Cylinder head mandrel?

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7/10/2018 10:25 AM

Anyone know where I can buy a 14mm cylinder head mandrel to cut 2 stroke heads? I've looked at Goodson's site and google with no luck. I can probably make one but I figured the tooling I'd have to buy to cut the threads would be about the same as the mandrel- and quicker. Thanks.

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7/10/2018 11:16 AM

Not sure where you can just buy one, but I've made one out of steel with single pointed threads on our manual Hardinge and also one out of aluminum with threads cut using a basic die. Both worked fine. If you've got a lathe and a die, you're all set.

Here's a photo of the aluminum one I made:

Photo

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Billy Wight
Luxon MX
@LuxonMX
https://luxonmx.com
Motocross Components Engineered for Performance

7/10/2018 11:22 AM

I also made one on a lathe a while back. Works great. That might be your best option.

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7/10/2018 12:30 PM

You guys are hi-tech! I just made one out of an old spark plug I turned on my lathe, been working like a champ for 12-13yrs...

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7/10/2018 1:24 PM

Drilled and tapped a piece of aluminum stock, used another piece of aluminum stock I turned down on the lathe and cut threads onto with a die threaded into the head and into the aluminum stock to mount in the lathe .

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7/12/2018 10:52 AM

Thanks for the input fellas. I went the slipdog route and just turned an old plug down and went for it. Took a bit of finagling to get it chucked up true in the lathe, but I eventually got it under .001 run-out. Just took my time cutting and it turned out great. Checked it last night and squish clearance is right at .035, so I should be good to go!(feel free to give your opinion on that spec for a 125.) This was literally the last piece needed to get this engine done so I didn't want to put the time in to make a quality one(I've never cut threads on my lathe so didn't want to tackle acquiring that skill set before getting this done), but it is now on my projects list.

Photo

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7/12/2018 3:22 PM

Did you cut that on a lathe, or the shop floor?

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7/12/2018 5:05 PM

FahQ wrote:

Did you cut that on a lathe, or the shop floor?

I only cut the dome on the lathe- it's been hit with scotchbrite in this pic in preparation for thermal barrier coating. The head itself I cut on the concrete, gonna shred cheese on it later for shits and giggles. Don't worry, I'll finish it on the surface plate(after the coating) before installation.

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7/12/2018 7:34 PM

.035" is fine on a 125, IMO.

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