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View Full Version : How do I make my lathe stand more rigid



AlexK
03-16-2010, 03:11 AM
My Chinese lathe's stand is essentially two cabinets connected together by nothing more than a thin piece of sheet metal.
I want to make it more rigid with some heavy rectangular steel tubes I already have.

What is the best way to approach this project? Do I need a welder or can get away with bolted connections?



http://www.machinetoolonline.com/sitebuilder/images/PM1236_005-402x329.jpg

The Artful Bodger
03-16-2010, 04:08 AM
Hi Alex, your lathe looks the same as mine including the stands.

I did not feel rigidity of the stand compromised the lathe at all and my machinists' level confirms the lathe is not twisted. What did concern me though was the possibility of something untoward causing the lathe to topple forwards so, not wanting to drill the floor, I took 4 pieces of timber 4x4 about 3 feet long and bolted the cabinets down to these, the end of the timbers extend out from the front of the cabinets about 12 inches. It now feels much more secure and incidently raised the lathe to a more comfortable height for me.

John

Richard-TX
03-16-2010, 04:12 AM
If you want to make the cabinets more rigid, add diagonal bracing. Personally if the stand is shoddy, then I would make some new ones.

Here is a picture of my stand prior to trimming to show how it was constructed. It doesn't move. It isn't the best and certainly not the worst. I do like the drawer space a LOT. It was made from rectangular tubing then welded together. The sides, top, and back were welded to the tubing. All of the steel was drops from the local steel yard.

http://rich.homeunix.com:443/metal-lathe/pics/HPIM3282-r.jpg

RB211
03-16-2010, 04:50 AM
Fill it with concrete

macona
03-16-2010, 05:22 AM
Fill it with concrete

Or make one out of concrete. There are instructions over on PM from WWII on making a base out of concrete for precision work. They are in the South Bend section.

MuellerNick
03-16-2010, 05:27 AM
My lathe is similar, and the base is worse than what sits on top of it.
The doors are useless, nothing fits into them.

1.) Tear out the 0,7mm sheet metal that is supposed to act like drawers.
2.) Check that the top plate and the one or two stiffening ribs that should ... well ... stiffen the top plate are actually weldet together. Not tacked with 3 spots, but welded. Mine were not. There was a 2mm gap. Useless! Weld it!
3.) Have a look at the base, where the holes for the bolts are. A few tacks only! Weld it! Whatever rect tube you find, you can weld into the columns.
4.) Screw the lathe down to the floor. That makes an incredible difference. Surface, vibrations, depth of cut! And you can even twist and bend the bed in almost any shape. That takes a machinists level and a lot of patience and 6 bolts into the concrete floor.

Don't weld the connection between the feet, it doesn't make a difference. That paper ... er ... sheet metal is only facade.

Bob Farr
03-16-2010, 05:44 AM
Consider building a cross braced box section to install between the cabinet uprights, then maybe add a sheet across the full length of the back to tie it all together well. Something similar to this.

In my case I was trying to use some cast end columns from an old Walker Turner gang drill, and added a steel surface to make a bench for my Atlas/C'man 12x42 lathe. It was flimsy, easily rocking laterally and twisting the surface:

http://i58.photobucket.com/albums/g272/frankenglide/Refinish2.jpg

I built a box of 3/4" plywood. The internal cross braces sit in groves (dato's?) in both sides, plus have additional bracing fillets added:

http://i58.photobucket.com/albums/g272/frankenglide/Table1-2.jpg

With both sides of the box glued and screwed to the inner cross braces it is very tortionally stiff. It is then squeezed between the two cast end columns with long all-thread top and bottom:

http://i58.photobucket.com/albums/g272/frankenglide/Table2-2.jpg

It sucks loosing the possible storage space between the columns, but it worked great to strengthen the base against rocking and twisting in all directions:

http://i58.photobucket.com/albums/g272/frankenglide/Table3-2.jpg

A similar box between your cabinets, with a long back section that extends across the back of your end cabinets, would probably work very well for you. You would retain the storage space of your cabinets, you could use the natural "V" of the internal bracing as a replacement chip catcher, and the front face of the new box section can still be used as a place to hang commonly used tools on pegs.

Good luck,

Bob

MuellerNick
03-16-2010, 06:00 AM
With both sides of the box glued and screwed to the inner cross braces it is very tortionally stiff.

From a carpenter's POV, it is stiff.
From a structural POV, it is soft.

Here's an experiment:
Clamp a dial indicator stand onto the chuck. Adjust it to stick out as much as possible along the spindle's axis. Put a dead center into the tailstock. Put a dial indicator onto the stand and let its tip touch the center.
Now lean onto your lathe. You will be ****shocked****

There are only two solutions:
1) Screw the lathe to the floor.
2) Decouple the lathe from the stand. Boley's do only have 3 fixture points where the bed is screwed to the stand. No matter how the stand flexes, the lathe won't move.

And wood moves with moisture. One day adjusted, the next day out of alignment.


Nick

Bob Farr
03-16-2010, 10:16 AM
All true Nick, but I can only tart-up a sow's ear so far :D

I'd actually like to replace the steel surface with a thick maple one. I think that would add another stiff plane to the "box" and dampen vibrations down some too. The lathe bed legs sit on three points on the table surface and the wood box is well sealed against moisture penetration with several layers of paint. It's in my dry basement, and the temps don't vary much there either. Random movements are minimal, and it works pretty well for my use.

MuellerNick
03-16-2010, 10:27 AM
The lathe bed legs sit on three points on the table surface ...

Then that's a different story.
In this case, the stand can't add much to the lathe's precision.Only some mass, a bit of dampening, but no stiffening at all.
At least, lotsa storage. :-)


Nick

AlexK
03-28-2010, 06:37 PM
My 12x36 lathe is attached to the stand by 8 bolts.
For rigidity I can bolt the lathe first to a thick metal plate and then this assembly can sit on not so rigid original base even on three points. The minimum plate size must be 8"x 50" so both lathe feet can fit on it.
I am thinking to get 1" thick plate 16"x50"
Not sure how much it'll cost yet. I don't want to go over $200.
What do you think? Will it be sufficient, overkill?
BTW Concrete floor in my garage is only 1" thick so bolting to the floor won't do much.

The Artful Bodger
03-28-2010, 07:37 PM
My lathe is lower than I like when standing on its cabinets and them on the floor so presently they at standing on wooden 'feet'.

I do not see any reason why one could not pour a 4" or so slab of concrete (length and width of the lathe) on top on an existing floor and even seperated by a sheet of plastic if desired. This would give considerable mass and still not mean drilling holes in an existing or rented floor while raising the lathe to a more comfortable working height.

TGTool
03-28-2010, 10:30 PM
I'd actually like to replace the steel surface with a thick maple one. I think that would add another stiff plane to the "box" and dampen vibrations down some too. The lathe bed legs sit on three points on the table surface and the wood box is well sealed against moisture penetration with several layers of paint. It's in my dry basement, and the temps don't vary much there either. Random movements are minimal, and it works pretty well for my use.

This isn't perfect but it helped. I went down to the Habitat Re-Store that has recycled building items and bought a couple thick solid core doors. Cut to size, bolted together and banded around the edge with 1 x it makes about a 150 lb 3 1/2" base for the lathe. The stand doesn't do much except give some storage space and bring the machine up to work height.

... and I've been struggling to resist the urge to suggest taping a packet of Viagra underneath.

Black_Moons
03-28-2010, 11:00 PM
I recommend remaking the stand entirely, those little cabinates suck, and whats all that room under the middle of lathe for thats unusable? your feet? do you really sit at a stool?

bolt on some drawer slides and make pull out heavy duty drawers for chucks and tooling! then make a giant frame outta giant peices of angle iron or even square tubing.

One kinda scary thing about a flexable frame is when the vibration sets in it can start resonating with the frame and bam, 10x the vibration at some rpm then others. Of course, you can just note down that RPM and never use it again for offset turning, but finding it can be scary.

But consider the 500lbs of tooling you will be able to add as a great 'vibration dampener', Especialy as its likey all loose with its own independant resonsances on dampening non slip pads.
How much tooling can you fit in those puny boxes? 100lb? maybe 200lb? blah! And you ever try and pull an 8" chuck or 10" faceplate outta one? not easy!

doctor demo
03-28-2010, 11:08 PM
I am thinking to get 1" thick plate 16"x50"
Not sure how much it'll cost yet. I don't want to go over $200.
What do you think? Will it be sufficient, overkill?
BTW Concrete floor in my garage is only 1" thick so bolting to the floor won't do much.

I'm not a structural engineer but I think it is both overkill and insufficient at the same time. A 16''X 50'' plate is going to be flexy even at 1'' thick and it is going to add a lot of top heavy weight to the foot print. I would work on making the cabinet/stand more rigid with some strategic bracing instead.

Steve

Evan
03-28-2010, 11:53 PM
This is what I did. It is entirely possible to build a wooden bench that is more rigid than a steel bench. The top is a frame of 2x4" lumber that is cross braced and then has a 3/4" 5 ply panel glued and screwed to both sides. This produces a box section that is extremely resistant to twisting or bending. The top is bolted to a lower cabinet that is constructed the same way. The lathe is bolted and shimmed to a 10" section of channel iron. The channel is lightly fastened to the bench top.

Using a master precision level the lathe is aligned to a few arc seconds and it stays that way, even if you jack up the bench at one corner. The bench is strong enough to hold quite a few tonnes load.

http://ixian.ca/pics6/lathe_mount.jpg

.RC.
03-29-2010, 01:59 AM
Rub the stand with Viagra??

oldtiffie
03-29-2010, 02:32 AM
My thoughts too Ringer.

But I thought that with all the excitement and the necessary rush of blood from the head they'd have a dizzy spell and fall off the end of it and have a major flaccidity crisis.

http://www.google.com.au/#hl=en&source=hp&q=penile+flaccidity&btnG=Google+Search&meta=&aq=f&aqi=&aql=&oq=penile+flaccidity&gs_rfai=&fp=18a51b3ed23f0245

philbur
03-29-2010, 03:13 AM
Only trouble is you now keep tripping over the supports sticking out 12" in front of the lathe and fall flat on your face.:D

Phil:)



I took 4 pieces of timber 4x4 about 3 feet long and bolted the cabinets down to these, the end of the timbers extend out from the front of the cabinets about 12 inches. It now feels much more secure and incidently raised the lathe to a more comfortable height for me.

John

The Artful Bodger
03-29-2010, 03:47 AM
Only trouble is you now keep tripping over the supports sticking out 12" in front of the lathe and fall flat on your face.:D

Phil:)

Nope! Not as much as stubbed my toe (as yet).:D

RussZHC
03-29-2010, 11:30 AM
Just finished reading other posts regarding using concrete for "cabinets" or bases for machinery.
In an effort to think off the beaten path, how about using some of those pre-cast concrete planters, or for that matter municipal garbage containers?

The smallest concrete ones locally must be very close to the needed height, bolt a couple together with really beefy angle iron...
Now, at least in the northern hemisphere, would be the perfect time as home improvement box stores will be clearing last years left-overs. And they are already made to add more weight, sand/gravel/rock, if needed.

sidneyt
03-29-2010, 11:52 AM
Bolting the lathe down will definitely stiffen it up. I cast two concrete pads with 1/2" studs sticking up on the headstock end pad. It had the added benefit of raising the height of the lathe to a more optimum level.

http://i218.photobucket.com/albums/cc123/philt214/Lathe/8c24.jpg

http://i218.photobucket.com/albums/cc123/philt214/Lathe/65bf.jpg

http://i218.photobucket.com/albums/cc123/philt214/Lathe/44ea.jpg

AlexK
03-29-2010, 12:56 PM
Guys, thank you for all your input.
Correct me if I am wrong.
You get less flex/more stiffness in the lathe when you attach the lathe directly to a more massive and rigid part.
When you place anything that is not so rigid between the lathe and a rigid/massive part(like cement floor) you get more flex.
Let's make a thought experiment.
Imagine a lathe on two standard sheet metal cabinets with cabinets bolted to the floor. Now if we increase the height of the cabinets we will increase the flex too.

That makes me think that to get the the most bang for a buck we should attach a lathe directly to a "rigid body" like massive metal or granite plate.

Beefing up the stand would also decrease flex but not be as effective as attaching the rigid plate directly to the lathe.

MuellerNick
03-29-2010, 01:17 PM
Directly bolt it to the floor, without any stands. Dig a hole in front of it. Also makes a good ditch to get under your car.

Innovations, innovations!

Nick

Evan
03-29-2010, 01:19 PM
The best bet is to bolt the lathe to a piece of channel iron like I did. It creates another structural member that is part of the lathe and makes it a truss which is many times more rigid than the original bed.

I could place it on a straw bale and it wouldn't twist.

The Artful Bodger
03-29-2010, 01:24 PM
Oh heck! Learn to squat like a fakir and bolt your lathe directly to the floor slab!:D

Too_Many_Tools
03-29-2010, 02:08 PM
If you want to make the cabinets more rigid, add diagonal bracing. Personally if the stand is shoddy, then I would make some new ones.

Here is a picture of my stand prior to trimming to show how it was constructed. It doesn't move. It isn't the best and certainly not the worst. I do like the drawer space a LOT. It was made from rectangular tubing then welded together. The sides, top, and back were welded to the tubing. All of the steel was drops from the local steel yard.

http://rich.homeunix.com:443/metal-lathe/pics/HPIM3282-r.jpg

Love the storage of the cabinet.

TMT

Mcgyver
03-29-2010, 03:50 PM
Directly bolt it to the floor, without any stands. Dig a hole in front of it. Also makes a good ditch to get under your car.


on lie in front of it on the deck to operate :D

....ages ago someone on cnc zone advocated that, still makes me chuckle

The Artful Bodger
03-29-2010, 04:03 PM
Directly bolt it to the floor, without any stands. Dig a hole in front of it. Also makes a good ditch to get under your car.

Innovations, innovations!

Nick


Doh! Why didnt some one tell me that months ago? :eek: I already have an inspection pit in the garage which I almost never use and it would have kept all the chips and stray coolant in one place too, oh, domestic bliss!:D

Too_Many_Tools
03-29-2010, 04:17 PM
Along with being just more rigid, I would like to see how one gets more storage and more portability while retaining the rigidiness.

That is the tough but proper solution.

TMT

Black_Moons
03-29-2010, 04:31 PM
oh I final figured out the real solution.
Surface plate.
http://www.dmm.ca/images/personnel/klaus_greve_surface_plate.jpg
Something like about that size should do it!

Now just hope your lathe mounting points where ground flat to the bed or you'll have to shim it still :(
Id recommend sticking the entire lathe onto a giant surface grinder, just to be sure....
<end lathe precision nazi mode>

BobWarfield
03-29-2010, 06:06 PM
I welded up a good solid stand for my mill:

http://www.cnccookbook.com/img/Welding/MillTable/P6053451.JPG

You can definitely tell the difference.

Cheers,

BW

gearedloco
03-29-2010, 06:56 PM
All true Nick, but I can only tart-up a sow's ear so far :D

I'd actually like to replace the steel surface with a thick maple one. I think that would add another stiff plane to the "box" and dampen vibrations down some too. The lathe bed legs sit on three points on the table surface and the wood box is well sealed against moisture penetration with several layers of paint. It's in my dry basement, and the temps don't vary much there either. Random movements are minimal, and it works pretty well for my use.

I think it is the case that paint is not a good barrier to water vapor. Ordinary shellac is much superior. FWIW.

-bill

Too_Many_Tools
03-29-2010, 11:30 PM
[QUOTE=AlexK]My Chinese lathe's stand is essentially two cabinets connected together by nothing more than a thin piece of sheet metal.
I want to make it more rigid with some heavy rectangular steel tubes I already have.

What is the best way to approach this project? Do I need a welder or can get away with bolted connections?

QUOTE]

Whatever you build, make sure you can move it later.

I have seen several beautiful lathe cabinets trashed because they were too heavy or too big to move.

One was built inside a shop...and when it came time to move it would not fit through the door.

TMT

loose nut
03-31-2010, 11:02 PM
The best material for a stand is cast iron, the next is Mass.

I made mine from 1/4" Stainless plate (don't ask) with a 3/4" thick top for mounting bolts and weigh 250 LBS. each, both base's can be loaded internally with another 200 pounds of weight if necessary. Their the black bits with the yellow mountings, sorry poor picture.


http://i135.photobucket.com/albums/q153/loosenut_bucket/DSC00098.jpg

Black_Moons
04-01-2010, 01:44 AM
You painted 1/4" stainless plate? -_-;

dian
04-01-2010, 03:42 AM
Or make one out of concrete. There are instructions over on PM from WWII on making a base out of concrete for precision work. They are in the South Bend section.

hi, what is "WWII"? thanks.

Mcgyver
04-01-2010, 07:57 AM
hi, what is "WWII"? thanks.

World War II I'd assume

that site has gone so mental with forum creep, its hard to bother with it beyond the general metalworking section....I couldn't see a southbend section

Too_Many_Tools
04-01-2010, 09:24 AM
I welded up a good solid stand for my mill:

http://www.cnccookbook.com/img/Welding/MillTable/P6053451.JPG

You can definitely tell the difference.

Cheers,

BW

Very nice stand.

Does it fit through a doorway?

TMT

loose nut
04-02-2010, 02:45 PM
You painted 1/4" stainless plate? -_-;

Of course, just 'cus it's in the shop doesn't mean it shouldn't look purdy, It had a matte finish not a shiny one. I had originally planned to seal weld the seams so that they could be filled with water (the reason for stainless) for extra ballast, easy to drain for moving, but I figured sand or gravel would work well enough so there are a few spots that didn't get completely welded.