PM1340GT Lift Using a D-RIng and Old Base Cabinet Mods

mksj

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There are various ways to lift the lathe, on the smaller lathes it usually involves some form of belting across the Bed or through the bed. The manual suggests two belts perpendicular to the bed with planks under the bed. When I originally put my lathe on the stands I used a 2 ton belt through the bed, with a strap through the spindle and another to the tailstock end of the machine so it could be leveled. I am always concerned that when you belt under the machine, that if it is not balanced well to start with, that the belts can slip or the machine can roll.

Other lathe makers recommend using an eye bolt or D ring bolted through the center of the bed with plates on top and bottom of the bed.
Eye Bolt Lathe Lift.jpg


Since I had the old PM1340GT cabinets, I had planned on beefing up the cabinets bases and also adding some 1/2" plates to the top of each cabinet. On the Headstock cabinet I built supports under each cabinet using 1/2" steel x 3" wide stock and tapped 5/8" threaded holes for 4 new steel mounting feet. L taps are welded on either side and bolted through into the cabinet with 1/2" bolts in addition to the original foot hole in the center.
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20170203_173357.jpg


In order to install the 1/2 steel plates on the top of the cabinet, I needed to lift the machine off the base. I opted to use a D-Ring (Jergens #23516 rated at 4000lbs) support through the bed. I used a 9" x 5/8" Grade 9 bolt with heavy washers instead of the shorter bolt that comes with the lifting ring. The top plate is 1/2 aluminum x 4" wide by 12" long. It does not sit on the bed rails, but slides under the rails and slide in through the tailstock end. I rounded the edges on either side to match the contours of the bed, and then added thin neoprene rubber.
D-Ring Lift.jpg
Grade 9 Lift Bolt.jpg


The bottom plate was 1/2" x 5" wide by 10" long and sits perpendicular to the bed. I also did some slight profiling so it locks into the underside of the bed and then added a neoprene layer. I was able to pick up all the parts as remnants or via eBay, making is much more affordable.
Bottom Lift Plate.jpg



I still use Jack straps to allow leveling along the length of the machine, but you can still get some twisting of the machine backwards, especially if you use a heavy (non-stock) motor which is what I use. Overall, it was much easier and quicker to do the lift with the D-Ring, but still a two or 3 person job to get the lathe in position and get the bolts aligned in place. I had Paco (firestopper) and his son help me, and want to thank them for making this a much easier job.

I strongly recommend using sealant around the bolt holes, I originally used silicone sealant and it did not hold up well to the oils, I would recommend using a polyurethane sealant instead.

After 1/2" plates were installed and lowering the 2 ton hoist.
Lift.jpg


The machine was then re-leveled. The end result was a much more stable machine, but there is a vibration node at around 600-700 RPM and around 1200-1300 RPM, and because I switched from Mason feet which absorbed some of this vibration to solid feet, I ended up with more shaking of my DRO (but less machine movement). The fix for my ES-12 DRO display was adding a back plate in the control cabinet for the DRO mount and building a heavier DRO support mount. This is less likely to be a problem with the newer ES-12B because of a number of design changes.

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Mark,
Great ideas at play, thanks for sharing and putting them here so folks can borrow them.
 
Good job Mark. I did a similar setup when moving the lathe from the old stand to the new. I still used a strap but used a 1/2" plate under the bed (like yours) that I welded a piece of square tubing to. The tubing fits into the recess in the bed, locking the plate in position. I left enough wiggle room to allow some movement so I could fine tune the balance. I also used extra straps to stabilize the load as you did.

I would say your solution is safer than mine but if you are careful it works great.
lift plate.JPG
 
Good job on a safe lift. I used the method shown in the manual. It worked ok but I just needed a vertical lift off the pallet, then rolled the new stand underneath on furniture dollies. The methods Mark and Dan show in this thread are highly superior.

The scariest part for me was controlling the decent. My hoist has a sticky valve .
 
Mark, I forgot to add that the mods you did to the stock stand were the same ones I was going to do before switching gears and building a new stand. The reinforcements are a great improvement.
 
Mark,

Like the lift, it seems that the D ring concept gives you more capacity with the hoist too. I'm planning for arrival of a PM1236 so I'm collecting ideas and materials.

Do you have any pictures (or advice) on adding the plate to the top of the stands? I have some 1/2 plate sitting around but I'm uncertain about the benefit of that without tying it into a fixed base. If you can add any comments on the before and after I would be interested to hear.

I'm definitely adding a base to mine both to add a little height and some rigidity to the whole set up. Right now I'm thinking a GaryK style base even though I realize I will probably have to level at the lathe instead of working out any twist with the feet on the base.

This is my first metal lathe so any educational commentary will be appreciated.

Thanks!
 
Hi BFHammer,
I am not aware of any problems with the base on the PM1236, and I believe it is setup for 6 leveling feet. The older 1340GT had 4 leveling feet so there was some rocking or flex on the headstock cabinet which was also thinner sheet metal. So I think that the addition of 4 leveling feet instead of 2 on the headstock cabinet and using a total of six 5/8" shank feet made the biggest difference. The upper plates are bolted between the base and the lathe using the mounting bolt holes. The plates made some improvement, but not significant in my case (I also have addition bracing between my cabinets). The other problem one has is that the more one makes the base rigid, you still can get some flex in the cabinets. In my case the machine is now much more rigid and I expect the bed will stay level, but other parts can still vibrate at their resonant frequency. When going to a VFD, you are more likely to notice this, because you have an infinite range of speeds, vs. fixed speed gear box.

I think a rigid base attached to both legs would go a long way and using 6 leveling feet. I Would rigidly mount your base to the cabinets by bolting or welding, and add some gusseted brackets a bit wider than the base to attach the leveling feet. Adding a slightly wider stance will go a long way to making it more rigid. Another trick I use on speaker stands is to fill the tubing with concrete to dampen and add mass. But makes it hard to move. Do not overthink it, you might start out with what you have and see how it works, then go from there. The only other factor that can make a significant difference in surface finish is going to 3 phase, an RPC which is easy and less expensive then the VFD route, a VFD gives more control.

On the D-Ring it was more readily available than an eye bolt of similar capacity, The D-Rings come in different capacities so a 1 or 1.5 ton would be more than adequate, it was just that I was able to pick this up very inexpensively on eBay, and it has a bit more height (length). I also wanted to be able to use a large shank bolt.

Just checked out the base you mentioned, that would work well, but I would use 4 feet on the headstock end and two on the tailstock. I also would use solid feet which are less likely to get any settling with time.
http://www.hobby-machinist.com/threads/another-pm1236-install.22799/

Mark
 
Last edited:
Mark,

Thanks for the reply - all helpful information.

I am not going to get too carried away - I will start with the base stand which will give the small height lift i need and some rigidity. It's also an easy project and will get me up and running quickly once my lathe arrives.

It's exciting seeing all the great things you guys do with your machines. I can't wait to get mine installed and get to making some chips!
 
Hi,
Here's my two cents worth. Lifting plate is two pieces of 10mm plate,(cut from one piece as it was all I had to hand), two 3/8" countersunk grade eight machine screws and a 5/8"W lifting eye. plate only just slides in from the gap with a thou' clearence each side. The bit of wood is scrap soaked in epoxy and thumbwheel is just to hold it in place.
My lathe weighs in at 650Kg dry and this lifts it with ease on cabinet with coolent tank full and all oils.
Plate is located above 1st web from headstock. Tailstock at extreme end of bed. Apron used to adjust balance.
What I like is no mucking around with strops, wood packing ect. K.I.S.S.

Cheers,
Barry.

Lathe Lifting plate.JPG
 
Thanks for that!

Squire

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