White metal casting for restoration

[Peter Connan]

Theres nothing in my workshop that can measure to 0.0025mm..I wonder if this couldnt be done in a lathe using a very course thread.Or how is rifling done in a rifle barrel.?

Mygoggie, sorry for deliberately taking your thread off topic.

Plunger, rifling is don in one of three ways. It can be cut, buttoned or hammer forged.
Hammer forging uses a former which looks somewhat like a very long bullet would look at the moment it comes out of the barrel and before it runs into a concrete wall. This is inserted into a thick-walled tube with a inside diameter slightly larger than the final size, and this tube is then hammered down onto the former. Clearly not suitable for this purpose.
Button rifling is formed by using a similar former to hammer-forging (but typically ground from Tungsten Carbide) which is forced through a slightly smaller ID tube, often by hydraulic pressure. Again, not going to help here.

The above two methods are currently the most common as although the machines are expensive, they are the most suited to mass production.

Lastly, there is cut rifling, which can be divided into two sub-methods, the first being broaching and the second single-point cutting.
This final one is the only one which can conceivably be used for this purpose, but even that is unlikely. I actually own a single-point rifling machine (the first machine used in this country to manufacture barrels). Imagine a lathe with the head and tail stocks fixed, and a chuck mounted on the carriage in such a way that it is rotated by a rack which is connected to the taper-turning attachment. The carriage is hand-powered, and when it moves, the chuck turns at a speed proportional to the movement. The tool (shown in the attached picture) is stationary, held in the headstock via a long rod and is guided by the barrel, the cutting depth can be adjusted by a hand-wheel on the tail stock.
As you can imagine though, such a machine cannot achieve the angle/pitch required for this job.

Obviously there are much more modern options, but the only company I know of currently making barrels in SA is Truvelo Manufacturing, who as far as I know use the button method, and possibly also hammer-forging now.

[Peter Connan]

Mygoggie, were it me, a cerfully-shaped block of wood attached just ahead of the cutting edge...

[mygoggie]

Mygoggie, sorry for deliberately taking your thread off topic.

Plunger, rifling is don in one of three ways. It can be cut, buttoned or hammer forged.
Hammer forging uses a former which looks somewhat like a very long bullet would look at the moment it comes out of the barrel and before it runs into a concrete wall. This is inserted into a thick-walled tube with a inside diameter slightly larger than the final size, and this tube is then hammered down onto the former. Clearly not suitable for this purpose.
Button rifling is formed by using a similar former to hammer-forging (but typically ground from Tungsten Carbide) which is forced through a slightly smaller ID tube, often by hydraulic pressure. Again, not going to help here.

The above two methods are currently the most common as although the machines are expensive, they are the most suited to mass production.

Lastly, there is cut rifling, which can be divided into two sub-methods, the first being broaching and the second single-point cutting.
This final one is the only one which can conceivably be used for this purpose, but even that is unlikely. I actually own a single-point rifling machine (the first machine used in this country to manufacture barrels). Imagine a lathe with the head and tail stocks fixed, and a chuck mounted on the carriage in such a way that it is rotated by a rack which is connected to the taper-turning attachment. The carriage is hand-powered, and when it moves, the chuck turns at a speed proportional to the movement. The tool (shown in the attached picture) is stationary, held in the headstock via a long rod and is guided by the barrel, the cutting depth can be adjusted by a hand-wheel on the tail stock.
As you can imagine though, such a machine cannot achieve the angle/pitch required for this job.

Obviously there are much more modern options, but the only company I know of currently making barrels in SA is Truvelo Manufacturing, who as far as I know use the button method, and possibly also hammer-forging now.

This is very interesting. Thanks for sharing this information @Peter Connan!

[mygoggie]

Mygoggie, were it me, a cerfully-shaped block of wood attached just ahead of the cutting edge...

Great minds think alike. This is exactly what I am planning to do.

[Peter Connan]

I like the concept, but considering that the cut's pitch needs to be closer to radial than axial, perhaps a large and nicely-machined dowel (that fits exactly inside the bush) with a T-handle, with the cutter being of round section (so that it can be rotated to be square with the cut direction) and a "pocket" for chip evacuation?

[mygoggie]

I like the concept, but considering that the cut's pitch needs to be closer to radial than axial, perhaps a large and nicely-machined dowel (that fits exactly inside the bush) with a T-handle, with the cutter being of round section (so that it can be rotated to be square with the cut direction) and a "pocket" for chip evacuation?

Sketch this for me if you do not mind.

Nicely machine by hand it will have to be ... aziko lathe apha

Just as a reminder this is what I need to cut ...

[mygoggie]

This is the way to do it if you have a lathe ...

[Peter Connan]

Interesting gizmo.

Does.this help?

Last one os the cutter.

[plunger]

What would happen if you did a groove where the oil hole is and an oil groove on both ends of the bush and then join them with grooves that run from the oil groove hole longitudinally to meet the three round grooves you have machined . I would think it would work and would be simple to do using a radius tool for o rings and using the rack as a shaper.

This would be simple on cnc. I would use a die grinder and carbide 1/8 burr for a one off. I wonder what the biggest diametrical pitch you can get on a manual lathe.

[mygoggie]

What would happen if you did a groove where the oil hole is and an oil groove on both ends of the bush and then join them with grooves that run from the oil groove hole longitudinally to meet the three round grooves you have machined . I would think it would work and would be simple to do using a radius tool for o rings and using the rack as a shaper.

This would be simple on cnc. I would use a die grinder and carbide 1/8 burr for a one off. I wonder what the biggest diametrical pitch you can get on a manual lathe.

Yep, that is the last resort way I will do it as I know it will work. How good is the question. Been sitting this afternoon thinking of to do it and it is not that simple ... But ... I have Brain on my side

[mygoggie]

Interesting gizmo.

Does.this help?

Last one os the cutter.

That was my original idea. Issue is how to you start the slot as it only comes to the edge on one leg. Secondly how to you keep it on track. You either need an external guide or eyes on a line.

[Peter Connan]

An external guide should be pretty easy. Maybe as simple as a triangular-shaped sheet of transparancy taped to the outside of the housing?

As for the single entry, that makes it considerably trickier.
Perhaps a tapered screw (think of an idling jet from a carb) screwing in from the back end allowing you to adjust the tool out?

But if a CNC mill is available, a ball-end cutter (possibly a router bit as I haven't seen one for steel), circular intorpolation and the bush mounted vertically migyt be the easiest option?

[Landy90fan]

Great minds think alike. This is exactly what I am planning to do.

Aaah this takes me back - using scrapers like that to bed in big winder bearings (+350 mm shafts) with Engineers Blue...recall the metal was Hoyts No. 11.....

[Peter Connan]

Mygoggie, my thinking aparatus is not as refined as Brain, but it does it's best work when given some time to ruminate.

It has come up with the following overnight:
I don't think the depth of the groove is critical, except where iteaves the bushing. Thus, the ideal (if doing it by hand) would he to start at the hole.
I now think the tool as drawn by me, but with the body made from a longer piece of thinner (let's say 25mm diameter) well-finished steel, long enough to protrude through the bearing housing on both sides far enough to get a grip), and with the cutter mounted square might be the answer. Perhaps also a couple of small holes strategically placed for "pointers" to align with the edge of the transparent guide discussed earlier?

Whatever methods and tools, I would practice on some PVC pipe. That will be much more difficult than white metal, so a good test.

[mygoggie]

Mygoggie, my thinking aparatus is not as refined as Brain, but it does it's best work when given some time to ruminate.

It has come up with the following overnight:
I don't think the depth of the groove is critical, except where iteaves the bushing. Thus, the ideal (if doing it by hand) would he to start at the hole.
I now think the tool as drawn by me, but with the body made from a longer piece of thinner (let's say 25mm diameter) well-finished steel, long enough to protrude through the bearing housing on both sides far enough to get a grip), and with the cutter mounted square might be the answer. Perhaps also a couple of small holes strategically placed for "pointers" to align with the edge of the transparent guide discussed earlier?

Whatever methods and tools, I would practice on some PVC pipe. That will be much more difficult than white metal, so a good test.

Brain is super excited! He ran off to his books to look up for the meaning of "ruminate". I think for the next few days I will hear all about how you can use this word in all the various possible combinations and permutations in the English language.

Yes, I am in agreement that the correct point to start cutting is at the hole.

However I am a bit guilty and have not shared the current status with you. The bush is already mounted and machined to size in the housing. The groove cannot be cut beforehand and can only be done once the press fit and machining to diameter has been done. This means that rear access from inside the housing is rather restricted. My hands are too big ...

I played a bit yesterday with some masking tape and a stick with a paperclip through it to see what is what and I will need a guide on the outside of some sorts. The spokeshave setup as you suggested is what I figured out as well. I like your idea of the round chisel combined with an idea from @Tzs503gp on the AVF forum to first cut a very narrow guiding slot/groove.

Practicing on the uPVC is a very good idea. Thanks for this.

[mygoggie]

I worked the whole day on the Pajero's transfer case so only had time to post now.

Here is the extension housing with the bush installed.







So whatever I do will have to be done with a round bar that goes all the way through whilst the housing is clamped in some form of jig or holder. The view angle into the bush is very limited so that is why I am thinking of making an external guide. Brain is still busy with the new word ... no help from his side ... sigh ...

[mygoggie]

I found this very interesting thread.

How to cut an internal helical oil groove

Seems like the simplest way is by hand in a Dremel tool which will not work here as I have so little thickness to work with. The other option is to use a helix slotted pipe as a guide. Maybe a large drill bit could work ... I will check tomorrow. Now too tired to think straight.

[plunger]

I found this very interesting thread.

How to cut an internal helical oil groove

Seems like the simplest way is by hand in a Dremel tool which will not work here as I have so little thickness to work with. The other option is to use a helix slotted pipe as a guide. Maybe a large drill bit could work ... I will check tomorrow. Now too tired to think straight.

Mygoggie that site you posted about the helical groove can be very helpful. I had a worm and wheel gear that stripped in my vertical bandsaw . With there help and a CAD drawing done by a member after giving him dimensions I was able to machine a new worm and wheel gear.
I have already posted your question about making this bush on it as early as January. You will enjoy this site and when your lathe is up and running would probably learn a lot from the guys on this site.
Why dont you just take over the thread from where I started.I had a need to make two white metal bushes and that is why I was curious. This was to fix a jackshaft on a southbend lathe. But for now vesconite is doing the job.

https://bbs.homeshopmachinist.net/fo...w-to-make-this

[mygoggie]

Mygoggie that site you posted about the helical groove can be very helpful. I had a worm and wheel gear that stripped in my vertical bandsaw . With there help and a CAD drawing done by a member after giving him dimensions I was able to machine a new worm and wheel gear.
I have already posted your question about making this bush on it as early as January. You will enjoy this site and when your lathe is up and running would probably learn a lot from the guys on this site.
Why dont you just take over the thread from where I started.I had a need to make two white metal bushes and that is why I was curious. This was to fix a jackshaft on a southbend lathe. But for now vesconite is doing the job.

https://bbs.homeshopmachinist.net/fo...w-to-make-this

Thanks for this @plunger. Munch appreciated!

I have joined on that forum and will continue with your thread. Thanks again for your effort to help me. It really means a lot!

[plunger]

I think a simple way to do this on a lathe without having to adapt too much could be as follows. You probably need to do one pass only. So it will cut to depth on one pass. I would set the housing up on a face plate . I would put it in the slowest speed possible.
I would rig a simple spool on the carriage wheel. This could be piece of pipe ,anything that would hold a rope. 9Think mini car rim) Then I would hang a pully or sheath above the lathe and attach a rope or cable to the rim or spool attached to the carriage wheel. Then I would tie some weights to the end of the rope.

All you are trying to do is get the carriage to move forward fast and consistant . Then I would set some stops up and start in the oil hole and end in a groove machined just before the end of the bush. This is not even needed really.
With a internal grooving tool set at depth if you start the lathe and let gravity do its thing it should pull the carriage forward and with a bit of adjustment it could be set up to do a course thread suitable for an oil groove.

Or am I way off thinking clearly here.