How would you make these?

Hi I would make steel tool with all the tapers on but slightly too deep, cut a ring of tube and get it hot and enlarge it to fit into the tool, next get it hot again and force it into the tool hot. Glue the ring to a flat plate with superglue and reduce thickness to size with a surface grinder or by making a steel ring to go round the outside and hardening it then use it as a guide when linishing the component down. If you cant do it get back to me. Peter

Reply to
petercolman45
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Find a Dowty seal that fits and call it good?

Mark Rand RTFM

Reply to
Mark Rand

The hardest copper you can get will still machine a little like chewing gum. Soft copper, a bit more like warm chewing gum. Ok, so maybe not quite as bad as that, but there are days when things go well, and others....

To anneal copper it must be brought up to a fairly high temperature, and cooled. There is not much to be gained by quenching, except that it shortens the time that the hot copper is exposed to the oxygen in the air. Less scale on the part! I have used a pile of twigs, burning, and a nearby mud puddle, to anneal the head gasket on my Norton, on at least one occasion. A bit of a rubdown with a scotchbrite pad, and a rinse, and all will be pretty again!

Copper is hardened by working it, and heat only makes it softer. Sometimes, with an anneal, a copper gasket can be re-used, sometimes not.

For forming it in a die (the die will form the profile, yes, rather than just cuttin out the rings?) anneal the copper to a dead soft state.

Using a hydraulic press?

Upside of making the dies is, that if it works, it'll be dead easy to reproduce the parts once word gets about that you can! Sometimes projects like this can take on their own life!

Oh! The wax chuck. Think of a faceplate, with some shellac or enravers wax on it to set the part into. Slow, but a means to hold something that cannot otherwise be held very well. An idea stolen from the clockmakers and watchmakers! Used it! Works!

Cheers Trevor Jones (just keep adding lumps until I say stop!) :-)

Reply to
Trevor Jones

Oh! I see you mean the double sided sticky tape chuck. ;-)

Reply to
Richard Edwards

I've annealed quite a few head gaskets etc over the years. My concern when you suggested using the hardest copper available was that it might be an alloy which wouldn't soften as fully as the 'real thing'.

The current plan is to turn up a plain disk, form the profile with the die, then skim off the OD.

Yes, I've got a little laboratory press with only 4" daylight which has been sitting in a corner waiting for a job like this. It's nearly been chucked more than once.

Probably not much prospect of that in this case, I think if successful I'll be supplying the world market as it is (I believe that includes China ), though it'll be worth keeping the dies in case of repeats.

I have to brave the outdoors for some 'real' work today, but will get back to it soon.

Thanks Tim

Reply to
Tim Leech

Or a super glue chuck. Variations on a theme.

Cheers Trevor Jones

Reply to
Trevor Jones

Nope! Copper. Not alloyed copper. The hardest you can get is going to be a wrought product of some sort, either a drawn tube, or a rolled sheet, to harden it.

The OD is the dimension that has the tight specs on it. Makes sense. I would consider trying to work out the dimensions required for the blank, to press it to a finished article in one shot.

Know anyone in metals? I shouldn't wonder that there was an aluminum alloy suitable for the duty these will do.

Cheers Trevor Jones

Reply to
Trevor Jones

I've got back to this in the last couple of days & have worked out a technique which should give consistent results (I'll try to post some details when the job is done), but I'm having trouble getting consistent parting-off cuts. I'm using a thin HSS blade, and found that 'pecking' works better than a steady feed. Trouble is, sometimes - often enough to be a real pain

- all hell seems to break loose when halfway through, and suddenly the parting cut becomes a wide vee with burred edges. I can only imagine that it is a bunching of swarf which causes this, although usually it comes off in a nice curl, but it happens so quickly that it's hard to tell. Any suggestions from those who have survived the copper turning initiation rites?

Cheers Tim

Reply to
Tim Leech

Tim what are you using for coolant?

I find a sulphur based cutting oil works well. Don't use solubles in my Hardinges.

Wayne......

Reply to
Wayne Weedon

Wayne

I was doing this part of the job dry, partly as it's a fairly 'low power' operation, partly because I haven't got the coolant up & running on that lathe yet. I have a handy can of neat cutting oil I could try, or swap to another lathe with soluble coolant.

Tim

Reply to
Tim Leech

or give up and let someone else take the grief as suggested in the first place?

Reply to
Dave Baker

Nah, I've done the *hard* work now

Tim

Reply to
Tim Leech

It's probably snatching when the temp gets high enough. Doesn't take much with copper.

High Sulphur Oil will also reduce any buildup on the tool edge. But will likely stain the material. Not a problem probably especially if you are annealing later on.

Wayne.....

Reply to
Wayne Weedon

I've found that a bit of neatcutting oil dribbled from the can, coupled with a bit of extra lapping on the tool, has worked wonders. Much less burring at the end of a cut, too. ;-)

Thanks Tim

Reply to
Tim Leech

Well there was quite a bit of that, but I got there in the end.

Pics from

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The die was made from 3"-ish MS bar, with a removeable spacer, closely fitting in a recess in the main die, hardened & ground to the finish washer thickness, and an ID a few thou under the final size to allow for the washer springing out when removed. There was clearance on the inside to allow surplus material somewhere to go, though too much surplus would foil the plot so turning the blankhad to be fairly closely controlled. The spacer was easily chucked in the lathe to permit cleaning up the ID. Theory was that the OD would not need further finishing, but in practice during the course of pressing out 30 or so of these washers the whole assembly including the outer die expanded by a few thou, so the majority needed finishing on the OD but that was no great hardship.

I had some smaller (7/8" OD) versions of the same washer to make, decided to do these entirely by turning from tube as I got hold of some with the right OD & ID. I would probably use the die method if doing it again though there wasn't an awful lot to choose between the two in terms of overall time and 'GFA' once I'd decided on the methods. One benefit of using the die method for the larger washers was that I could use some 1" nominal bore tube which I had to hand, the OD on this was a few thou undersize after cleaning up so turning them wasn't an option with this material. Another benefit of pressing them is that the copper is much easier to turn cleanly afterwards as it's harder .

Picture 9 shows the tumbler I used to finish them off, a fancy tea tin which a kind soul gave us for Christmas - the tea was excellent BTW - with some silver sand inside & the lid taped up, run in the lathe for half an hour at maybe 70 rpm. Some coarser media might have been a bit quicker, but that was just what I could lay my hands on at the time. Pic 10 includes some special-size plain washers which were part of the same job.

Tim

Reply to
Tim Leech

and others.

My You have been busy :-). All I've done since Christmas is make one and a half pinions. Albeit the last ones I need to make for now.

Mark Rand RTFM

Reply to
Mark Rand

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