Setting-up the PM 1236-T Lathe

mikey said:
I am not understanding something - what is the purpose of the jack screws? They are pointing down with nothing under them so I'm confused.

I find it interesting that you have sought to isolate the lathe from the ground via the mounting plate and rubber isolation pads. Most set ups seek to make the connection to the ground as solid as possible to enhance rigidity. Can you expand on your thinking here? Not a criticism; mostly just curious.
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Mikey, the baseplate is threaded and the jack screw goes into those threads. When the screw is advanced upward it lifts that portion of the tailstock footing. For example, when I was leveling the lathe the side of the tailstock toward the operator was a bit low. I loosened the nut on the anchor bolt, lifted that corner by advancing the jack screw then re-tightend the nut on the anchor bolt. I repeated this is small increments until the lathe was level, then I tightened the lock nut on the jack screw. This took a total of about a quarter turn on the jack screw. The pointed end of the jack screw is not used. I used jack screws because they have a nice fine 1/2-20 thread, they are hardened and I can use the small hardened rod that comes with them to make adjustments by hand. Also, they are only $8 from Starrett. I didn’t know Starrett made anything for $8. I hope this helps.
 
Titanium Knurler said:
Mikey, the baseplate is threaded and the jack screw goes into those threads. When the screw is advanced upward it lifts that portion of the tailstock footing. For example, when I was leveling the lathe the side of the tailstock toward the operator was a bit low. I loosened the nut on the anchor bolt, lifted that corner by advancing the jack screw then re-tightend the nut on the anchor bolt. I repeated this is small increments until the lathe was level, then I tightened the lock nut on the jack screw. This took a total of about a quarter turn on the jack screw. The pointed end of the jack screw is not used. I used jack screws because they have a nice fine 1/2-20 thread, they are hardened and I can use the small hardened rod that comes with them to make adjustments by hand. Also, they are only $8 from Starrett. I didn’t know Starrett made anything for $8. I hope this helps.
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Mikey, with regards to your second question, this stand is constructed in such a way that I don’t think there is anything I can do to make it rigid so it will always twist when it is moved. If it twists and is rigidly attached to the lathe it will twist as well requiring re-adjustment of the lathe. I wanted to try to avoid this, so I isolated the two, somewhat, from one another. The stand can twist when moved while the lathe stays rigidly attached to it’s baseplate. That’s the concept anyway and so far it appears to be working since I have not needed to re-adjust it yet. I hope that answers your question.
 
Okay, I get the idea. The jackscrews adjust the level relative to the baseplate, which is then isolated from the cabinet itself. Novel idea; you have to let us know if it provides enough rigidity in use. I have to admit that this is the first time I've seen this done.
 
P. Waller said:
I suspect that this will be wildly entertaining, I am 60 years old so will likely not live long enough to see the end of this "installation".


Good Luck
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I dunno', I'm just enjoying the journey. This guy is relatively new to the hobby and is sharing his unique approach to setting up his lathe. I'm finding it interesting; it shows that he actually thought about stuff before doing it. He is also answering my stupid questions about why he is doing this or that, and somewhere in here is an idea that will help some other new hobby guy.

So, TK, bring it on. I, for one, am enjoying this well-documented process.
 
mikey said:
Okay, I get the idea. The jackscrews adjust the level relative to the baseplate, which is then isolated from the cabinet itself. Novel idea; you have to let us know if it provides enough rigidity in use. I have to admit that this is the first time I've seen this done.
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Mikey, you got it!

As far as rigidity is concerned let me show you some vibration and sound measurements I gathered on the lathe and stand. First I will describe the set-up then the results.

I used a vibration meter at the at the headstock, carriage and stand to measure velocity in mm/s; measured the sound at .6 meters from the headstock(my head position) and rpm using a mechanical rpm meter:

104E7526-CDAD-4937-9314-E66B9033A724.jpeg. DF3C9510-CBF5-4F85-9247-85322715E599.jpeg

3693EE85-ACB6-4415-ACC1-5B1AE391D951.jpeg. 7E6C3FE8-6B6B-4B93-BF0C-31F013A5A8C6.jpeg

Here are the results:

Lathe Vibration Table001.jpg

Here is an ISO vibration table(the PM 1236-T is considered a Class I small machine):

902EA6B8-E14B-49AF-8403-A42A999ADF41.jpeg

I think you can see that the vibration readings are excellent at the headstock until you get up over a thousand RPM but even these are considered satisfactory. Vibration is very low, almost unmeasurable, at the carriage and stand at all RPM. The readings are similar with various chucks but I have not tried an unbalanced 4JC as Mitch Alsup suggested early on in this thread. This is not what I usually do with the lathe but I will give it a try and let you know.

Now for the sound. The lathe goes from “piano practice” to a “garbage disposal” as the RPM increases. Not sure how this compares to other lathes but now that we have “numbers” and test parameters someone with a dB meter can compare.

54EF78D7-3944-4971-A3B8-230E666A417A.jpeg

The reason I bothered to take these measurements was that I was concerned that since this was “novel” set-up I feared that there might be an RPM setting that matched the harmonic of the machine and the damn thing would fly out the window. Fortunately, this did not happen.

I hope this helps.
 
mikey said:
I dunno', I'm just enjoying the journey. This guy is relatively new to the hobby and is sharing his unique approach to setting up his lathe. I'm finding it interesting; it shows that he actually thought about stuff before doing it. He is also answering my stupid questions about why he is doing this or that, and somewhere in here is an idea that will help some other new hobby guy.

So, TK, bring it on. I, for one, am enjoying this well-documented process.
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Mikey, you are correct, I am new to this. I am still in the period of magical thinking where almost anything is possible and I am unincumbered by dogma. It is also about the journey for me. I derive a great deal of pleasure thinking about these things; It can be a wonderful distraction and stress reliever. It is not about the fish, it’s about the fishing. Although I get pretty ****** off when I don’t catch any fish. Seriously, I thoroughly enjoy the challenges of the hobby and the discussions that ensue, even yours P. Waller if you are still alive!
 
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