PM 1127VF LB
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StrikerDown
Enlightened
It looks like a sweet little lathe, especially the LB model, having the bore diameter of larger machines (Same bore diameter as my PM 1440!) makes it pretty versatile for a smaller package. It won't have the power or rigidity of the larger machines but for a flashlight hobby it looks quite capable. Of course as always I recommend buying the largest machine you have space and budget for... but that's just me!
Al Combs
Enlightened
- Joined
- Jul 2, 2007
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Its one serious downside is to change gears for different threads requires gloves, time and some serious head scratching. A 12x36 just requires a few twists of the knobs.🙂 Not counting the switch from 120 to 127 tooth gears for the change from imperial to metric.
BVH
Flashaholic
Las3r, join this Yahoo Group. 80% of it is info on the 1127.
http://groups.yahoo.com/group/bluemachining/messages
http://groups.yahoo.com/group/bluemachining/messages
precisionworks
Flashaholic
Just a little OT but ........
CNC lathes cut both ISO threads & metric threads with no change gearing because the leadscrew & spindle can be adjusted for any pitch.
Some older American made machines cut all ISO threads without gear changes but cut no metric threads.
Some older Euro lathes cut all metric threads without gear changes but cut no ISO threads.
A modern manual lathe will cut both ISO & metric threads but at least 3 gears have to be changed. I've seen no non-CNC lathe that cuts all the common ISO & metric threads without changing at least 3 gears.
Al Combs
Enlightened
- Joined
- Jul 2, 2007
- Messages
- 872
If I could ask a quick question. If the 120 and 127 tooth gears count as two, what is the third?
Thanks Barry
gadget_lover
Flashaholic
The key phrase here is "cuts all the common threads".
My lathe will cut 8 different threads at a time without changing a gear. I just move a lever on the gearbox. If I change one gear I get a choice of 8 other threads. Change a different gear and I get yet another 8 choices.
In essence, you typically have change gear A driving the stacked 120/127 gear which drives change gear B which drives the 8 position gear box.
I can get any choice of threads by changing as few as zero gears or as many as two. I do not count the 127/120 gears since they stay in position and you chose whether or not they are used in the drive train.
Daniel
My lathe will cut 8 different threads at a time without changing a gear. I just move a lever on the gearbox. If I change one gear I get a choice of 8 other threads. Change a different gear and I get yet another 8 choices.
In essence, you typically have change gear A driving the stacked 120/127 gear which drives change gear B which drives the 8 position gear box.
I can get any choice of threads by changing as few as zero gears or as many as two. I do not count the 127/120 gears since they stay in position and you chose whether or not they are used in the drive train.
Daniel
precisionworks
Flashaholic
I can cut 4 thread pitches using two small gears + the 120/127.
Al, in the chart above look in the upper box of numbers and there are two gears that are always changed + the 120/127. A 24 tpi was cut recently & that required 56t on top, 120/127 in the middle & 54t on the bottom. On a good day it takes 20 minutes, dropping parts into the abyss often adds another 10-15 minutes 🙁
precisionworks
Flashaholic
FWIW Matt uses the term "variable speed" and not variable frequency. He states that the motor is 120 volt 1ph & that eliminates the the use of a VFD - which can only be used with a 3ph motor.
I'm guessing that he uses a DC motor controlled by a DC motor drive & there's nothing wrong with that - DC drives were the king of variable speed for many years. The development of low cost AC micro drives has taken a big chunk of the DC drive business. Manufacturers still use DC drives when trying to stay at a price point as it is a little less money than a VFD.
Cost aside the AC drive (vector drive) will outperform the DC drive in most machine tool applications.
I'm guessing that he uses a DC motor controlled by a DC motor drive & there's nothing wrong with that - DC drives were the king of variable speed for many years. The development of low cost AC micro drives has taken a big chunk of the DC drive business. Manufacturers still use DC drives when trying to stay at a price point as it is a little less money than a VFD.
Cost aside the AC drive (vector drive) will outperform the DC drive in most machine tool applications.
I had the PM1127VF-LB lathe and just recently got a PM1236. I also thought that changing gears wasn't that big an issue but it is. You have to change gears to cut the threads and then change gears go have known feeds. The gears need to be honed out as they are to tight a fit. The pot aluminum bushings are crap and break at the most inoperatune times. The spindle is kind of a L1 spindle but it's not. It has no taper on its snout. Changing chucks kind of sucks and they are held on by a stud and nut. And the most important thing is the power. It didn't have it for me. I cut a lot more steel than aluminum and I just didn't have the power to take over .025" cuts and those had to be done at a very slow feed. Now it is a good lathe but it just doesn't deliver for me.
Now the PM1236 is another story. It is a lot louder than the 1127 and weights more than 2x as much. I did a cut in a test piece of 1.5" steel and with a carbide tool I took a .05" DOC (.1" diam reduction) at .008"/rev feed at 550 RPM and it blew right through it with no problem. Their was about 5HP available for the cut through the speed reduction gear box. At 700 RPM is where it started to max out at .1" @ .008"/rev feed. But also their was maybe 3.5HP for the cut. Now I don't have to change gears for most threads and if I do they are much easier to change and require no modification to use. Also the fit and finish on the PM1236 is better than the PM1127. Their was no burrs that had to be removed and both the cross slide and compound are hand fitted (rather poorly but still hand fitted) and used tappered gibs instead of the straight gibs on the 1127.
I highly recommend you look at the PM1236. I did a lot of work on the PM1127 but just got tired of changing gears to do single point threading. If I was able to afford the 1440 I would have gotten it. The biggest hurdle is power requirements. The PM1236 is a 220v 2HP machine and the PM1127 is a 110v 1HP machine. And the PM1127VF does use a DC motor with a speed control. When you are turning at a low speed you loose power so at say 400 RPM you have maybe less then 1/2 HP available. With the PM1236 it uses a gear reduction as so you have more power at slower spindle speeds. The best is a VFD on a 3 phase motor on a gear head lathe. You get better surface finish and variable speed, but as you slow it down past 50% power starts to drop off. I have a VFD on my Bridgeport and it really is nice not to have to change belts to change spindle speeds.
And in parting where you want to put it will make a difference as well. The PM1127 can be taken apart and 2 people can easily put it in a basement. The PM1236 is a little heavy for that. It could still be done but would require some rigging to get it down a flight of stairs. I don't like dragging chips in the house so the basement was a no go for me. I have all my machines in my garage. Currently I only have 1 3ph machine and 2 1ph machines. I eventually want all of them on 3ph power. The PM1236 could do with a 3HP 3ph motor, but as delivered it is a very nice machine.
Edit: I forgot about the spindle bore. It's not 1.5". It's like 1.495 or something like that. Which means it actually needs to be opened up to 1.505 to pass 1.5" stock through it. But opening it up isn't the easiest thing to do. I'm going to try using a tool post grinder with a long arbor that I'll make to see if I can't enlarge it to just over 1.5" so I can pass 1.5" stock through it like I had envisioned.
Now the PM1236 is another story. It is a lot louder than the 1127 and weights more than 2x as much. I did a cut in a test piece of 1.5" steel and with a carbide tool I took a .05" DOC (.1" diam reduction) at .008"/rev feed at 550 RPM and it blew right through it with no problem. Their was about 5HP available for the cut through the speed reduction gear box. At 700 RPM is where it started to max out at .1" @ .008"/rev feed. But also their was maybe 3.5HP for the cut. Now I don't have to change gears for most threads and if I do they are much easier to change and require no modification to use. Also the fit and finish on the PM1236 is better than the PM1127. Their was no burrs that had to be removed and both the cross slide and compound are hand fitted (rather poorly but still hand fitted) and used tappered gibs instead of the straight gibs on the 1127.
I highly recommend you look at the PM1236. I did a lot of work on the PM1127 but just got tired of changing gears to do single point threading. If I was able to afford the 1440 I would have gotten it. The biggest hurdle is power requirements. The PM1236 is a 220v 2HP machine and the PM1127 is a 110v 1HP machine. And the PM1127VF does use a DC motor with a speed control. When you are turning at a low speed you loose power so at say 400 RPM you have maybe less then 1/2 HP available. With the PM1236 it uses a gear reduction as so you have more power at slower spindle speeds. The best is a VFD on a 3 phase motor on a gear head lathe. You get better surface finish and variable speed, but as you slow it down past 50% power starts to drop off. I have a VFD on my Bridgeport and it really is nice not to have to change belts to change spindle speeds.
And in parting where you want to put it will make a difference as well. The PM1127 can be taken apart and 2 people can easily put it in a basement. The PM1236 is a little heavy for that. It could still be done but would require some rigging to get it down a flight of stairs. I don't like dragging chips in the house so the basement was a no go for me. I have all my machines in my garage. Currently I only have 1 3ph machine and 2 1ph machines. I eventually want all of them on 3ph power. The PM1236 could do with a 3HP 3ph motor, but as delivered it is a very nice machine.
Edit: I forgot about the spindle bore. It's not 1.5". It's like 1.495 or something like that. Which means it actually needs to be opened up to 1.505 to pass 1.5" stock through it. But opening it up isn't the easiest thing to do. I'm going to try using a tool post grinder with a long arbor that I'll make to see if I can't enlarge it to just over 1.5" so I can pass 1.5" stock through it like I had envisioned.
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precisionworks
Flashaholic
To open the 1.495" bore the best bet is a carbide tipped chucking reamer. About $150 on McMaster & 1/3 of that if you can find the size on eBay. Shank is only 12.5" long so you have to turn an extension. Not a hard job as the reamer shaft is unhardened (usually). Run the spindle about 50 rpm (or the slowest speed closest to 50). Pour all the oil you can on the reamer, flood the bore with oil, feed briskly for about 2" & withdraw with the spindle still turning. Clean reamer, clean bore, relube, go back in and advance another 2", etc.
Honing with a coarse ball hone will open the spindle another .001" or more depending on how long you hone.
Honing with a coarse ball hone will open the spindle another .001" or more depending on how long you hone.
Al Combs
Enlightened
- Joined
- Jul 2, 2007
- Messages
- 872
Las3r had mentioned the ability to do Mag builds was on his list. The Mag-D on my desk at the moment is 1.553 inch. Wouldn't that make the 1.5 inch reamer a moot point? Anyway the next size up from 1-1/2 that McMaster sells is 1-3/4 or too big of a jump. MSC has listed 1.5625 and 1.6250 in chucking reamers, but they are only HSS not carbide. The same as Enco had.
I am curious about this because in some of the PM1236 threads I've seen people mentioned the spindle being large enough to do Mag-D's. I guess I always figured there was some kind of rounding error in the Mag's favor. Those 6 inch Bison chucks the two Wills use could just about swallow a 2D whole. If it's more than that, wouldn't you just use a steady or a big live center in the tailstock? Depending of course on what you were doing. I guess if you want to re-thread a 5-1/2 Mag-D you need a PM1440.
I am curious about this because in some of the PM1236 threads I've seen people mentioned the spindle being large enough to do Mag-D's. I guess I always figured there was some kind of rounding error in the Mag's favor. Those 6 inch Bison chucks the two Wills use could just about swallow a 2D whole. If it's more than that, wouldn't you just use a steady or a big live center in the tailstock? Depending of course on what you were doing. I guess if you want to re-thread a 5-1/2 Mag-D you need a PM1440.
A reamer was one of the idea's I had thought of. I think I might even be able to pick one up for not to much. I'm going to start looking around for one. If I can pick one up for around $15 it definitely be the way to go. You for sure couldn't hurt the current surface finish of the bore. Also it is a good idea to pick up a 5MT dead center for either lathe. Less error not having to use an adapter for 5MT-3MT when you are working between centers.
BVH
Flashaholic
I bought a carbide tipped Bison 5MT dead center and it does not seat in the spindle bore. I really did not fully investigate why. (I had just got the machine as was still setting it up) But I remember looking in from the drive pulley side and seeing all kinds of daylight.
BVH
Flashaholic
I don't have any 3 or 4D mags but here's some Mag 2D and simulated 3D & 4D shots in my 1236. 2D body without tailcap and head is recessed 2" behind face of chuck jaws (3-jaw) when push into spindle as far as it will go. With 1 additional battery placed against face of body, face of light body would be about 5/8" out beyond jaw face and with 2 additional batteries, it's out about 2 7/8".
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i would love to get a bigger lathe than the 1127 LB but that's all i can fit in the space i have 🙁
So can the 1127 LB even fit a 2D mag inside ? i hate to purchase one and find out it will not fit a 2D mag...
With the 1127LB im just planning on making my own heatsinks,boring out my flashlights and learning how to do threads ect....i don't think ill be cutting steel may be copper if it can lol
sounds like the 1127 is a POS.... but i dont no what else to buy in my budget/space i have besides a little 7x12 lathe lol
So can the 1127 LB even fit a 2D mag inside ? i hate to purchase one and find out it will not fit a 2D mag...
With the 1127LB im just planning on making my own heatsinks,boring out my flashlights and learning how to do threads ect....i don't think ill be cutting steel may be copper if it can lol
sounds like the 1127 is a POS.... but i dont no what else to buy in my budget/space i have besides a little 7x12 lathe lol
BVH
Flashaholic
I just asked the question on the bluemachine forum I linked above. Not sure if you have to register or not to just view but here's the link:
http://groups.yahoo.com/group/bluemachining/messages
There's a number of people happy with their 1127 machines, mostly 1127, non-large bore because those are fairly new and the latest shipment just went out to some waiting about 10 months. I believe Matt (Machinetoolsonline) said he actually had a few left over to keep in-stock, which, I guess, is rare these days.
http://groups.yahoo.com/group/bluemachining/messages
There's a number of people happy with their 1127 machines, mostly 1127, non-large bore because those are fairly new and the latest shipment just went out to some waiting about 10 months. I believe Matt (Machinetoolsonline) said he actually had a few left over to keep in-stock, which, I guess, is rare these days.
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