MDF safe/ adequate for a steady rest frame?

[Brian Kopp]

Hi folks,
I recently built a steady rest frame from two layers of 3/4” MDF, laminated together, so 1 1/2” thick and 2 1/2” wide. It’s feels fairly stout.

I was subsequently warned MDF isn’t structurally strong enough for this application and the frame could catastrophically fail while turning a heavy project, and to start over with plywood instead.

What’s the consensus? Does a steady rest frame typically undergo enough stress to worry about failure of this laminated MDF steady rest frame during use?

If so, would laminating and cross bolting 1/4” plywood on both sides of the frame be sufficient to prevent possible failure?

Frankly I’m relatively new to this, but this one turned out so well I’m reluctant to start over from scratch, but I will if it’s possibly an issue.

 

[Brian Kopp]

 

[Brian Gustin]

well with it being a full circle, I would think it would be just fine as long as it doesn't get lateral stress (I.E. towards headstock or tailstock) , but I wouldn't want MDF for an "open circle" steady rest (the kind that you can put in while leaving your project between centers) but that is just my opinion , I have no experience with steady rests (though I plan to build one eventually) and I am by no means an engineer.

 

[hockenbery]

You can add a ring of plywood to one or both faces.

I would be most worried about the horizontal MDF pieces. If they are just glued to the upright they will like break off just moving it around. Angle braces bolted through the MDF or some other method to strengthen it would be good.

 

[Brian Kopp]

This is how I plan to mount the wheels, on T track.

 

[Brian Kopp]

You can add a ring of plywood to one or both faces.

I would be most worried about the horizontal MDF pieces. If they are just glues to the upright they will like break off just moving it around. Angle braces bolted through the MDF or some other method to strengthen it would be good.

I’ll probably do something like this above and below the horizontal pieces:

 

[Brian Kopp]

Just curious - Can anyone point to any failures of wood lathe steady rests documented anywhere online?

I’d like to see what failed on them.

 

[Tom Gall]

I think the biggest problem is the MDF clamping block (under the lathe bed). It could delaminate like cardboard. I also don't see a method for clamping/locking it to the lathe bed. A catch (or even extra pressure on the piece while cutting) could cause the whole structure to shift and break the sloppy "clamping" block. I've never used a steady rest so maybe I'm over thinking this.

 

[Brian Kopp]

I think the biggest problem is the MDF clamping block (under the lathe bed). It could delaminate like cardboard. I also don't see a method for clamping/locking it to the lathe bed. A catch (or even extra pressure on the piece while cutting) could cause the whole structure to shift and break the sloppy "clamping" block. I've never used a steady rest so maybe I'm over thinking this.

I will be mounting a cam lock mechanism to make it tight against the bed. I picked up some T track to mount the wheels on Saturday and I just picked up some 1/2” oak plywood to reinforce it, as well as a heavy piece of perforated angle steel to make 8 brackets to strengthen both sides and top and bottoms where the vertical rest frame meets the horizontal components.

I’m going to do this much to reinforce it, then not worry about it further.

I have yet to find evidence of any wood lathe steady rest failures online, and I’m not the first person to build one from MDF.

 

[Tim Mehling]

Your design is good, but as stated above your clamping block might not be secure enough. You might consider changing it ou to 3/4” laminated Maple plywood. Mine is made from all plywood and is much the same design. Has worked well to date.

 

[Roger Wiegand]

I think that if you're putting enough stress on a steady rest to break it you have a different problem than the MDF not being strong enough. The point, I think, of a steady rest is just to dampen harmonic vibrations that can develop in a long spindle, not to support the work in any significant way. I'd be shocked if you could put enough stress on it to break it.

 

[Tim Mehling]

I think that if you're putting enough stress on a steady rest to break it you have a different problem than the MDF not being strong enough. The point, I think, of a steady rest is just to dampen harmonic vibrations that can develop in a long spindle, not to support the work in any significant way. I'd be shocked if you could put enough stress on it to break it.

Good points.

 

[Brian Kopp]

I think that if you're putting enough stress on a steady rest to break it you have a different problem than the MDF not being strong enough. The point, I think, of a steady rest is just to dampen harmonic vibrations that can develop in a long spindle, not to support the work in any significant way. I'd be shocked if you could put enough stress on it to break it.

Thank you!

 

[Brian Kopp]

View: https://youtube.com/shorts/PkuMVIQLKfY?feature=share

 

[Brian Kopp]

I reinforced the MDF with 1/2” oak plywood on one side and perforated angle steel where the vertical frame meets the horizontal, bolted through on all sides.

I haven’t added a way to tighten it down yet. In this video I simply slid the end of a flathead screwdriver under one of the legs a bit and that was enough to make it rock solid steady. I’m thinking about some kind of diy cam that will do the same thing.