Stand Design for benchtop Mill- looking for feedback

[StevSmar]

I purchased the PM-835TV Mill below, but didn't buy the matching stand since I thought a custom stand would suit me better.


This is what I'm thinking of for my design constraints (in order of priority):
1) Must allow full Z travel, ideally when a future ceiling is installed (about 50mm required for a T-bar ceiling, though I could just use 5/8" drywall in the vicinity of the Mill).
2) The height of the stand should be maximized, but not so high that controls are uncomfortable to reach.
3) Width about the same as the travel of the table.
4) Depth so that I don't hit myself on the Y handle.

Optional:
O1) It would be nice if the stand is low enough so that it can be moved under the "Red" HVAC duct and "Green" wooden beam with the mill installed on the stand (see images below).

This is the general concept, it's what I call a "massing model", it shows the overall dimensions but not any of the detail:
The purpose of the front "notches" is so that I can reach around the Mill easier, to operate the Z-axis power feed.

Here you can see the "Red" HVAC duct and the "Green" beam:


Front view with the table moved all the way to the left, the power feed just overhangs the end of the table:


In the left view, the head raised to the full height leaves about 50mm from the underside of the beams:


In the right view, with the head lowered down the top of the Mill will fit under the "Green" beam:

(The Human Model is about 20mm shorter than I am, so that's why it's not sitting quite on the floor slab)
(I made the model for the Mill in Fusion 360. It doesn't include all details, though since I like modelling I made it more complicated than it needs to be...)
(The PM-835TV weighs about 750lbs (340kg), so I think the stand will ultimately end up being quite substantial. About the only thing that is potentially set in stone is that I've got some 2"x2"x1/4" thick tubing for the cross members)

 

[Susquatch]

Wow...... I got nothing.

 

[StevSmar]

I was getting pressured to go for a walk, so I didn’t add that at this stage, I’m looking for feedback like “it’s too high, you’ll get a sore back” etc…

Once the overall dimensions are firmed up, then I’ll flesh out the other details of how I’m thinking of building the thing.

 

[garageguy]

only thing I would change is move the front edge of the stand back away from you so it doesn't protrude any farther forward than the front edge of the mill. Freedom to move and get close to the mill is a huge advantage at times.

 

[phaxtris]

Is there a reason you have it so wide on the x? Are you planning on putting drawers in there ?

 

[LenVW]

That is a nice mill.
My recommendation is to build your base out of some flanged I-Beam.
That will allow you to create a bolted frame that is custom to your space.
You can also use the flanges on the beams to accommodate braces and x-braces.
Create a boxed in enclosure and put a few patio stones in the base when you get it positioned.
Ballast will help to damped machining vibration and reduce resonance.
Lots of fabricators like to weld frames, but, if you want to change it down the road you will be working with a torch and dealing with heat warp and expansion.

 

[StevSmar]

only thing I would change is move the front edge of the stand back

That’s a good suggestion, plus I noticed on the side view that the Y-axis handle doesn’t have much clearance. So the tops front edge really needs to be behind the Y-axis handle.

 

[StevSmar]

Is there a reason you have it so wide on the x? Are you planning on putting drawers in there ?

Yes, that was one of the reasons. Plus I thought it would be a pain if I needed to move things from an adjacent bench if I traversed the table to it’s full extent- so I thought I may as well make “side” cabinets that have drawers.

 

[StevSmar]

My recommendation is to build your base out of some flanged I-Beam.

I thought about that and I’m hoping that the square tubing for cross bracing will have a similar or better stiffness, and allow me to squeeze another drawer in.

That’s an interesting idea about having it so ballast can be added!

Lots of fabricators like to weld frames, but, if you want to change it down the road…

I forgot to mention in my initial post that the bench also has to be able to be disassembled to get it out of the basement. It would sure be miserable to have to get out a cutting torch to do that…

 

[LenVW]

I have reconfigured a lot of production lines for industrial plants.
Welded frames are rigid and sturdy, but it takes a lot of work to change arrangements after they are welded. I have bolted together many smaller weldments for huge process machinery skids and have made major alterations to industrial equipment (250hp extruders & 20ton profile dies) after years of in-plant use.
If you need to move equipment it is nice to disassemble the equipment into smaller sections that are easier to handle and modify.
Plan for future changes and you will make life easier.

 

[PeterT]

Agree with suggestion to lop off the front bay window area. Serves no purpose, no room for your hand under the cross slide handle & toe interference near floor. So you will naturally be further back from work & kinking your back for proper looksee. The side wings are nice if they accommodate tools & accessories, nice & close. But the machine will vibrate & so will everything in it. My RF45 stand was the stock tin can maybe 3" peripherally bigger than the mill base. So that footprint is stable enough. Another option is make it beefy but just big enough for the mill & apply your skills to separate shelf unit. That way you can engineer the shelves & contents logically. For example pulling a heavy rotary table or vise from way down low elevation is not fun & actually more pita when associated with your mill with handles & tables sticking out. Also contemplate DRO, it occupies space which might conflict with your design so look at some comparable setups. I like rubberized jack feet for levelling & vibration dampening

 

[PeterT]

@StevSmar what cad modelling software did you use?

 

[phaxtris]

here are my thoughts

i would stick with the hss idea, i beam is not very stiff for its weight without adding a bunch of stiffeners and bracing.

2x2x.250 is pretty serious overkill, so unless its free and you really want to use it up i would be looking for something much lighter, 100 wall would be more than strong enough for the whole stand and less than half the weight. A welded stand is going to be stiffer, easier to fab up, and require less bracing and if for some reason you absolutely had to cut it up a zip cut makes fast work of tubing.

i agree with @PeterT, make your mill stand just big enough for the mill with a few shelves or drawers under, and use the rest of your time or money to buy or build separate drawer units that can roll under each side if thats what you want

small shops are always changing, at first you think thats a great spot for the machine, then you buy another machine or find out that wasn't the best spot, or you just don't like it there.....its easier and more flexible to have a smaller stand with moveable chest of drawers that can be re-arranged as the need arises than a great big table thats set in stone so to speak

 

[whydontu]

Unistrut.

Not cheap, but very strong, lots of components, easy to modify.

Unistrut is the number one choice for metal framing needs

Unistrut offers the most comprehensive line of channels and fittings, along with a complete line of hangers, pipe clamps, concrete inserts, and accessories

www.unistrut.us

 

[StevSmar]

Plan for future changes and you will make life easier.

I’m planning on making the sides of the stand out of wood, so that if I change my mind on sizing it’s easier to change. Perhaps I’ll eventually make the sides out of metal in the future, though if the wood is working well I’ll probably just leave well enough alone.

Regardless, the sides will be bolted to the cross members.

 

[StevSmar]

Agree with suggestion to lop off the front bay window area. Serves no purpose, no room for your hand under the cross slide handle & toe interference near floor. So you will naturally be further back from work & kinking your back for proper looksee.

Yes, I should have shown the toe kick area before I posted the images above. I’ll show that in the next iteration.

The side wings are nice if they accommodate tools & accessories, nice & close. But the machine will vibrate & so will everything in it.

Ooooh, I hadn’t thought of that. That could be super annoying. I’m guessing the stand will be around 500lbs at the rate I’m going…

My RF45 stand was the stock tin can maybe 3" peripherally bigger than the mill base. So that footprint is stable enough. Another option is make it beefy but just big enough for the mill & apply your skills to separate shelf unit.

That’s a good idea. I think I like the idea of one wide stand though because I’m worried about stability. The stock stand was heavy, but looked tippy to me: PM-833T stand Plus it didn’t look like it was a very efficient use of space, something that’s precious in my shop.

Also contemplate DRO, it occupies space which might conflict with your design so look at some comparable setups.

I have a DRO. The installations I’ve looked at don’t appear to require coordination with the stand so I didn’t bother adding them to the model.

I like rubberized jack feet for levelling & vibration dampening

Me too. I have four Levelling Pads but may need some more if the stand gets too wide.

 

[StevSmar]

@StevSmar what cad modelling software did you use?

I’m using Fusion 360, the free version with some functionality limitations

 

[StevSmar]

2x2x.250 is pretty serious overkill, so unless its free and you really want to use it up i would be looking for something much lighter.

It certainly does feel like overkill when I pick it up for sure!!! It’s what I had available so that’s what I’ll use.

i agree with @PeterT, make your mill stand just big enough for the mill with a few shelves or drawers under, and use the rest of your time or money to buy or build separate drawer units that can roll under each side if thats what you want.

I better seriously consider this option. If the mill is stable with a smaller stand then the “side wings“ could be like mobile benches That live next to the mill but which can be moved elsewhere when necessary.

…small shops are always changing…its easier and more flexible to have a smaller stand with moveable chest of drawers that can be re-arranged as the need arises than a great big table thats set in stone so to speak

That does make sense!

 

[StevSmar]

Unistrut... Not cheap, but very strong, lots of components, easy to modify.

I had considered Unistrut, but the 2x2 tubing was available and I thought it would be stiffer.

 

[whydontu]

I had considered Unistrut, but the 2x2 tubing was available and I thought it would be stiffer.

2x2x1/4 square tubing is probably 10x stiffer than 1-5/8 10ga strut.