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How Are You Mounting Your Pm1340gt Lathe?
- Thread starter sanddan
- Start date
- Joined
- Jan 22, 2012
- Messages
- 655
Congratulations RIO! After watching the first video I felt very bad for you (and me) as it sounded like my plans weren't going to work either but the second video showing success is very encouraging. I have been convinced that the stand is the main problem with the shimmy and ringing we have been experiencing. I started along a similar path of reinforcing the stand but after thinking on it I decided to go a different direction. I am building a completely new stand using 2x2 tubing and incorporating a 44" HF tool box for storage. After seeing your results I think I'll add a feature that will allow me to bolt to the floor if I have to. Thanks very much for sharing the videos.
- Joined
- Jun 12, 2014
- Messages
- 4,810
Hey Rio,
Seems like you and Dan are having a swaying motion type of vibration, interesting solution and thank you for working it out. I still think the upper plate will add rigidity to the structure, and seems like you have a very rigid set-up. I always was puzzled about only two supports on the motor cabinet, that you could get a lot of flex between the cabinets. Since I added the 2" square tubing braces between the cabinets, I mat not see it as much. The bases are built to a price point, but I agree that a more rigid base goes a long way to getting the maximum performance out of the lathe.
On the head stock alignment, would use a 0.0001" dial indicator to check the head alignment, then check at 0 and 6" with your test bar. I would the try the 4J and check the TIR at the chuck and then at ~6-8" out. As you can get some wobble with a chuck, I check that the wobble +/- around the 0 point is the same. Then you can do some test cuts with a two ring bar. Bed twist is more of a factor further away from the chuck, I set my machine up with a 0.0005"/foot precision level, running it the full length on the carriage travel. At 6" out from my chuck dialed in to better than 0.0001" at the chuck I get about 0.0004" total TIR at 6-8" out. This is similar to what Dan had. I then aligned the tailstock so it reads within 0.0002" of what I read at the chuck, looking that the sing is the same +/- around 0. There is a point of chasing your tail with all this, when you just need to say it is good enough.
Mark
Seems like you and Dan are having a swaying motion type of vibration, interesting solution and thank you for working it out. I still think the upper plate will add rigidity to the structure, and seems like you have a very rigid set-up. I always was puzzled about only two supports on the motor cabinet, that you could get a lot of flex between the cabinets. Since I added the 2" square tubing braces between the cabinets, I mat not see it as much. The bases are built to a price point, but I agree that a more rigid base goes a long way to getting the maximum performance out of the lathe.
On the head stock alignment, would use a 0.0001" dial indicator to check the head alignment, then check at 0 and 6" with your test bar. I would the try the 4J and check the TIR at the chuck and then at ~6-8" out. As you can get some wobble with a chuck, I check that the wobble +/- around the 0 point is the same. Then you can do some test cuts with a two ring bar. Bed twist is more of a factor further away from the chuck, I set my machine up with a 0.0005"/foot precision level, running it the full length on the carriage travel. At 6" out from my chuck dialed in to better than 0.0001" at the chuck I get about 0.0004" total TIR at 6-8" out. This is similar to what Dan had. I then aligned the tailstock so it reads within 0.0002" of what I read at the chuck, looking that the sing is the same +/- around 0. There is a point of chasing your tail with all this, when you just need to say it is good enough.
Mark
- Joined
- Mar 22, 2013
- Messages
- 497
Great to see some good news!
So I am thinking it is that bottom piece on the stand that is or was flexing, where the leveling pads are mounted in.
Dan maybe just do a setup like that to save a lot of time and money in building a different stand. Unless you already started it!
Of course a nice stand with tool storage would be an excellent setup though, but just a lot of work!
Glad to see some progress on this!
So I am thinking it is that bottom piece on the stand that is or was flexing, where the leveling pads are mounted in.
Dan maybe just do a setup like that to save a lot of time and money in building a different stand. Unless you already started it!
Of course a nice stand with tool storage would be an excellent setup though, but just a lot of work!
Glad to see some progress on this!
- Joined
- Jun 12, 2014
- Messages
- 4,810
Rio, my machine belt tension bar is the same as yours, but my belt tension is a bit tighter. It has not been an issue, nor did I feel the motor vibrating when it is running. Probably even less of an issue on yours due to the motor weight. Agree it, I was a bit surprised at the play when I first noticed this, but hasn't been an issue. I may ultimately mill a new support or mill a bushing for the current support. If you did not want to remove the mounting bolt you may be able to slide a washer with a slot cur in it or use a SS lock washer by opening it and then compressing it around the bolt.
- Joined
- May 29, 2014
- Messages
- 188
Rio, how about putting some (quite a bit of) downward tension on the motor and then tighten the lower bolt. This should A) Tighten the belt, & B) Allow the tension on the belt to prevent the motor from bouncing around causing vibrations. Option 2 is to fix the arm.
Have you made any chips yet? What type of material are you using? If you can locate some, obtain some 12L14 steel and play with it. It is amazing stuff to machine. The CrapSteel sold in Lowes/Home Depot/TractorSupply/etc is generally horrible to machine.
Here is a link : http://www.onlinemetals.com/merchant.cfm?pid=9561&step=4&showunits=inches&id=265&top_cat=197
I have purchased from this vendor previously and been very satisfied.
Good luck
Jerry in Delaware
Have you made any chips yet? What type of material are you using? If you can locate some, obtain some 12L14 steel and play with it. It is amazing stuff to machine. The CrapSteel sold in Lowes/Home Depot/TractorSupply/etc is generally horrible to machine.
Here is a link : http://www.onlinemetals.com/merchant.cfm?pid=9561&step=4&showunits=inches&id=265&top_cat=197
I have purchased from this vendor previously and been very satisfied.
Good luck
Jerry in Delaware
- Joined
- Mar 22, 2013
- Messages
- 497
Hey Rio, are you actually having a problem or did you just notice it was loose? It wouldn't hurt for it to be tight, but I don't think it is doing anything is it?
Start making some chips with the machine and post some videos of that!
Start making some chips with the machine and post some videos of that!
- Joined
- Sep 13, 2015
- Messages
- 61
Fixed. Big lock washer behind the bar/bushing screw on the top. yes it was a problem. Yes it made it better. A LOT better. Thanks for the help Mark.
Had to take the top pulley off to get the bushing screw out. Had to bang the pulley off. The key was way too tight. Lop-sided actually. Filed and sanded the key a little, and the pulley slides on and off the way it's supposed to now.
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"Just make some chips" is good advice if you own a potato chip factory, not if you bought a "high-precision gunsmith" metal lathe that did by no means came plug-and-play as advertised. I've been very gracious and patient, and I appreciate Matt doing the same. But for what I paid, I should have been chambering "high-precision" barrels by now. If "chips" was my end product, I would have bought a Grizzly
yes, still smiling....
P.S. I made chips last night about 1:00. So what it was PVC
I'm already addicted. Going on 3 hours of sleep like some love-sick teenager...
Had to take the top pulley off to get the bushing screw out. Had to bang the pulley off. The key was way too tight. Lop-sided actually. Filed and sanded the key a little, and the pulley slides on and off the way it's supposed to now.
.
"Just make some chips" is good advice if you own a potato chip factory, not if you bought a "high-precision gunsmith" metal lathe that did by no means came plug-and-play as advertised. I've been very gracious and patient, and I appreciate Matt doing the same. But for what I paid, I should have been chambering "high-precision" barrels by now. If "chips" was my end product, I would have bought a Grizzly
yes, still smiling....
P.S. I made chips last night about 1:00. So what it was PVC
I'm already addicted. Going on 3 hours of sleep like some love-sick teenager...