New PM-1236T Lathe has arrived

Today I continued cleaning and inspecting the new lathe. I also got the stand partially erected. It looks like it may be tall enough for me without having to make a base for it.
20220810_144126.jpg


It looks like I will have to cut away the pallet to get the crane up to it.
20220810_144146.jpg
 

Attachments

  • 20220810_144126.jpg
    20220810_144126.jpg
    420.4 KB · Views: 133
I measured the spindle taper runout to be about 0.0001". Axial runout is about the same. That's one tenth of a thou.

And one more spindle runout test after mounting lathe on the stand. About 0.0001". I also checked the axial runout. None measurable.

I also measured the 3 jaw chuck with a 1/2" drill blank inserted. This is an economy chuck, so I was not expecting much of it. It is nearly 0.004". I know now this test means little or nothing.

So I will be shopping for a good Asian made replacement. Shars has some options.
 
Last edited:
 
Have you seen any positive comments on this one? Apparently it can be dialed in to run true.
6″ Adjustable Ultra Precision 3 Jaw Chuck, D1-4 Mount
 
Today I continued cleaning and inspecting the new lathe. I also got the stand partially erected. It looks like it may be tall enough for me without having to make a base for it.
View attachment 416810

It looks like I will have to cut away the pallet to get the crane up to it.
View attachment 416811
In the past when faced with wide pallet/narrow hoist legs situation I've managed to lever the pallet up and onto the legs of the hoist. From there I've hoisted off the pallet and carried on.
I've also taken the outriggers off and moved them outboard using some appropriate sized stock as long pins sleeved with black iron pipe in the space where the outrigger normally goes.
(I hope that makes sense...)
 
Have you seen any positive comments on this one? Apparently it can be dialed in to run true.
6″ Adjustable Ultra Precision 3 Jaw Chuck, D1-4 Mount
I'd post a new topic specifically asking about that chuck. That will get more responses that you'll get in this thread. What I can say is that I would avoid a chuck made on mainland China, and focus exclusively on one from Taiwan, or from Europe (Bison, TMX, PBA) if you can afford them. Make sure you get one with 2-piece jaws. Having Set-tru (Adjust-true) facility is a real plus.

When I bought my PM1340GT in 2015, Matt (at PM) was able to supply a 6", 3-jaw, 2-piece, Set-Tru type chuck made in Taiwan by Chandox for me. It's a terrific chuck and I love it. Here's a photo of the chucks PM supplied - the 4J is nothing special, but does the job (I wish it had 2-piece jaws).

MR - 1 (2).jpeg


This is the Chandox ((after adding shop-made adjustable chuck-stops):

36689799061_58c80b56e8_k.jpg


Compared to my Bison 6" (on the rotary table), the Chandox is every bit as good in accuracy and build quality. Two years later, I tried to buy a second one from Matt and he said he could no longer source from Chandox. You might ask Matt how his current 3-jaw adjust-true from Taiwan compares to the Chandox. Don't expect a 3-jaw scroll chuck to give you repeatability tolerances better than 0.003" TIR - for that you need and Adjust-Tru type.

At some point, you are likely to want a collet chuck (either 5C or ER40) for your lathe. Read the attached before deciding.
 

Attachments

  • About R8 ER and 5C Collets.pdf
    1.7 MB · Views: 165
I also measured the 3 jaw chuck with a 1/2" drill blank inserted. This is an economy chuck, so I was not expecting much of it. It is nearly 0.004".... So I will be shopping for a good Asian made replacement. Shars has some options.
You cannot assess the accuracy of a 3 jaw chuck by measuring runout on a pin held in the jaws. This is not how a 3 jaw works. A 3 jaw is intended for first operations work so you need to chuck something in the chuck and turn it, then measure the runout of that turned piece without removing it from the chuck. It will be zero or should be unless something is seriously wrong with the chuck.

You also do not need a set-tru or adjust-tru chuck unless you are doing multiples of a given diameter in a second operation.
 
You cannot assess the accuracy of a 3 jaw chuck by measuring runout on a pin held in the jaws. This is not how a 3 jaw works. A 3 jaw is intended for first operations work so you need to chuck something in the chuck and turn it, then measure the runout of that turned piece without removing it from the chuck. It will be zero or should be unless something is seriously wrong with the chuck.

You also do not need a set-tru or adjust-tru chuck unless you are doing multiples of a given diameter in a second operation.
Mikey speaks the truth here. A 3-jaw is unlikely to provide repeatability to under 0.003” TIR remounting the same material. For tighter TIR you will need a Set-Tru and be willing to dial it in, or use a 5C or ER collet chuck.
 
You cannot assess the accuracy of a 3 jaw chuck by measuring runout on a pin held in the jaws. This is not how a 3 jaw works. A 3 jaw is intended for first operations work so you need to chuck something in the chuck and turn it, then measure the runout of that turned piece without removing it from the chuck. It will be zero or should be unless something is seriously wrong with the chuck.

You also do not need a set-tru or adjust-tru chuck unless you are doing multiples of a given diameter in a second operation.
I understand. I would lose concentricity only when I take the turned part out of the chuck. I have occasionally marked the part and one jaw so I could get it close when returning the part to the 3 jaw chuck. It has been a while since I had a lathe, so I will have to do some reeducation. Thanks for that.
 
I do have the P.M. 5C collet chuck. I installed it and indicated it in to about 0.0005". I think I can get it closer when the time comes to use it. I also checked spindle play by pulling up and down on the chuck with my hand. I am getting about 0.0005" of play as I deflect it with hand force. What should I expect for spindle play in the PM1236T lathe?
 
Back
Top