New Lathe

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DrAl

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Considering getting a new lathe to replace the LMS 7x14. Does anyone have experience with Bolton Tool and Precision Mathews. Both have some machines that look reasonable. The BT1324 has my eye, and the PM1030V looks to be OK. Neither has a separate feed rod, and I wonder how important you folks think that separate rod is.

The next step up is the 12 x24 that Charter Oak carries, the Bolton CQ9332A, or the G4003 from Papa Grizzly.
 
I've heard lots of good things about the PM machines. I have not heard anything about bolton, but that doesn't mean it's no good.
 
Wreck" data-source="post: 382430" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">
WreckWreck said:
Why the question about a separate feed rod, please explain this.
Click to expand...
I think he's asking about a separate shaft for longitudinal feed rather than using the lead screw for both power feed and threading. Lathes frequently have them to reduce wear on the lead screw, which is then only used for threading.


Steve Shannon, P.E.
 
I understand that, yet is it a concern with a hobby machine?

I had a nice 1960's 14 X 48 Clausing with one screw, the lead screw had a keyway in it that drove the apron gearing, the half nuts ignored the key seat when in use. Clausing made thousands of these lathes. I bought it used from a production shop in 1990 and used it daily until I sold it in 2013 without issue or significant wear. When first bought the lead screw threads at the chuck were fairly worn from decades of use, I flipped it over and put the worn end near the tail stock.
 
You asked for an explanation. I tried to provide one. I'm sorry I did.


Steve Shannon
 
DrAl said:
The BT1324 has my eye, and the PM1030V looks to be OK. Neither has a separate feed rod, and I wonder how important you folks think that separate rod is.
Click to expand...
Many 7" lathes (possibly including earlier LMS 7 inchers) with a single rod/leadscrew were also missing a rack on the underside of the ways (and a second lever, or lever position on the carriage). The only way to set up a power feed was to set up the gearing for a super-fine thread, and use the leadscrew. This was kinda inconvenient.

I looked at the PM1030V, and it, like many lathes in the 9-10 inch size (plus the newer LMS minis) does indeed have two levers on the carriage. The power feed lever engages a worm gear drive (driven by a key slot in the leadscrew) that's quite a bit slower than what you'd get with the half nuts (though not as precise, so you shouldn't try to cut threads that way). So without making any gear changes inside the headstock, you can use one setup for both feeding and threading.

The "advantage" of making a lathe with a single rod is cost. The disadvantage (for you) is that a threaded rod with a key slot is a bit harder to clean than one without. IMHO, it's not a big issue either way.
 
Wreck™Wreck said:
I understand that, yet is it a concern with a hobby machine?

I had a nice 1960's 14 X 48 Clausing with one screw, the lead screw had a keyway in it that drove the apron gearing, the half nuts ignored the key seat when in use. Clausing made thousands of these lathes. I bought it used from a production shop in 1990 and used it daily until I sold it in 2013 without issue or significant wear. When first bought the lead screw threads at the chuck were fairly worn from decades of use, I flipped it over and put the worn end near the tail stock.
Click to expand...
The good thing about the Clausing (and many others) design is the lead screw has a key way on it that drives a gear trapped in the apron. When longitudinal or cross feeding, the lead screw is rotating which in turn turns the drive gear in the apron. The lead screw wear (if any) will be on the key way as the trapped gear slides side to side during longitudinal feeding (no movement when cross feeding). I'd think they'd have used a softer material than the lead screw so the key would wear during feeding, not the lead screw.

If the lathe you're looking at has a keyed lead screw, it's a copy of the Clausing type design (don't know if they originated it or not) and in my experience would not be a wear problem on your lead screw. I have a 1963ish Clausing 5418 that my dad purchased for a high school shop. It was used fairly heavily for about 12 years until shop classes gave way to computer programming classes (at least at my dad's high school). I measured the tip of the lead screw at different places along the screw and can't find any wear.

If your lathe doesn't have the keyed feature on the lead screw, it's like an Atlas 12" lathe (maybe others) that uses the half-nuts for longitudinal feeding. In that case, you may want to post a question in the Atlas forum asking about half-nut wear. They sold a lot of Atlas lathes with that system, don't see a boat load of half nuts for sale on eBay so it must work for the hobby machinist as you mentioned.

You'd like to think a reputable modern seller of machine tools would have a decent design for wear on the half-nuts if that's the system used. However, do a thread search on the forum for someone with a combo lathe/mill who was trashing half-nuts left and right. I think he ended up having his aprons gibs too tight causing a lot of wear on the half-nuts but don't quote me on that.

Bruce
 
Steve Shannon said:
You asked for an explanation. I tried to provide one. I'm sorry I did.


Steve Shannon
Click to expand...
No need for sorrow, I merely pointed out that manufacturers have produced reliable long lasting single shaft lathes for decades and wondered why it would be an issue at all. This question has not been answered.
 
The original poster, lacking your experience, was asking for help in determining whether it would be an issue. When you asked for an explanation it wasn't clear what you needed explained.
I don't have sufficient experience with comparing single shaft lathes to double shaft lathes or I would have tried to help him.
My sorrow was in wasting time taking your request for an explanation at face value.


Steve Shannon
 
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