Pm 1228-vf-lb Lathe Preparations

[Franko]

My new PM01127-VF-LB lathe is due to arrive pretty soon — maybe a few weeks. This thread will be about my preparations, set-up and general experience with this new tool.

Anyone else with a PM1127 feel free to share observations, questions or whatever. I'd like this to be a good general discussion area for that machine.

Preparations have been in planning for the last 8 weeks. Today, I think I've finalized plans for the stand. It will be a HF heavy duty 42" base tool cabinet with a welded custom wheel trolly system to lower the overall height about 4" lower than the standard wheels the cabinet comes equipped with. The tool chest is a substantial cabinet, very heavy duty and rated for about 3,000 pounds.

The top of the stand will be 2 layers of 3/4" Baltic Birch plywood with an additional piece to set the top in the recess on top of the cabinet.

Feedback is welcome.

All the steel on the trolly system will be 1/4" hot roll flats. I've devised wheel trucks for the left side that start with 3" iron wheels, bored and centered for a .5" bolt axle. The wheels are mounted on a truck that will pivot at the center on .5" bolt welded to the end part of the cabinet support. .5" leveling bolts are just inboard of the wheels for leveling the left side. I'm a little concerned that the .5" welded pivot bolt might not be enough. I'd love some feedback on that.

Here's an isometric drawing to demonstrate the concept. I didn't draw an isometric of the casters because it would a lot of effort that would serve no useful purpose.

This is a plan drawing showing the scale and overall details. Elevation view on top and plan view on the bottom. The truck is exploded off the base for clarity. The drawing left of that is the whole end assembly.
On the bottom the assembly view is a elevation view from the side.

The tool cabinet will rest on 1" x 1/8" steel angle spot welded to the rim of the stand.

The right and steerable side of the trolly will utilize leveling casters rated at 1100 pounds each. The brackets are .25" steel and gusseted inside.
This is my second area of concern, that the .25" steel will be up to the task of supporting the chest full of iron and lathe. I estimate that the total weight of the stand and lathe will around 1,000 pounds.

Below is a photo of the casters.

 

[tmarks11]

The top of the stand will be 2 layers of 3/4" Baltic Birch plywood with an additional piece to set the top in the recess on top of the cabinet.

Are you going to set the chip tray on top of the plywood?

Just keep in mind that the plywood will add some flex to your setup, although the chip tray will help spread the load of the 550# lathe over the surface, so maybe it won't affect you ability to level the lathe and zero the machine. Keep in mind that while a lathe looks like a massive chuck of cast iron, in reality the lathe bed will twist like a limp noodle.

Ok, maybe not that much, but 0.003" is way more than you want to see. One way to prevent that would be to add a layer of 1/4"-3/8" steel plate underneath the chip tray. Locally, I was quoted $150 for 24x36, 3/8", laser cut. You can probably find cheaper if you look.

 

[Franko]

Tim, the chip tray will sit on top of the plywood. Baltic birch is pretty dense plywood and the footprint on each end of the lathe will rest right over the short end edges of the toolbox, which should stabilize torquing. The footprint of the lathe at point of contact is about 7" x 10" on the headstock end and 7" x 7" on the tailstock end, so all the weight of the lathe is supported on the ends and none in the middle.

 

[Quai_Oui]

My new PM01127-VF-LB lathe is due to arrive pretty soon — maybe a few weeks. This thread will be about my preparations, set-up and general experience with this new tool.

Anyone else with a PM1127 feel free to share observations, questions or whatever. I'd like this to be a good general discussion area for that machine.

Preparations have been in planning for the last 8 weeks. Today, I think I've finalized plans for the stand. It will be a HF heavy duty 42" base tool cabinet with a welded custom wheel trolly system to lower the overall height about 4" lower than the standard wheels the cabinet comes equipped with. The tool chest is a substantial cabinet, very heavy duty and rated for about 3,000 pounds.

The top of the stand will be 2 layers of 3/4" Baltic Birch plywood with an additional piece to set the top in the recess on top of the cabinet.

Feedback is welcome.

All the steel on the trolly system will be 1/4" hot roll flats. I've devised wheel trucks for the left side that start with 3" iron wheels, bored and centered for a .5" bolt axle. The wheels are mounted on a truck that will pivot at the center on .5" bolt welded to the end part of the cabinet support. .5" leveling bolts are just inboard of the wheels for leveling the left side. I'm a little concerned that the .5" welded pivot bolt might not be enough. I'd love some feedback on that.

Here's an isometric drawing to demonstrate the concept. I didn't draw an isometric of the casters because it would a lot of effort that would serve no useful purpose.

View attachment 100881

This is a plan drawing showing the scale and overall details. Elevation view on top and plan view on the bottom. The truck is exploded off the base for clarity. The drawing left of that is the whole end assembly.
On the bottom the assembly view is a elevation view from the side.

The tool cabinet will rest on 1" x 1/8" steel angle spot welded to the rim of the stand.

View attachment 100882

The right and steerable side of the trolly will utilize leveling casters rated at 1100 pounds each. The brackets are .25" steel and gusseted inside.
This is my second area of concern, that the .25" steel will be up to the task of supporting the chest full of iron and lathe. I estimate that the total weight of the stand and lathe will around 1,000 pounds.

Below is a photo of the casters.

View attachment 100883

Franko,

A quick check in the pivot pins says that it is OK to carry the load, based upon the assumption that the total load is 3000 lbs and that it is spread more or less evenly. The 1/8" angle is to thin, and is not so far below the compression limit. I would suggest that you go to 1 x 1/4", and that will be OK. Similar for the thickness of the trolley carriage.

If the total load, lathe and cabinet full of tools is only half of that, then you will be OK.

I built a metal cabinet for my lathe, laser cut, folded and all bolted together, with a suitable sealant on the coolant collector surfaces. It has cupboard either end with drawers on extended guides so they pull right out and a centre cupboard under the swarf collection pan that houses the coolant sump and pump plus its like the dividing head and tool post grinder. Milling column on the lathe.

Duncan

 

[Franko]

Thanks for the input, Duncan. I'm a practical engineer so the math of loads is beyond me. To clarify, you're saying that the .25 caster mounting brackets should be sufficient?

Don't take any of my comments as challenging your advise. This is how I learn. I really appreciate your input.

The box is rated for 3000 pounds but I don't expect the weight of the lathe, box and tools to be much more than 1,200 pounds. The lathe is a bit over 500 pounds, the box about 200 pounds, leaving a pretty generous allowance for tools, chucks and other iron and steel gizmos that will reside in the box.

I intend for the fit on the trolly to be pretty tight to the sides of the box, allowing about a tenth of an inch of slop. It will fit the bottom of the chest like a shoebox lid. The bottom of the box is not flat. There is a lip around the edge. That's why I thought .125 x 1 angle lip would suffice, as all the load will be within about 0.2" of the angle, which will be spot welded every 10 or so inches along the length of the base.

By "spot welding," I mean drilled and TIG welded.

If I use .25 angle, it almost wouldn't need to be angle as the thickness would be sufficient to support the sides of the cabinet. I guess the advantage of using angle is for a little additional stiffening support against outward bowing, though I don't see how that can happen if the fit is tight.

I considered just welding a 3/16 x 3/4 strap around the bottom to make a 3/4" lip, but figured I have a better shot at everything remaining square and straight if I use angle.

Another difficulty is how to weld the end pieces to the front and back pieces. All the welding has to be on the outside as a bead anywhere on the inside will interfere with the fit of the cabinet in the stand. The ends are designed to fit with a T-butt joint. I'm pretty sure my welding skills are good enough to get pretty good penetration if I bevel before welding, but it worries me that they will only be welded on one side of the joint. I suppose if I don't run the support angle lip all the way to the inside corners and leave a gap, that I could put an additional 1" inside corner bead where the torquing forces are the greatest.

My concern for the 1/2" pivot is that there is a lot of leverage on that connection because the way the wheels stick out from the 1/4" x 2" strap. I've considered adding two more studs and nuts through a slot outboard of the pivot to tighten and help hold the 1/4 x 2 strap tight to the ends to resist torquing.

 

[Whyemier]

I have a Grizzly, 'older' Grizzly (15 years old now), 11-27 Lathe. I think it is the same basic machine but doesn't have all the bells and whilstles of the new lathes. I'll keep an eye on what you do here and hope there is something I can use with mine.

Thanks for this post.

 

[Franko]

Thanks for your interest, Whyemier. My current lathe is a Grizzly G-4000. It has been a good lathe for me and has done all I'm up to so far. It is just a tad short and only has two speeds. The big 1.5" spindle bore (and variable speed control) is what I'm most excited about with the PM1127. It isn't a very long lathe, but the big bore makes up a lot of its lack of length between spindles.

 

[Whyemier]

I have had no complaints from my older lathe. Well aside from no reverse on mine until I added such a few months ago with a modification to the banjo. It does all I want it to do.

 

[Quai_Oui]

Thanks for the input, Duncan. I'm a practical engineer so the math of loads is beyond me. To clarify, you're saying that the .25 caster mounting brackets should be sufficient?

Don't take any of my comments as challenging your advise. This is how I learn. I really appreciate your input.

The box is rated for 3000 pounds but I don't expect the weight of the lathe, box and tools to be much more than 1,200 pounds. The lathe is a bit over 500 pounds, the box about 200 pounds, leaving a pretty generous allowance for tools, chucks and other iron and steel gizmos that will reside in the box.

I intend for the fit on the trolly to be pretty tight to the sides of the box, allowing about a tenth of an inch of slop. It will fit the bottom of the chest like a shoebox lid. The bottom of the box is not flat. There is a lip around the edge. That's why I thought .125 x 1 angle lip would suffice, as all the load will be within about 0.2" of the angle, which will be spot welded every 10 or so inches along the length of the base.

By "spot welding," I mean drilled and TIG welded.

If I use .25 angle, it almost wouldn't need to be angle as the thickness would be sufficient to support the sides of the cabinet. I guess the advantage of using angle is for a little additional stiffening support against outward bowing, though I don't see how that can happen if the fit is tight.

I considered just welding a 3/16 x 3/4 strap around the bottom to make a 3/4" lip, but figured I have a better shot at everything remaining square and straight if I use angle.

Another difficulty is how to weld the end pieces to the front and back pieces. All the welding has to be on the outside as a bead anywhere on the inside will interfere with the fit of the cabinet in the stand. The ends are designed to fit with a T-butt joint. I'm pretty sure my welding skills are good enough to get pretty good penetration if I bevel before welding, but it worries me that they will only be welded on one side of the joint. I suppose if I don't run the support angle lip all the way to the inside corners and leave a gap, that I could put an additional 1" inside corner bead where the torquing forces are the greatest.

My concern for the 1/2" pivot is that there is a lot of leverage on that connection because the way the wheels stick out from the 1/4" x 2" strap. I've considered adding two more studs and nuts through a slot outboard of the pivot to tighten and help hold the 1/4 x 2 strap tight to the ends to resist torquing.

Franko,

I only checked the pin loads. Initially for the shear load in the pin alone. Then I thought that I should also check the crushing load of the pin in the angle. I would still recommend that the angle, and if it was me I would use angle for the reasons you have given, should be 1/4" thick. You could do this with a doubler plate. I did not check any of the other strength requirements, but I would have thought them generally to be OK. Be aware that it will not take a lot to double the loading with tooling etc, so some reserve is a good idea.

For you welding, to get a full penetration leave about a 1/16th gap ( these days I'm working in metrics), by tack welding the items with this. do this once you have made the bevel. You should then with the right power (read current) get a full penetration with a small bead on the inside. This is used wherever single side welds are employed. A very good example is pipes. They need to withstand full pressure, have no corrosion nooks, and not disrupt flows. Also used in many other application. Even the first weld on two sided welds, where the bead and some material is gouged out for the second weld. The bead is nothing that will worry the seating of the chest. If necessary add a radius to the bottom corners. That will not detract from it sitting nicely or the load bearing.

Providing the chest load is generally spread over the trolley, then the only load is downwards and that is taken at the rest points (castors), so there could be a tendency for the attachment areas to bend up a little from the bending moment applied at this point. An angle will reduce this, a box section would more or less stop it. But in reality the loads are not large even at 3000 lbs that is only 750 lbs at each point for a uniform load or perhaps 1000 lbs at the head stock end.

Good luck with you project.

Duncan

 

[Franko]

Thanks, Duncan. I appreciate your time and thought on this.

I went to the metal store today and purchased most of the steel.
I was lucky to find a drop of 6x6 3/8" angle for the caster bracket. I doubt that it will even need to be gusseted.
I also decided to increase the thickness of the stationary wheel caster bar from 2" x 1/4" to 3/8" thickness.

If I get a penetration bead inside the corner welds, it most probably wouldn't decrease the strength if I grind the weld protrusion square inside. It would also be possible to hammer some bevel on the cabinet base.