Question on stacking cutters with a ball bearing rub collar

[Ron Buck]

Long-timer lurker; new poster to SMC. Long-time WW but new shaper owner and I'm think I'm missing something obvious.

I've just purchased an Amana SC621 3 wing shaper cutter.


(note the catalog seems to be in error as dimension "d1" (inside diameter) is 1 3/4" on this cutter - not 2" as stated. Even at 1 3/4" the supplied reducer bushings still collide with the carbide)


I also bought their recommended ball bearing rub collar for the tool, but don't see how it is possible to stack it. If I purchase a 1 3/4" OD spacer (mine are all 2 1/32" for my 1 1/4" Felder) to sit between the bearing and other spacers/nut, the still bearing won't work. Seems a retainer is required to engage the inner bearing race, but the only retainer they sell is > than 2" in diameter making it unsuitable for the recommended 2" ball bearing rub collar. So what am I missing?


Sorry if this is obtuse; happy to clarify. Any help would be appreciated.

Ron

[Peter Quinn]

Do you have a basic shim kit? I'm pretty sure most of my shims are 1 3/4", you almost always need to stack a few shims between cutter and bearing to prevent interference on most cutters, always a good practice. My spacers and bushings are larger, though American spacers tend to be narrower than the European ones. So look for a shim set, pretty sure amana sells one.

[Peter Quinn]

I just checked my catalogue, amana sells 1 1/4" ID sleeve bushings with 1 3/4" OD that should also work for you, but you probably don't want to push the bearing up any higher than 1/8", I'd usually stack. 1/16" shim and a .030" shim at most.

[Ron Buck]

Thanks Peter. I Just spoke to Amana and they confirmed for me that the catalog was wrong (it is 1 3/4 instead of 2) and yeah, the bearing they provided wouldn't work for it. I think you're right, with enough shims and a different bearing (the race on the one they recommended for this cutter is only ~ 1/16" wide) I think I can make it work. Now the only issue is that the carbide intrudes on the 1 3/4" ID by a small amount and would need to be ground away. I don't think its enough to cause a balance issue.

[Peter Quinn]

Just realized this is a chamfer cutter, shouldn't matter if the bearing is a bit larger than the carbide, you just have to shim the correct bearing so it doesn't interact with the carbide, spins freely and allows the stack to tighten fully by holding the race down as a bushing. You don't want a cutter spinning free on a shaft, this can really damage a spindle quick by welding to the shaft then breaking free.... Damhik! You mostly control the depth of chamfer with the cutter height, so you can get away with a range of bearing diameters by adjusting your template thickness. If this is for straight work I don't bother with a bearing usually .

[Peter Quinn]

Thanks Peter. I Just spoke to Amana and they confirmed for me that the catalog was wrong (it is 1 3/4 instead of 2) and yeah, the bearing they provided wouldn't work for it. I think you're right, with enough shims and a different bearing (the race on the one they recommended for this cutter is only ~ 1/16" wide) I think I can make it work. Now the only issue is that the carbide intrudes on the 1 3/4" ID by a small amount and would need to be ground away. I don't think its enough to cause a balance issue.

Ron, I took a closer look at that cutter and my amana catalogue, looks like that is the correct bearing AFAICT, the small diameter, or the low side of the chamfer as viewed from above in standard is listed as 2", so the 2" bearing should handle that. That cutters is set up to run with the small diameter up in standard CCW rotation (counter cloak wise) when feeding from left to right, you generally want the bearing above the work and the pattern above the work on a shaper for safety, a bit more material between your hands and the cutter should things get strange, but there are lots of exceptions and it works either way. For a circle in challenging wood you might have to run part in one direction, then flip both the work and the cutter then run in the opposite rotation and feed from the opposite side so you are always running down hill versus the grain, and never climb cutting freehand. I'll climb a chamfer on a router freehand with a bearing bit but not on a shaper. Make sense? Try putting the bearing on the opposite side of that cutter and see if that lines up.

This set is pretty handy to own too......http://www.toolstoday.com/p-6111-8-p...r-cutters.aspx

[Ron Buck]

Thanks for your help, Peter. As soon as I can get enough shims to clear the carbide on the cutter with the bearing, I'll give it a spin (!) I'm working on an inside curve to a molding, so a template will be used.