting this, i enjoy it, and admire your patience!

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  27. #20
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    Default Re: 1953 Colchester Student Mk1 6" gap bed - A restoration project

    Beautiful to see! The fact that you can take it to pieces and then put it all back together again is what is really a skill that is scarce nowadays.

    It's really sad that nobody fixes anything nowadays. Throw it away and buy a new one!

    Can't wait to see the video of it working again.

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