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Author	Topic: Lathe spindles
rjibosh unregistered	posted 04-22-2003 10:58 PM Greetings, This is my first post. I am considering replacing the spindle on my vertually one of a kind 8X20 Tool Mex TSB20 lathe. The main reason for doing this is the spindle mount which is a very irregular geometry. I would appreciate any insight into: material selection,heat treating,best or most useful type of spindle mount configuration. Any other advise etc. Thanks Rick IP: Logged
rjibosh unregistered	posted 04-23-2003 10:43 PM Will. What do you think about using 4140. Having it gun drilled thru. Turning all the steps and threads. Then leaving the bearing taper, nose taper and faces about .010 oversized. Normalizing at about 1700 F and quenched at about 1600 F. Then grind down the bearing seats and tapers. Any one know where I might find specs on 1 1/2-8 spindle mount? IP: Logged
Mike Burdick Member Posts: 49 From: Utah Registered: Jan 2003	posted 04-24-2003 12:32 PM Rick, I don't think there are any so called "specs" regarding a 1 1/2-8 spindle mount - each lathe manufacturer seemed to have thier own - so make it to fit the chuck you want to use. Also, there have been many discussions on these boards regarding the need for the 'register' portion of this mount but I think the general consensus was that it was not needed. Maybe you could search the machinist forums for these discussions so you can decide for yourself. What about making the spindle from 4140 HT? It has a RC of around 30. This way you could avoid all the hassles and expense of having it treated. Anyway, just a thought. If you choose to make a different type of nose connection here are some dimensions to see if they will work on your lathe. http://shopswarf.orcon.net.nz/chuckmt.html [This message has been edited by Mike Burdick (edited 04-25-2003).] IP: Logged
Forrest Addy Moderator Posts: 726 From: Bremerton WA USA Registered: Dec 2000	posted 04-24-2003 12:43 PM I wouldn't have a threaded lathe spindle on a bet. I strongly suggest you build your new spindle with an A1-3 spindle nose configuration. This has a short taper/shoulder registration where the chuck attaches with bolts. The A1-3 doesn't appear in the link but it's dimensionlly identical with the D1-3 but without the cam-lock feature. http://www.rohm-products.com/lath2m.htm It's much easier to make than a cam lock spindle nose and you can reverse your lathe without worrying about the chuck unscrewing. IP: Logged
Appie Chappie Member Posts: 58 From: Vredenburg 7380 South Africa Registered: Feb 2003	posted 04-24-2003 01:00 PM Greetings all, We have a lathe (new) that we call chatterbox. We decided we would replace the main spindle with a super duper heat treated steel. Roughed,stress relieved,semi finished and stress relieved, hardened and finished with CBN. Finished the nose in situe and even stole off a few mm to keep the chuck closer to the main bearing. Now that was the answer we thought. We used a university student, who was doing some practical as a training and research excersize. The bloody thing still chattered. His research ended up showing that the spindle flexed in the middle and that no matter what we use, the same thing would happen, irrespective of the steel and hardness. That was hard to swallow, so we got the research checked and the result was proved to be correct. I now know how to fix it, but what an interesting excersize. The one most impotant aspect was that the spindle bearing seats and nose have to heat treated. We used 835m30 ( EN 30B ) 1540 MPA Real good stuff. The message was that no matter what we used we would end up with the same flex, heat treated, tempered down or as is. Had me disbelieving until a prof showed the proof, me still saying, cook that steel and you try and bend that....had to eat my words. Have fun Andy IP: Logged
J Tiers Member Posts: 798 From: St Louis Registered: Jun 2001	posted 04-24-2003 01:32 PM I would avoid the threaded spindle just because. I do have one, and it has only unscrewed once, when I deserved it (threading in reverse and deep cut). I will say that threaded spindle compatible stuff is cheap and available, easy to make yourself, and generally not a death warrant as some seem to think. But, with the choice, and an unlimited budget, go for a modern type. It triples the costs, but is nicer all around. IP: Logged
John Stevenson Member Posts: 197 From: Nottingham, England Registered: Apr 2001	posted 04-24-2003 02:00 PM I'll go with Forrest on this one and use an A type Din3 mounting. As Forrest says they are dimentionally the same as a D-3 but just have three holes it them for the studs, basically it's a arge flange with a short taper and 3 holes. Possibly even easier to do than a threaded spindle. Up shot of this type is you can reverse the machine with no problem and it will allow to to get the most thru the spindle. A better link on spindle sizes is here:- http://www.workholding.com/prattadaptor.htm Appie Chappie has put some good remarks forward and depending on the layout it may pay to replace the pullies with a single large cast iron assembly using poly V belts. This when clamped onto the spindle will give a greated damping than small alloy vee pullies. John S. IP: Logged
RJIBOSH unregistered	posted 04-25-2003 08:36 PM Thank you all for your generous and helpful replies concerning upgrading my current lathe spindle. It looks like it might be easier to make a few extra back plates to fit my present spindle than replace it. The existing spindle is similar to an L series but smaller and the taper is slightly different. I guess its design advantages outweigh its dimensional shortcommings. Thanks again, Rick IP: Logged
dennh Member Posts: 135 From: northeast Registered: Sep 2002	posted 04-25-2003 10:19 PM RJIBOSH: Do you by chance have one of the funky spindles like the Emco Compact 8 and some other larger and smaller Emco machines (Maximat 7, Emcomat 8.4, 8.6)? They have a short taper and a flange with three holes for studs which are attached to the chucks, faceplates, etc. Sorry but I'm not near it now. The taper diameter is around 42mm (at the flange end) and the overall flange is around 72mm. If you do, you may want to check with Blue Ridge Machinery. They still have a number of items which will fit it. Den IP: Logged
rjibosh unregistered	posted 04-26-2003 04:37 AM Den, I don,t think this spindle has a twin outside of Poland where the lathe was made. The taper is 8 degrees. The small dia is 34.078mm and the large is 50. Taper is 20mm long. The lathe was marketed by ToolMex and made by Ponar Remo in 1991. ToolMex USA says Ponar Remo's main output was specialty spindles but cannot supply any spares or plates. I'd like to start a Ponar Remo Lathe club but I doubt anyone else could join it. Thanks for the input though. Rick IP: Logged

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