Alain Lambert wrote:I don't think a shaft 12 mm or 1/2in is strong enough. Use 3/4 in or 19-20 mm. If your shaft flex during sanding, you will not get equal thickness on your board.
Stuart Mansell wrote:Hello everyone, this is my first post. I'm a novice guitar builder with only one under my belt, built on the EIGM course run by Stephen Hill in Spain. I'm v slowly building No.2 but spend most of my time in the shop making jigs and tools and what have you.
My current project is a home made thickness sander. I found loads of designs and pictures online but one spoke to me so I've been recreating that one. The maker thanks the MIMF on his site which is how I found this place.
Here goes....This is the problem.
I have cut 25ish 18mm ply wood discs which will be stuck together onto a 12mm steel shaft to create the drum.
So each disc needs to have a 12mm hole cut in the middle so it can fit onto the shaft.
I don't have a pillar drill so I created a jig and used a 12mm router bit.
I ran a couple of tests last night. I routed out 2 of the discs and put them onto the steel shaft however they fit a little too loosely. It seems there is about 0.1mm/0.2mm discrepancy between hole and shaft.
Before doing this I asked the chap who made it, how his wooden drum was fixed to the steel shaft. He said all the discs were glued to each other on the shaft and its fixed in place by that alone. (I'm reluctant to keep asking him more questions.he's been very kind already.)
I imagine for his method to be effective, one would have to have a pretty tight fit in the first place...something I don't have.
So either the shaft is a little thin or the router bit is cutting wide. Annoying. Both were bought with 12mm being the spec.
The options I have come up with so far are...
1. Try and match the holes i cut to the shaft by buying an 11.8/11.9mm drill bit (don't think router bits come in that size) and drilling the holes out. (I don't have a pillar drill so Id also have to make some kind of jig to make sure all holes are consistent.
2. Try and make the shaft match the hole. Ie adding some kind of layer of something. Tape? Glue? Etc although this seems to just be another element that could cause the drum to slip.
3. Go with what I have and hope the glue fills the tiny gap and holds it all in place.
Is that something tight bond does?
4. Find a method of securing the drum to the steel shaft at either end.
If anyone has any insight or ideas on any of this I love to hear them. I'm very eager to avoid any major issues down the line.
Thanks for reading
Stu
Brian Evans wrote:When you fit the drive to it, I would just fasten it to the wooden discs as well as the metal shaft, and that should solve any drive transfer issues.
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