Buying a new lathe

[GaryK]

Do you have a link for those knobs?

Thanks
Dan

I got them at McMaster-Carr. Under Plastic Threaded Ball Knobs

I got 2 each of:
Red Polypropylene Ball Knob, 5/16"-18 Thread, 1-1/4" Diameter
Red Polypropylene Ball Knob, 5/16"-18 Thread, 1-1/2" Diameter

Also 1 of:
Metric Red Phenolic Ball Knob, M10 X 1.5 Thread, 34.9 mm Diameter

Which fits the Chinese quick change tool post.

 

[darkzero]

In the past I got them from Enco, made by Gibraltar. They have the ones with the threaded inserts too nut not in metric. I always bought the "universal" ones that cover a range of thread, you just thread them on. I never had an issue with them stripping.

 

[GaryK]

In the past I got them from Enco, made by Gibraltar. They have the ones with the threaded inserts too nut not in metric. I always bought the "universal" ones that cover a range of thread, you just thread them on. I never had an issue with them stripping.

I hadn't seem those from Enco. Cool about being able to use different thread sizes. The McMaster ones have a brass threaded insert which I think I would be more inclined to trust more over time. The KDK QCTP was 5/16-24 so I had re-tap the insert but it worked just fine. McMaster does have a larger selection of sizes.

 

[jpfabricator]

Nice! Collets are a good thing -do a lot of work with them since many jobs I get are on existing shafts that are fairly true but have no centering holes and/or I can't divot the sides to mount with a dog. Fortunately most are between 1" and 1-1/8" too... I get the odd one that's over 1-1/8 and need to fight with jawed chucks to hold it straight. Usually, I'm rebuilding the threads on outboard motor prop shafts after doing a build-up and re-thread or conversion to a different attachment method.

BTW: The PM bench is OK but, I think that lathe would benefit from being bolted to 500lbs of cast iron. That's my guess. When I have to make a long shaft from scratch, I get some noise marks going past the 18" mark and every bone in my body says it's from the light side moving a tiny bit. -Not a real problem worth crying over. Been thinking of beefing-up that bench but it's not as easy as I wish it were. Still thinking of the best way to do it but haven't thought long/hard enough. How bout you, any ideas?

Weld re-wire into the bases and pour them full of concrete!!

 

[GaryK]

Sand bags will work also. Lead if you are a reloader that casts your own bullets.

 

[Ray C]

No, no, no... MORE TOOLS for ballast!

Sand bags will work also. Lead if you are a reloader that casts your own bullets.

 

[GaryK]

Just in case anybody is curious about the actual size of the spindle bore is, it's 1.470". It's bigger than that up toward the chuck, but farther back
it is a smaller diameter all the way to the threaded end.

At least that is what my PM1236 measures.

Gary

 

[darkzero]

Just in case anybody is curious about the actual size of the spindle bore is, it's 1.470". It's bigger than that up toward the chuck, but farther back
it is a smaller diameter all the way to the threaded end.

At least that is what my PM1236 measures.

Gary

Gary, that's interesting & you got me wondering as I've never actually measured mine. Mine is also bigger towards the chuck size as a D size Maglite won't fit all the way through. But I was working with 1.5" bar today & it did fit past the larger section. I'll measure mine later when I go back to finish what I was working on.

By any chance do you have a MT5 center on hand? If yes could you check if it will seat in the taper properly? On my spindle a full size MT5 center won't seat the taper properly as the back end of it will hit the smaller bore of the spindle just before it can seat the taper. A MT5 center is too big to use as I need anyway but I was just curious as another peerson I know with the same lathe did not have this problem.

 

[GaryK]

Gary, that's interesting & you got me wondering as I've never actually measured mine. Mine is also bigger towards the chuck size as a D size Maglite won't fit all the way through. But I was working with 1.5" bar today & it did fit past the larger section. I'll measure mine later when I go back to finish what I was working on.

By any chance do you have a MT5 center on hand? If yes could you check if it will seat in the taper properly? On my spindle a full size MT5 center won't seat the taper properly as the back end of it will hit the smaller bore of the spindle just before it can seat the taper. A MT5 center is too big to use as I need anyway but I was just curious as another peerson I know with the same lathe did not have this problem.

What I did, since I have no tool to measure so deep into a hole is to attach a disk to the end of a rod, and then kept turning it down and test fitting it.



I cut .020" at a time so at 1.490" it was just too big and at 1.470" it fit a little loose.

My spindle bore narrows down at 5.175" from the front face of the spindle (not the tapered nose). So to answer you question, yes I do have a #5 MT center and it did fit.
I actually tried it today. but it protruded too far out to allow me to use my dogs. The legs weren't long enough to reach the face plate. So good news, bad news for me.
I was making a test bar to get my tail stock centered. It was only about .0015" off so the factory did a pretty good job.

I guess the factory was using a shorter drill bit the day they drilled your bore. :-(

You could just shorten your center or get a big drill bit and open you bore deeper or all the way through.

I ended up doing that with the lever collet closer I have. It only had a 25mm bore through it so I couldn't put a 1" bar in it. I drilled it through at 1.0312".

 

[darkzero]

Thanks Gary. For the same reason you mentioned, I won't be using the MT5 center. With my dog plate the MT5 center sticks out way to far for my liking. I would imagine using the faceplate as a dog plate it would stick out even more. I ordered a bearing steel import center from Enco that was on sale & applied a 15% discount to it. What I received was a Bison center which was a nice surprise, it would be a shame to cut this sucker down. I'll just store it away for now. But anyway, I won't worry about it & will stick with using the sleeve & a MT3 center (also got a Bison to replace the one that came with the lathe).

Here it is with the MT5.

Here it is with the MT3 which is perfect for my dogs.

Looks like my spindle bore is slightly bigger. I'm able to fit a 1.5" bar all the way through with no snags at all.

Here's what I measured at the smallest point I could reach.

I can't imagine them using a drill bit to bore the spindle but who knows. I wonder if anyone has actually tried to bore the spindle on these 12x36 lathes. Looking through my spindle it's not bored perfectly through. Aside from the larger bore towards the front, my spindle is slighty bigger on the threaded end just before the threads about 3" deep. I measured the bore about 6" deep from the threaded end.

In regards to the TS, the stock set screws are junk. They are so loose. I've been meaning to order replacements on the next Mcmaster ordered but recently a friend did the same & sent me pair of replacements since they come in a pack of ten. I never stripped mine yet but man do the replacements feel so much more assuring.