Back at the end of January, Nelson started this discussion on modifications for an oscillating spindle sander.
Several of us batted around the idea of making a template guide for the OSS (which was Nelson's original question). And I wondered if anyone would give it a shot.
I haven't noticed if anyone did it or not but I've had an idea brewing in my head how to do it for some time now and I finally got the chance to do it.
I made it out of MDF, although I would really like to make it out of aluminum as I think the guide ring would most certainly be stiffer. This really did work though so I'll walk through the steps I did to make it. Maybe someone else will make it out of aluminum.
I have a ridgid OSS but I'm pretty sure something like this could work for what ever model you have.
I didn't take pictures of the entire process (I'm pretty bad that way) as once I got working, I just kept on going and forgot about the camera. So, I'll give written details with some pictures at the end.
OK, I started out with a small piece of 1/4" MDF. 10"x14". I roughly layed out where I wanted the hole to be, based on the deck of my OSS. I drilled a 1/4" hole there.
Then, I put the largest diameter sanding drum on the OSS (which is a 2") and I cranked it down as much as I dare (I wanted the rubber drum to expand as much as possible) to make sure the drum was as large as it was going to get. I measured this with my calipers and that turned out to be 2.090".
Now, I wanted the offset of the template guide to be small so I decided on 1/8". So, I added 0.125 to the OD of the drum and that was going to be the OD of my guide.
Also, I needed a second ring which would locate the base plate onto the sander table, based on the center of the spindle. So, I measured the spindle and that would be the center diameter of positioning ring.
Back to the MDF base plate. Using my Wells/Karol precision router base, I cut a shallow channel which the guide ring would sit in. Now, I wanted a tiny bit of clearance between the OD of the base plate channel and the rings, so I made that 0.003". This is where a CNC or even a lathe would be a good idea. But the MDF worked out alright.
Now that the OD of the base plate was cut, I then cut the ID out. Clearance between the sanding drum and the ID of the base plate, and guide ring I decided would be 0.045". So this made the ID .090" larger than the sanding drum.
So I cut the ID on the base plate and on the guide ring.
OK, so here are all the parts that I made.
Attachment:
OSS template guide 004.JPG
Here's the positioning ring in the base plate. I drilled and tapped for #10-32 machine screws in the OSS deck. This way I could ensure my new base plate was held solid, also based on the positioning ring.
Attachment:
OSS template guide 005.JPG
I also drilled and taped the positioning ring and the guide ring with a set screw to help keep it in place (again, steel or aluminum would be better for this too).
Attachment:
OSS template guide 007.JPG
Now, I screwed the base plate in place and the center of the guide ring Should be on the center of the spindle.
Attachment:
OSS template guide 008.JPG
Then I put the sanding drum on.
Attachment:
OSS template guide 009.JPG
And checked to see if my math worked out.
Attachment:
OSS template guide 010.JPG
Yup, I'm 1/8" offset from the drum. Just like I wanted
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I also made a template for my bridge shape, which was offset by 1/8" (having CAD capabilities makes this much easier).
Attachment:
OSS template guide 011.JPG
So, I attached a bridge (cut out to within 1/16" of final side) and had at it.
Attachment:
OSS template guide 012.JPG
