Thread: Hitachi Router TR-12 Collet problem

If possible, completely disassemble the collet and give it a good clean. Try inserting a ½" bit while it is disassembled. It is probably just tight/compressed from having a bit installed for so long. If you can't get it to open up you should be able to get a new collet as a spare part.

I did that. Even with the collet removed and cleaned the half inch bit will not go in. I found some photos on the Net of the original Australian packaging and on the box it states both 1/2" and 12mm so I'm still not sure what diameter it is supposed to be. . The cheapest new collet I've found is $104 which would certainly up the cost of the router.

I have this router, and initially had trouble extracting bits from the collet. Then I learned that the collet has to be turned by spanner ONCE until it is free, then turned again. It will momentarily tighten, then become loose, and the bit can be easily withdrawn by hand. You may not have followed this procedure initially which might be the cause of the problem. If you can get a bit back in, do so, then try the two-stage removal process.

Thanks - but even with the collet right off it's too tight a fit. Previous owner says it had not been used for 5 years so it has had a bit tightened up in it for that long. I think the metal has lost it's springiness and is not opening out when loosened.

So did your TR12 come with a 1/2" collet?

Yes. And I bought mine second-hand with bit installed. I had difficulty in removing the bit, and, because I did not know any better, I originally got the bit out by tapping it with a wooden mallet! I then had a lot of trouble getting the bit back in. Eventually I fitted the insert with judicious use of the mallet, reassembed the whole fitting, and replaced it on the router. Since then I have removed and replaced bits very easily using the two-stage procedure. The usual bits I use are Whiteside bits from the USA:they are easily the best I've ever used.

It does sound similar circumstances but I tried again to no avail. Thanks for taking the time to reply.

Does the bit you got out have a 1/2" shank?

Originally Posted by Treecycle

Does the bit you got out have a 1/2" shank?

Yes

Have you separated the collet from the nut? If you undo the nut completely and remove, the collet is attached, but will unclip from the nut (usually). if you have taken off the nut, but the silver collet remains in the router, then it will be compressed, gentle persuasion will remove it from the machine.

There may be some rust sticking the two together preventing the collet opening properly.

If a 12.7 bit came out, then it is a 12.7 collet.

I have 12mm router bits for my festool router and they would simply fall out of a 12.7 collet.

The bit that came out should fit back in, regardless of its diameter. Completely remove the nut from the router. Then prise out the collet which is inside the nut, and is removable. When you have the collet out, you should be able to expand it over the shank of the original bit' perhaps tapping it with a soft-faced mallet. After all, it fitted there previously: Why not again? Work it on and off a few times, then reassemble the unit by putting the nut on the bit first, then the collet. Then screw the unit to the router, and tighten. Then undo, using the two-stage process described previously. That's what I did, and everything now works like a charm.

OK I can persuade a bit to go in if using a mallet. Will try doing so repeatedly in hop of stretching it open a little. I've attached a photograph which will explain the problem better than I can. Thanks for the helpful suggestions.

Hitachi-TR12-Collet.jpg

It appears that it must be a 1/2" collet by the measurement on your caliper of 12.58mm. If it was only a 12mm collet, I don't believe it would be that big otherwise a 12mm shank bit would just fall out unless you were holding it as you tightened. Maybe a previous owner has tightened the collet down on to a 12mm bit and actually deformed it so it doesn't open back up fully to 1/2" when released. Does it measure the same if you take 2 measurements at 90 deg to each other. Take one where the collet is split right through the side, and then another one at 90 deg to that. If they are not the same, then it has been deformed. If this is the case you could try driving something a bit larger in diameter down the bore a bit to try to spread it again and get it round. Make sure you protect the thread by placing it on a piece of wood or plastic. Another way to spread it would be to gently drive a small wedge into the split.
As I said, be careful, and don't go too far without checking after each try. Good luck.

Been awhile since I've used mine but from memory the bits were always a firm fit in it, I'd just leave the collet sitting out for a day or two or carefully drive a timber wedge in the split to open it a bit and leave for a day or two

Earlier on I took a socket (as in socket wrench socket) with a diameter of 12.8mm an hammered it in with a mallet. I'll leave it overnight and check it out tomorrow sometime.

Thanks again folks for the helpful comments.