Hitachi M12v problem -- Help!

[Alfred Clem]

I am cutting half-blind dovetails using a Porter-Cable 4112 jig and my Hitachi M12v router. I use the bit that came with ithe jig -- quarter-inch shaft. However, this bit keeps slipping out of the collet. After a lot of tinkering and getting the cutting depth to 9/16th of an inch as called for in the jig's instruction, I start cutting dovetails only to find the bit has slipped, exposing more of the bit than called for. I have cleaned the collet and the bit repeatedly. Granted the M12v has a difficult tightening mechanism. I try to get the shaft into the collet as tight as I can only to find when I start cutting that it has loosened and allowed the bit to slip. Wish I could use a bit with a half-inch shaft, but the jig only allows for a quarter-inch shaft. I'm about at my wits' end. Any suggestions? I'm a newbie on this forum and appreciate all criticisms and comments.

Alfred Clem

[Brad Ivers]

Alfred,

I have a M12V and have ran across this problem a couple of times, each time I've had this problem I solved it by doing the following. Make sure the slot in the 1/2" to 1/4" adapter is lined up with the slot in the 1/2" collet.
The few times I've had a bit slip I've noticed the slots weren't lined up. Seems if you keep them lined up the bit won't slip. My guess is, if the slots aren't lined up it weakens the available crimping power.

[George Summers]

Brad is right about lining up the slots. But you might also want to check that you are not letting the bit bottom out (with a longer shaft) or that you are not (with a shorter shaft) letting the head of the bit go all the way down to the collet so that you are trying to clamp right at the point where the head meets the shaft. Either way will lead to possible slippage of the bit.

George

[Ed Hilton]

My PC jig came with a steel bit. I don't remember what model number. The bit did not last long, and the power needed to cut the joints increased dramatically. I bought a carbide bit and it went much easier. maybe you have a dull bit and it is putting too much load on the collet.

[Roy Clarke]

I am cutting half-blind dovetails using a Porter-Cable 4112 jig and my Hitachi M12v router. I use the bit that came with ithe jig -- quarter-inch shaft. However, this bit keeps slipping out of the collet. After a lot of tinkering and getting the cutting depth to 9/16th of an inch as called for in the jig's instruction, I start cutting dovetails only to find the bit has slipped, exposing more of the bit than called for. I have cleaned the collet and the bit repeatedly. Granted the M12v has a difficult tightening mechanism. I try to get the shaft into the collet as tight as I can only to find when I start cutting that it has loosened and allowed the bit to slip. Wish I could use a bit with a half-inch shaft, but the jig only allows for a quarter-inch shaft. I'm about at my wits' end. Any suggestions? I'm a newbie on this forum and appreciate all criticisms and comments.

Alfred Clem

This is probably a bit late now, but you wouldn't have a bit with a 6mm shaft instead of 1/4" by any chance?

[Warren White]

I had exactly the same problem with my M12V, and I found that using an 8 mm bit was the answer. The hardwood I was using (cherry and maple) was causing the bit to chatter and loosen, despite my best efforts to tighten the collett. I hadn't had that problem with softer woods like pine.

I agree with what has been said about lining up the splits, but even that didn't seem to help. I purchased an 8 mm sleeve and bit and everything went well from then on.

I hope this helps!

[Alfred Clem]

Thanks, friends! All is well. I field-stripped the collet, the 1/4" adapter sleeve, and the bit. Then I washed all the parts using an old toothbrush and some paint thinner, inspecting all with a magnifying glass. Crud? You bet. Then I re-assembled these parts, taking care to line up the slots, and adjusting the bit to the precise height. Careful to tighten the bit as much as I could. Result: no slippage and cutting half-blind dovetails just as it all should. Thanks again for your advice, suggestions, and patience.

Al Clem
Sedona, AZ