GottMitUns Posted September 16, 2015 Share Posted September 16, 2015 Can anyone tell if it is possible to cut metric threads with this lathe by the pictures below?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 Link to comment Share on other sites More sharing options...
HWooldridge Posted September 16, 2015 Share Posted September 16, 2015 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... Link to comment Share on other sites More sharing options...
GottMitUns Posted September 16, 2015 Author Share Posted September 16, 2015 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. RussellPSI 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. Link to comment Share on other sites More sharing options...
HWooldridge Posted September 16, 2015 Share Posted September 16, 2015 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 Link to comment Share on other sites More sharing options...
GottMitUns Posted September 16, 2015 Author Share Posted September 16, 2015 forbidden bug bit! Will do if he shows up. Link to comment Share on other sites More sharing options...
Alan Evans Posted September 16, 2015 Share Posted September 16, 2015 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 Link to comment Share on other sites More sharing options...
ianinsa Posted September 16, 2015 Share Posted September 16, 2015 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' Link to comment Share on other sites More sharing options...
GottMitUns Posted September 16, 2015 Author Share Posted September 16, 2015 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 Link to comment Share on other sites More sharing options...
ianinsa Posted September 16, 2015 Share Posted September 16, 2015 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 Link to comment Share on other sites More sharing options...
HWooldridge Posted September 16, 2015 Share Posted September 16, 2015 Russell,I assume you did already check whether one of the English threads is not a match for what you are attempting. A few pitches are quite close.Hollis Link to comment Share on other sites More sharing options...
GottMitUns Posted September 16, 2015 Author Share Posted September 16, 2015 Of course I haven't Hollis, that would be to simple if it works! I am going to go pull some prints right now and look at it.Thanks Link to comment Share on other sites More sharing options...
GottMitUns Posted September 16, 2015 Author Share Posted September 16, 2015 1.5 mm= 16.9333 TPI = .0590 per rev16 TPI = .0625 per rev18 TPI =.0555 per revby 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. ThanksRussell Link to comment Share on other sites More sharing options...
HWooldridge Posted September 16, 2015 Share Posted September 16, 2015 Well, it was worth doing the math...now you know for certain. Link to comment Share on other sites More sharing options...
Alan Evans Posted September 17, 2015 Share Posted September 17, 2015 (edited) 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 September 17, 2015 by Alan Evans Link to comment Share on other sites More sharing options...
ianinsa Posted September 17, 2015 Share Posted September 17, 2015 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. ThanksRussell Wow, to be out by 0.00008mm no self respecting blacksmith could EVER ACSEPT ANYTHING SO FAR OFF FROM SPEC. Link to comment Share on other sites More sharing options...
swedefiddle Posted September 17, 2015 Share Posted September 17, 2015 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 Link to comment Share on other sites More sharing options...
GottMitUns Posted September 17, 2015 Author Share Posted September 17, 2015 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. Russell Link to comment Share on other sites More sharing options...
yesteryearforge Posted September 17, 2015 Share Posted September 17, 2015 Maybe try ( practical machinist ) forumSomeone there can tell you for sure Link to comment Share on other sites More sharing options...
GottMitUns Posted September 17, 2015 Author Share Posted September 17, 2015 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 Link to comment Share on other sites More sharing options...
HWooldridge Posted September 17, 2015 Share Posted September 17, 2015 Better be sitting down when you read that quote on the gears... Link to comment Share on other sites More sharing options...
GottMitUns Posted September 18, 2015 Author Share Posted September 18, 2015 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! 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 Link to comment Share on other sites More sharing options...
ThomasPowers Posted September 18, 2015 Share Posted September 18, 2015 or make friends with a fellow who will lend them to you... Link to comment Share on other sites More sharing options...
GottMitUns Posted September 18, 2015 Author Share Posted September 18, 2015 Its always nice to make friends with the guy who has the most toys Link to comment Share on other sites More sharing options...
rjs Posted October 3, 2015 Share Posted October 3, 2015 If you can replace the 120 tooth gear with a 127 tooth gear you can cut accurate metric threads. Regards,,Bob Link to comment Share on other sites More sharing options...
Frosty Posted October 4, 2015 Share Posted October 4, 2015 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 Link to comment Share on other sites More sharing options...
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