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cutting metric threads

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Can anyone tell if it is possible to cut metric threads with this lathe by the pictures below?

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my Shop lathe lists metric threads on its "gear selection" but this one does not.

 

I know that because it has a "American" leadscrew  that if I do find the right gear I will have to leave the half nut engaged and stop the machine at the end of the threads, pull out, and then reverse the machine back to my starting point.

 

Thank you,

 

Russell Doerr

 

IMG_2050[1].JPG

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It's an Imperial (English/American) gear set.  Only way to cut metric is if one of the TPI settings happens to coincide with a metric standard.

Or you'll have to change out one or more gears...

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Thanks HW.  I did a little more research last night and found a small blurd on it on a English machinist site with a picture of a almost identical lathe, only it had a second gear chart above the one on my lathe.  I  received extra gears when I bought the lathe but no manual, I think one of the gears is a 127 tooth that is mixed in somewhere to get metric pitches, but I'm not sure where. Fun fun fun.
 

 

Russell

PS

I see you are in central Texas, The Goliad Forge is meeting at my shop in Victoria Tx this Saturday from 8:00 am if your interested and the drive is not to far.

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Hi Russell,

I'm in New Braunfels and occasionally try to make the Balcones Forge meetings but it's rare that I can get away for a Saturday - just too much going on right now.  Thanks very much for the invite anyhow.  Say hello to Kort Angerstein for me if he ever shows up there.

Hollis

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I seem to remember seeing a lathe with an alternative lead screw hanging up beside it which could be swapped in for metric/imperial. It was an old Colchester or Harrison I think.

If you are making bespoke threads can you make both pieces, male and female? It wouldn't matter what thread form then. I only say that because both of my lathes would only cut imperial threads, and I deliberately avoid it by drilling and tapping and using all-thread/studding between two home made acorn/pike nuts rather than cutting any male threads.

Alan

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Not being nearly as smart as you lot I cheat! I mount a tap in a chuck the tailstock or I use a die(for those confused I'm not referring to a hammer:)) sort of jerry-fixed using the lathe as a 'powerdrive' one day i'll get someone to teach me to use the lathe 'proper like':D

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Ianinsa,

   threading is only scary the first few hundred times you do it,, you'll have it down in no time!!  My old machinist who retired on me could carry on a conversation, joking and cutting up while cutting a 8 TPI tapered pipe threads. I get highly PO'ed at the ticking of my watch while I'm doing a simple 16 TPI straight thread at half the RPMs!

 

I wish I could get away with it but I think not on this project. this is a rifle re-barreling project on a Howa/Weatherby vanguard action.

Thanks Guys

 

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In the days when my business was really busy I had employed guys that used the lathe, shaper and milling machines as intended and I didn't take enough time out to learn enough.

Well such is life, as for being scary, nah as long as it doesn't break me or someone else! Tips, tooling and bits of steel can usually be easily replaced! I on the other hand don't heal so easy no more 

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1.5 mm= 16.9333 TPI = .0590 per rev

16 TPI = .0625 per rev

18 TPI =.0555 per rev

by the time I get .600 of thread engagement I would be off by about 1/2 a thread (.030 +/_ ) either way I go.

 

I did find the chart and formula for using change gears that should get me to a error of .00008MM if I have the correct gears at home.  the hunt continues.

 

Thanks

Russell

 

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I just looked at my old Ward 7 lathe plate and that has two charts, each one for a different lead screw if I read it aright.

You photo has the legend at the bottom 4tpi leadscrew so I think that is the key.

Any handbooks available to download for your lathe?

Alan

Edited by Alan Evans

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I did find the chart and formula for using change gears that should get me to a error of .00008MM if I have the correct gears at home.  the hunt continues.

 

Thanks

Russell

 

Wow, to be out by 0.00008mm no self respecting blacksmith could EVER ACSEPT ANYTHING SO FAR OFF FROM SPEC. :D  

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I got in trouble with a very close friend of mine. He said "You darn machinists, you are allowed to be within one ten thousanth out. Us Carpenters have to be RIGHT ON"!!!!

Maybe you had to be there to appreciate the Humour. Or maybe it was the wobbly pops (LOL)

Neil

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I found a stack of gears but no manual so I will be going back online to see If I can find a reprint. 

The chart I printed off the net is different enough that I want more backup before I try it.

I think I have everything except the knowledge to know where to stick what gear:D.

 

Russell

 

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The good news is the Tech support guy at Clausing is top notch, and I now have  a PDF copy of the 1979 manual for my lathe!

The bad news is it looks like the extra gears I have are for a different clausing lathe in my shop.

Now I have them quoting their optional metric gear set, hoping they still have some in stock.

Fingers still crossed!!

 

Russell

Yesteryear

 

I have been lurking the practical machinist sight trying to learn enough to ask a semi intelligent question,,and understand the answer!!

 

Russell

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YEP!!! just over 2/3 of what I paid for the lathe 6 years ago, for 5 small gears and a gear chart! 

 They had the quote ready to go because someone bought the last set they had on the shelf, at that price, a couple of months ago! They must have had a paying job to cut metric threads:D

 

 Now that I know what new cost I will be investing a lot more time in a work around and searching for used! Its good information to have.

 

Russell

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If you can replace the 120 tooth gear with a 127 tooth gear you can cut accurate metric threads.  

Regards,,

Bob

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Make friends with a shop teacher or someone who owns a lathe. Believe it or not folk like that are pretty easy to meet if you hang out with the counter culture at the local coffee shop. The guys know everybody in town for at least a generation back, who does what, who to or not to trust, Who has what where,  All the good stories some generations old. All the good stuff the tourist information folk are clueless about.

Please feel free to stop by, we can move my lathe out of the connex, set it up in the space we clear in the shop and you can go to town. 

Frosty The Lucky

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