Author Topic: 1/4 " spark plug copper washers  (Read 666 times)

Offline Laurentic

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Re: 1/4 " spark plug copper washers
« Reply #15 on: May 11, 2022, 10:30:19 PM »
Just thinking on how to part off the 8mm x 1mm wall tube into washers - sounds like a tricky animal to me. 

I wonder if mounting the copper tube on a 6mm dia steel rod first might help???  Not done it, mearly thinking out loud!

Might need to support the rod both ends too???

Chris

Offline Dan Rowe

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Re: 1/4 " spark plug copper washers
« Reply #16 on: May 11, 2022, 10:33:13 PM »
Mike, yes my repairman's reamer is a bit dull also so yes a good point. If I was doing this for my shop I would make a special chuck to hold the OD of the ring and have a screw on cap that held the ring in place then a very sharp boreing bar in the lathe would do the trick.

 :DrinkPint: beer 00:30 here!

Cheers Dan
ShaylocoDan

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Re: 1/4 " spark plug copper washers
« Reply #17 on: May 11, 2022, 10:36:23 PM »
Hello Chris,

Turning and parting copper needs razor sharp tools. Mounting the copper tube over a steel or aluminium rod sounds like a very good idea. Yet another of those 'try it several ways until you find what works' situations.

And there I was, happily draining the swamp until this happened. I only wanted to buy a stock of washers, now  It looks like I will be making them, custom size.

Cheers

Mike
« Last Edit: May 11, 2022, 11:13:53 PM by Vixen »
It is the journey that matters, not the destination

Oh! sod the journey, lets hit the bar and pool instead.

Online Vixen

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Re: 1/4 " spark plug copper washers
« Reply #18 on: May 18, 2022, 10:40:48 PM »
The 8 x 6 thick wall copper tube turned out to be 8 x 5.5, a shade thicker wall than I expected.

I decide to follow Chris's idea of mounting/ supporting the copper tube from the inside with a steel rod. I turned a piece of steel to be a nice running fit inside the 5.5mm ID copper tube. I milled a slot along one side of the steel rod to give somewhere for the parting tool to overshoot into. I ground a special, razor sharp, 20 thou (0.5mm) wide parting tool with plenty of top rake to minimise the amount of copper to be removed

Here you can see the set-up to part of 30 thou (0.75mm) thick spark plug washers from the 8mm thick wall copper tube. I parted off the first few by hand and became confident enough to write a short CNC program to part off eight washers in a batch. The tool position was incremented by 50 thou after each washer with the parting feed rate set very low at 1 inch per minute. The slow feed rate ensured the minimum kerf to be cleaned up.




I now had a pile of undersized (5.5mm hole) copper washers. I made a very simple ring expander by turning a very slow taper on some steel rod. The taper went from 5.4mm to 6.2mm, the size I wanted for my 1/4 x 32 tpi spark plugs. The diameter of the bar above the 6.2mm diameter was relieved and used to catch the stretched (expanded) spark plug washers as they were produced.




This is the result of an hours work. All that's needed now is a careful cleanup and then annealing to soften the copper




When I started I only wanted to buy few spare plug washers. Instead, I ended up making them, enough to last me several lifetimes. Much more satisfying.

Mike
« Last Edit: May 19, 2022, 09:11:56 AM by Vixen »
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Offline Dan Rowe

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Re: 1/4 " spark plug copper washers
« Reply #19 on: May 19, 2022, 12:33:47 AM »
 :cartwheel: :cheers:
ShaylocoDan

Offline Admiral_dk

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Re: 1/4 " spark plug copper washers
« Reply #20 on: May 19, 2022, 12:21:17 PM »
Great result that easily can be copied by others  :ThumbsUp:    :cheers:

Per

Online Vixen

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Re: 1/4 " spark plug copper washers
« Reply #21 on: May 19, 2022, 01:11:34 PM »
Great result that easily can be copied by others  :ThumbsUp:    :cheers:

Per

Thank you, Dan and Per,

Per, that's exactly why I go to the trouble to write up and post my methods.

I now have far more plug washers than I can possibly loose (use) in a lifetime: so if anyone sends a stamped/ self address envelope they can have a few for free.

Mike
« Last Edit: May 19, 2022, 08:01:31 PM by Vixen »
It is the journey that matters, not the destination

Oh! sod the journey, lets hit the bar and pool instead.

Online propforward

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Re: 1/4 " spark plug copper washers
« Reply #22 on: May 19, 2022, 02:19:29 PM »
Nifty solution - I really like the tapered expander idea.
Stuart

Forging ahead regardless.

Online Vixen

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Re: 1/4 " spark plug copper washers
« Reply #23 on: May 19, 2022, 02:30:24 PM »
Hello Stuart,

Reducing the diameter of the tapered expander above the desired diameter, means you don't have to fight the copper ring off the taper.

Mike
It is the journey that matters, not the destination

Oh! sod the journey, lets hit the bar and pool instead.

Offline Roger B

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Re: 1/4 " spark plug copper washers
« Reply #24 on: May 19, 2022, 07:47:35 PM »
That's an excellent solution to your problem  :)  :)  :ThumbsUp:
Best regards

Roger