Using router bits for shaping

[Dsloan]

I just bought a used - but first for me - shopsmith mkV 500. It came with the shaping package but only one of the shaper cutters was with it. I know you can get a 1/2 router chuck so you can use 1/2 router bits. I've heard that it usually isn't a good ideal to use router bits in a shaper due to the RPM difference. But I would love to be able to use my 1/2 router bits. Is there anything unsafe about doing this? I would think that as long as you didn't try to feed boards too fast it would be ok but thought I would check before trying it.

[ChrisNeilan]

The Mark V can be used s a router, but the RPMs are kinda slow. Take little bites! If you use a speed changer, you can get away with it easier. The Power pro would be a better option, but the real deal is still a genuine router.

[jsburger]

I just bought a used - but first for me - shopsmith mkV 500. It came with the shaping package but only one of the shaper cutters was with it. I know you can get a 1/2 router chuck so you can use 1/2 router bits. I've heard that it usually isn't a good ideal to use router bits in a shaper due to the RPM difference. But I would love to be able to use my 1/2 router bits. Is there anything unsafe about doing this? I would think that as long as you didn't try to feed boards too fast it would be ok but thought I would check before trying it.

I don't know where you heard that. Cutter rotation speed is a function of the diameter of the cutter not the way (machine) it is rotated. The only difference between a router bit and a shaper cutter is the way it attaches to the motor. There is no difference between a dedicated shaper, my dedicated router table with a Porter Cable 7518 router or a Shopsmith.

The only issue with the SS is the lower speed. It is not an issue with large diameter bits but might be with small bits.

Routers came along to do hand held work that shapers had been doing for years. Now we have router tables that are basically shapers.

[Dsloan]

Thanks for the info fellas. I think the argument I heard about using router bits in a shaper was that router bits are designed to be run at higher speeds in the 20,000 to 30,000 rpm range while most shapers run in the 10,000 rpm range - and my shopsmith would be even slower than that. For router bits with only two flutes that aren't designed to prevent over feed I could see where there might be an issue with the bit taking too big of a bite. This could be more of a potential issue the slower the bit is spinning if you weren't careful about your feed rate. I never understood this argument though because most shaper cutters I've seen have bigger spaces between their cutters than router bits do. SO I didn't know if there was something else I was missing and wanted to check with folks that could speak from experience and not just opinions and theories.