Rock chuck adapter question

[dehrlich]

I'm using a 1/2" rock chuck, so I have to use the 1/2 to 1/4 adapter just about all the time. I got a couple new "V" router bits with 1/4" shanks (can't seem to find any with 1/2" shanks, anyone know where to get them?). I used the 90 a couple times with no problem, but when I tried to use the 60 bit there was a problem. It was hard to get into the adapter so I sanded the shank a bit and got it in, but when I tried to put it in the chuck the adapter would not go all the way in. It got stuck about 3/8" from being all the way in. I sanded the shank a bit more, made sure everything was clean with the chuck and adapter but still no dice. So I went back to the old bit and it was fine. Anyone have this problem before? Variation in the shank diameter on the bit perhaps? They were on sale at Menards, perhaps that's why LOL.

[Digitalwoodshop]

I have Rocks and 1/2 and 1/4 inch ends. I solved that by getting all 1/4 inch shank bits.... Even the 3/8 Plunge End Mill Bit... I have the 1/2 if I need it.... That eliminates the sleeve issues....

I did get 2 in a batch of six 3/8 end mill bits from MCLS Bits that don't fit the 1/4 inch Rock... TOO Thick... Might be Metric...

If you ever go for the CT, I buy used Rocks.

AL

[spalted]

I'm not positive but I think CMT makes 1/2" shank V bits.

I have a rock chuck, but I don't recall having any trouble with any of my bits.

[lawrence]

make sure the pawl in your rock chuck is correctly twisted in place. You should not have to sand your bits at all to get them to fit- something sounds off mate.

As for 1/2 inch 60 degree bits- I love these cmt bits
http://www.amazon.com/CMT-858-501-11-Cutting-Diameter-16-Inch/dp/B000P4JOOY/ref=sr_1_3?ie=UTF8&qid=1363787152&sr=8-3&keywords=cmt+60+degree

Lawrence

[ktjwilliams]

With an ER20 spindle you don't have any of those problems !!! They accept any size from 1/16 to 1/2 " and everything in between with no ADAPTERS ...

[rjustice]

Hi Guys,
Just wanted to chime in here and give an answer to the original question. The tolerance on the Rock sleeves, and the bore in the bit adapters are extremely tight. This is to allow for the very least amount of runout (or wobble) in the spinning cutting bit possible. Runout is what relates back to vibration, surface finishes, tool life, spindle bearing life, heat generated in the bearings, noise levels, etc.

The industry standard is to have solid carbide cutting bit shanks be plus zero, minus .0004. I have seen many steel shanked bits be as much as plus or minus .001 on cheaper bits. On the other hand, most high Quality steel shank bits are generally right on size, or plus zero minus .0005. That is part of the reason higher quality bits cost more, it is because they hold tighter tolerances.

While this will not be fun, I do think it is acceptable to lightly sand, and/or stone the cheaper 1/2" shank steel shank bits that are problematic. If you use a coarser grit paper or stone, it will likely get tighter before you smooth it back off with something nice and fine like a 600 wetordry paper or a sharpening stone. Just try to do your re-sizing uniformly. In most cases you will be removing less than .001 of an inch, which is very little when you consider a human hair is only .003 thick.

Hope this helps...

[Capt Bruce]

I usually buy my V 60 and V 90 1/2" shank carbide bits at Eagle America on-line and they fit both the Rock Chuck and the CarveTight perfectly.

[Digitalwoodshop]

Just to add on sanding the router bit shaft... I have 2 in a group of 8 of the same size 3/8 bit with a 1/4 inch shaft that will not fit the 1/4 inch locking ring OR the Rock... SO it is possible you may have a 1/4 inch shaft bit that is oversized... Not the ROCK's fault in my case... It was poor QA on the bits.... Normally put in a Router and Cranked Down no one would notice... WE DO...

They came from MCLS..... Normally not a problem....


AL

[Dan-Woodman]

Grizzly also has 90 deg. V-bits right here in Missouri.