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- Jan 18, 2018
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That's correct.
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PM-1236-T 12″x36″ Ultra Precision Lathe-Good Machine?
- Thread starter Titanium Knurler
- Start date
- Joined
- Dec 7, 2015
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- 519
Thanks again, Titanium Knurler and gman10259- not that I didn't believe you, gman. Simple curiosity about how this worked.
I can't find a "max center height" for QCTPs, but assume there is no actual max- rather only what the operator is comfortable stacking up. LMS has some specs about min center height for AXA vs BXA:
And Aloris has specs about tool holder size:
So I guess we can subtract the B dimension from the A dimension on the turning holder to get the height of the lower block. Then we can add in the 1/2" tool height to get the min height of the cutter relative to the bottom of the tool holder block bottom. For the AXA holder, that would be (.9375 - .5) + .5 = .9375 inches**. Taking this measurement and subtracting from the lathe's center height would indicate how low the tool would be from the center height at the lowest possible position on the tool post***. In this case, looks like the center height for the PM-1236-T is 1 7/32" or, 1.21875" so the tool on an AXA holder would fall (1.21875" - .9375") = .28125" below center height. Or in other words, using an AXA tool post would require raising the tool by .28125". My AccuSize tool holders seem to have at least .5" of adjustability and therefore indeed the AXA size should work just fine on this lathe (as we already knew from gman). That was interesting to investigate though. I wasn't sure how all this worked... Instead of specifying some reasonable guideline, Aloris simply states to email them and ask.
** I do realize that the A dimension would seem to imply the final height, however it should be noted that not all AXA tool holders have an exact 1/2" B dimension. In fact, my Accusize #250-001 holders seem to have closer to 9/16" capacity. Therefore it wouldn't always be true that the A dimension states the tool height relative to the bottom of the holder.
*** This also assumes that the bottom of the tool holder block could potentially rest on the compound at the lowest position of the adjustment screw. I'm not in front of my lathe at the moment, but I suspect that this might not be entirely true; there is probably a built in stop on the tool post disallowing the tool holder block from touching the compound. Therefore whatever this built in space is, it would be subtracted from the final calculation above.
I can't find a "max center height" for QCTPs, but assume there is no actual max- rather only what the operator is comfortable stacking up. LMS has some specs about min center height for AXA vs BXA:
And Aloris has specs about tool holder size:
So I guess we can subtract the B dimension from the A dimension on the turning holder to get the height of the lower block. Then we can add in the 1/2" tool height to get the min height of the cutter relative to the bottom of the tool holder block bottom. For the AXA holder, that would be (.9375 - .5) + .5 = .9375 inches**. Taking this measurement and subtracting from the lathe's center height would indicate how low the tool would be from the center height at the lowest possible position on the tool post***. In this case, looks like the center height for the PM-1236-T is 1 7/32" or, 1.21875" so the tool on an AXA holder would fall (1.21875" - .9375") = .28125" below center height. Or in other words, using an AXA tool post would require raising the tool by .28125". My AccuSize tool holders seem to have at least .5" of adjustability and therefore indeed the AXA size should work just fine on this lathe (as we already knew from gman). That was interesting to investigate though. I wasn't sure how all this worked... Instead of specifying some reasonable guideline, Aloris simply states to email them and ask.
** I do realize that the A dimension would seem to imply the final height, however it should be noted that not all AXA tool holders have an exact 1/2" B dimension. In fact, my Accusize #250-001 holders seem to have closer to 9/16" capacity. Therefore it wouldn't always be true that the A dimension states the tool height relative to the bottom of the holder.
*** This also assumes that the bottom of the tool holder block could potentially rest on the compound at the lowest position of the adjustment screw. I'm not in front of my lathe at the moment, but I suspect that this might not be entirely true; there is probably a built in stop on the tool post disallowing the tool holder block from touching the compound. Therefore whatever this built in space is, it would be subtracted from the final calculation above.
- Joined
- Jan 18, 2018
- Messages
- 314
Wildo, your reasoning and math look good to me but I am a newbie. I think your best confirmation that your AXA QCTP will work is Gmans statement that it. So I wouldn't let that keep your from getting the 1236-T. I think you will be very happy with it.
I had the AXA QCTP tool post from my previous lathe along with Accusize Tool Holders. I just put it on the 1236-T lined up the tool to my live center on the tail stock and started making chips.
Precision Mathews website has a description in their AXA QCTP below.
Sizing:
(This tool post will generally fit lathes from 10″ to 12″ Swing, please check carefully as shown below)
Measure from the top of your compound slide, where the tool post sits, to the center line of the spindle/work piece (Using a center in the tail stock to find this is normally the easiest way) For this AXA Tool Post Set, you will need a minimum of 1″ from that measurement, up to a maximum of about 1-3/4″. If it is more than this 1-3/4″, you want to use a larger tool post to fit it properly.
Most stuff I've seen for the AXA size tool post state 10 - 12 inch lathes.
Precision Mathews website has a description in their AXA QCTP below.
Sizing:
(This tool post will generally fit lathes from 10″ to 12″ Swing, please check carefully as shown below)
Measure from the top of your compound slide, where the tool post sits, to the center line of the spindle/work piece (Using a center in the tail stock to find this is normally the easiest way) For this AXA Tool Post Set, you will need a minimum of 1″ from that measurement, up to a maximum of about 1-3/4″. If it is more than this 1-3/4″, you want to use a larger tool post to fit it properly.
Most stuff I've seen for the AXA size tool post state 10 - 12 inch lathes.
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- Jul 2, 2014
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- 7,594
Lathe swing has nothing to do with tool post sizing. Spindle center to top of compound dimension, location of slots in tool holders, and size of bits intended to be used are the things you need to check from the spec dimensions. Mistakes can be expensive...
- Joined
- Dec 7, 2015
- Messages
- 519
Exactly! This is why I wanted to figure out how to run the numbers in my post above...
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- Apr 22, 2018
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- 12
I'm looking into buying a PM1236 perferred model, what is the difference between the perferred model and the "T" model.
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- Jun 12, 2014
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- 4,810
The PM1236T is made in Taiwan and other than being a 1236 size it is a completely different lathe than the PM-1236. I would pull up the manuals for both and review them. Both are very capable lathes, the Taiwanese machine will have a higher level of quality and finish, it also comes with a Norton gearbox, so no change gears unless you need to do metric.
https://www.precisionmatthews.com/shop/pm-1236/
https://www.precisionmatthews.com/shop/pm-1236-t/
https://www.precisionmatthews.com/shop/pm-1236/
https://www.precisionmatthews.com/shop/pm-1236-t/
- Joined
- Jan 18, 2018
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- 314
Agree with mksj. I have had my 1236T for six months or so and have been VERY happy with it.
The 1236 Preferred has many more standard accessories that do not come with the 1236T: 4JC, steel stand (with an option for a cast iron stand which I inquired about when purchasing my 1236T but it was not available then but I would suggest you consider this if you purchase the 1236 or 1236T if it is available), QCTP with five tool holders, clutch on feedrod(standard on 1236T), micrometer stop, foot brake, coolant system and LED light(std. on 1236T). That’s a lot of options but, again, they are different machines: the 1236T is all Taiwanese and has precision Japanese spindle bearings. I guess your choice is a higher quality machine or lots of accessories. If the precision is not critical for your work and the accessories are useful for what you are planning to do get the 1236 Preferred, if precision is what you are after then go for the 1236T and add the accessories you need.
The 1236 Preferred has many more standard accessories that do not come with the 1236T: 4JC, steel stand (with an option for a cast iron stand which I inquired about when purchasing my 1236T but it was not available then but I would suggest you consider this if you purchase the 1236 or 1236T if it is available), QCTP with five tool holders, clutch on feedrod(standard on 1236T), micrometer stop, foot brake, coolant system and LED light(std. on 1236T). That’s a lot of options but, again, they are different machines: the 1236T is all Taiwanese and has precision Japanese spindle bearings. I guess your choice is a higher quality machine or lots of accessories. If the precision is not critical for your work and the accessories are useful for what you are planning to do get the 1236 Preferred, if precision is what you are after then go for the 1236T and add the accessories you need.