So my 3/4" plywood table is starting to develop some fairly serious ruts where the non-rail side Y bearings ride on the (soft) table surface. Picture doesn’t show it well, but they are already >1mm deep after only a few movements of the machine.
My plan has been to use a strip of some harder material on the table surface for the bearings to ride on instead of the softer plywood. The only question is what material to use.
I have a partial sheet of ~2mm hardboard that seems hard enough. The drawbacks are:
a) it is thick enough that I will probably have to shim up the rail side as well to maintain the same Z height travel on both sides
b) it will have to be installed in two pieces, meaning the rollers will run over a seam
The other option I have been considering is 1.5" edge banding (either white melamine or maple). It comes in a 25’ roll, so it will install in a single strip with no seams. The drawbacks are:
a) Its only 0.5mm thick, so durability is a huge question mark
b) It is applied using an iron to melt the glue adhesive, and there are lots of reviews where the adhesive is rated as poor/patchy/inconsistent. Plus removal might be messy.
Does anyone here have any other suggestions as to a material that might be suitable. Ideally it would be:
Fairly thin so as not to raise the wheels significantly, but thick enough to be durable (~1mm)
Available in a 10’ length or longer so as not to require seams
Minimum 1.5" wide
Reasonably inexpensive
Reasonably easy to attach to plywood, and reasonably easy to remove/replace in the future.
My full sheet LR3 has been riding on MDF since I originally built it and its been good. There is a seam in the middle and it has never caused me any issues. If you have enough hard board to run down the bearing side and under the Y rail clips that sounds like a winner to me. That way you are lifting the same amount on both sides.
I’m assuming it’s not really wearing but compressing so I’m not sure it would get much worse. I wonder if you can just patch it with wood putty or something and sand it smooth.
Autobody filler is hard and durable. I might run a router down the side to dig a groove to fill with it, (I bet most of us have a serviceable trim router, ) then work it smooth before it fully cures. Somewhere between 3 and 6mm deep (1/8"-1/4") is in a good range for bondo, and maybe 10-12mm wider than the bearing wheel to distribute load. A small can of body filler would be enough, and not too spendy.
Not really. Only a day or two of use, but the gantry is quite heavy (1" 0.120 stainless tubes x2, 1545mm long), and the plywood is fairly soft (can leave a deep mark with my fingernail)
I was planning to do this before installing whatever I put on top of it, but…
…so I’m not sure that it would be suitable for the rollers to ride on
This may be the answer, unless anyone has any other ideas?
You’ve obviously never tried to sand down body filler left over a weekend when your SO decided that you had to come in from the garage before you were done.
It’s pretty soft for a few hours, up to 90 minutes, and you can cut it with a knife. Easily sandable for a few more hours, giving ypu time to get the contours right, then less so. Glazing and spot putty for a final smoothing wouldn’t be necessary if body filler were that soft.
It will be harder than acrylic, most definitely harder than the wood. It should be harder than epoxy resin, too. Fibreglass might be stronger, but for a smooth trxture, you’d generally use body filler anyway.
I used hardboard for mine, and to keep it level I put it under both the rail clips and on the roller side. Since mine is ~10ft long and all the hadrboard panels I had around were 8’, nine has a seam as well. With a tiny bit of care (basically making sure both ends were square and clean) the seam is visible but you can barely feel it with a finger and the bearings don’t notice it at all.
) then work it smooth before it fully cures. Somewhere between 3 and 6mm deep (1/8"-1/4") is in a good range for bondo, and maybe 10-12mm wider than the bearing wheel to distribute load. A small can of body filler would be enough, and not too spendy.
