Setting-up the PM 1236-T Lathe

3 tenths is as good as any millwright will be able to obtain. Well done!
 
Thanks Dabbler. The 4JC and Collet Chuck did not fair as well, but pretty close. It really is much better than I need for what I am doing but it's nice to "know" your machine. Not in the Biblical sense, of course, although we are spending a lot of time together these days...
 
First...congrats on the new addition to your family!

Second...don’t waste your time chasing a couple of tenths...that time is better spent with the family!

Third...great write up and well done in achieving the accuracy you worked hard for!


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Congrats, TK, and a very hearty welcome to Grace!! Hope Mrs. TK is doing well.

First, I have no idea how your lead photo relates to whatever is going on inside your head but I have to say that if it was me, I would tell the forum to go to hell while I fell in love with my brand new daughter! Man, I would spoil that little girl - lucky she isn't mine.

For what it's worth, I agree that it makes more sense to align the headstock with the ways and then align the headstock to the tailstock. That's the way the rest of the world does it, at least to my knowledge. Maybe Matt knows something the rest of us don't.

As for why you got a reverse taper, I'm not sure. You've created a constrained system with a follow rest and are taking a healthy cut with a carbide insert tool on a hardish work piece so I have no idea what the results mean. If you had taken a 6-8" long, 1" OD piece of soft steel, like 12L14, and indicated it to zero in a 4 jaw, then used a well ground and really sharp HSS tool with a 1/64" nose radius( to minimize deflection) to take a 0.002" depth of cut with no other support or constraints on the rod then I would say the test would probably reflect your headstock alignment.

You're right in that we can drive ourselves crazy chasing things down to tenths. Most of the time it just isn't necessary. However, in the case of headstock alignment, it isn't a bad idea to get it as close to zero as you can because you will use that to align the tailstock.

Now, I have to ask you, why are you still reading this? Go kiss your daughter!!
 
Mikey, thanks for your well wishes regarding Grace. She’s a cutie and our granddaughter. If Mrs TK had given birth to her we would have named her Miracle.

Alright, I agree, the lead Photo is a bit cryptic. It is supposed to be like the other lead shots taken from the Headstock and show that this view from “Headstock” is a bit askew and looking slightly to the right and that if you follow it to the horizon(tailstock) you end up way over to the right by the sunset instead of where the tracks lead. It’s a stretch, forget I mentioned it.

Happy the rest of the world aligns centers after the Headstock. Makes sense to me.

Going to try a couple things this weekend to try to figure out reverse taper but am not going to spend too much time on it. I will keep you posted.

As always, I appreciate your input!
 
Okay, not knowing your age I assumed too much but congrats anyway! I loved it ... Miracle.

I have no grandchildren but if my son ever gives me a grandaughter she will be cherished and spoiled beyond belief.
 
All, I deleted post 189(cutting tests using the 4JC and collet chucks). Using a 12” rod and a follow rest introduced too many variables and just isn’t the right way to do it-Newbie mistake. I apologize to those of you that waded through it but I don’t want it to be a perennial source of confusion for people that may look at this thread in the future. For now just look at post 178 for Headstock alignment using the MT5 test bar, it is accurate. Sorry for the confusion. TK
 
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Before I go on to the next section on Aligning Centers I would like to make a comment: If I were to do the cutting tests again, and I probably will, I would suggest that one simply do the standard 6”, two collar test. I thought that using a 12” rod would give me more accuracy but I think just the opposite is true since it requires a follow rest to reduce vibration to get a smooth cut and it increases deflection; both of which introduce unwanted variables.

Lesson: a longer rod is not always better
 
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