# I've bought a DIE without a tap...



## vimes1984 (Jun 2, 2021)

Yes yes yes, I'm an idiot I know 

SO I bought a lovely cheap die on ebay to thread wooden threads:


If i measure in metric
it taps a 38mm diameter at a 6mm pitch

_*OR*_
if I measure it in Imperial it appears to tap 1 1/12 inch diameter @ 4 TPI
The only marking I have on it is "38 x 6" and I purchased it in Denmark so I'm assuming it's a M38x6 die.

Now the twist is that standard bolts tend to skip from M36 to M40 and not at that pitch., again I know I'm an idiot 

So I have 3 questions:


Does anyone have a M38x6 tap they want to sell??
Does anyone know of any local machine shops to ireland that I can contact?
Does anyone here fancy taking this on??
I'm based in ireland and I'll happily pay for this OR do some website work for someone for it


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## T Bredehoft (Jun 2, 2021)

Do you have a lathe?  Buy a piece of 38 mm silver steel, chase threads on it, cut grooves in the length, approximate the taper of a tap. Harden  and draw it, and go to town, you're only cutting wood with it anyway, right?


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## MrWhoopee (Jun 2, 2021)

T Bredehoft said:


> Do you have a lathe?  Buy a piece of 38 mm silver steel, chase threads on it, cut grooves in the length, approximate the taper of a tap. Harden  and draw it, and go to town, you're only cutting wood with it anyway, right?


This^^^^^
Not sure I would even bother to harden it. Might just make it from CRS.


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## T Bredehoft (Jun 2, 2021)

MrWhoopee said:


> Not sure I would even bother to harden it.


As a retired Tool Maker I harden everything. Well, almost everything.


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## mmcmdl (Jun 2, 2021)

T Bredehoft said:


> Well, almost everything.


TMI !


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## vimes1984 (Jun 2, 2021)

I have a lathe but I realllly am not good enough with it to do this....


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## vimes1984 (Jun 2, 2021)

Would someone be up for making one of these for me?


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## ErichKeane (Jun 2, 2021)

If it wasn't metric this is something I could put together, but sadly my lathe doesn't do metric threads :/


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## T Bredehoft (Jun 2, 2021)

mmcmdl said:


> TMI !


Some things, like CRS just won't harden.


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## Papa Charlie (Jun 2, 2021)

Well you couldn't get much closer to Northern Ireland, it would seem. 
Wish I was up and running, I would be happy to help. I am sure that someone will be able to help you.


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## vimes1984 (Jun 2, 2021)

I sure hope someone will help me I'm banging my head against the wall...


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## WobblyHand (Jun 12, 2021)

What sort of thread is it?  Is it 60 degrees, or more like trapezoidal with a flat top?

For folks with imperial lead screw lathes 4 TPI is relatively easy, my mini-lathe can cut it with "0" error.  But I cannot cut 6mm pitch.  Closest I can do is 6.032 mm pitch (0.54% error).  You really need to measure the threads a little better.  Can you cut 10 or more threads with the die and measure the total distance accurately?  (Report the number of threads and the distance from crest to crest.)  You will need a good quality scale or verniers.  If the pitch is metric, all of the threads will line up very well on your (metric) scale.

If you can't do that, then I'd recommend finding a local machinist and ask them to measure the thread pitch accurately for you.  Once you know the thread pitch, you can get a tap made.  As others have mentioned, since you plan to cut wood with it, it does not have to be made out of high speed steel, nor hardened.  Hardening wouldn't hurt, but could improve the tool life.


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## ErichKeane (Jun 12, 2021)

Ba


WobblyHand said:


> What sort of thread is it?  Is it 60 degrees, or more like trapezoidal with a flat top?
> 
> For folks with imperial lead screw lathes 4 TPI is relatively easy, my mini-lathe can cut it with "0" error.  But I cannot cut 6mm pitch.  Closest I can do is 6.032 mm pitch (0.54% error).  You really need to measure the threads a little better.  Can you cut 10 or more threads with the die and measure the total distance accurately?  (Report the number of threads and the distance from crest to crest.)  You will need a good quality scale or verniers.  If the pitch is metric, all of the threads will line up very well on your (metric) scale.
> 
> If you can't do that, then I'd recommend finding a local machinist and ask them to measure the thread pitch accurately for you.  Once you know the thread pitch, you can get a tap made.  As others have mentioned, since you plan to cut wood with it, it does not have to be made out of high speed steel, nor hardened.  Hardening wouldn't hurt, but could improve the tool life.


Based on the model number, I'm guessing it is metric


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## WobblyHand (Jun 12, 2021)

Well, then the OP needs to find someone with a lathe that can cut metric threads with lower error than I can...  

However, the intended use is wood, and we don't know how deep the threaded hole needs to be.  Maybe the 0.54% error is ok.  Probably need to account for moisture absorption for wood threads, so a somewhat sloppy fit is ok.  Since we don't really know the exact application, it's hard to make more detailed recommendations.  Just trying to help...


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## vimes1984 (Jun 12, 2021)

It's definitely M38x6, the usage is to make a wooden bench vise screws. 
It can have quite a bit of slop,.  I have a local machinst looking at it right now hopefully he'll be able to sort me out a tap. 
Thanks for the response!


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## Bi11Hudson (Jun 13, 2021)

Nothing really useful to add, just a similar experience with a couple of 1000 liter totes that I use for catching roof runoff, The tote was (probably) metric. It came from a Honda plant and had import stickers all over it. I started with a PVC pipe coupling from Home Depot. Everything was sized "more or less" and all done in plastic. The coupling was used rather than pipe because of the thicker tubing wall and easy to fit up a smaller pipe. I cut the threads to Imperial size, although I'm sure the male fitting was metric. Using rubber electrical tape, I made a sort of gasket and threaded then together. It doesn't leak in water usage, so is close enough to call it a fit. Some 3(+) inches in diameter, cutting the inside threads was easy enough.

On a philisophical note, I don't really use dies that often. Although I have many wood dies along with the metal working tools. The wood dies work on plastics like PVC quite effectively. When I acquire a "new to me" size tap, I order a matching die even though it seldom, if ever, gets used. Such things should always be kept in pairs. . .  Like this situation, there is no telling what the future holds.

.


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