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Breaking Router Bits at the Shaft

5K views 24 replies 11 participants last post by  Cherryville Chuck 
#1 ·
I've only started learning to do dovetails and it's a real hit or miss for me. I own a Hitachi KM12VC and twice now while using a dovetailing bit on popular, I've broke the bit about 1/8" inside the end of the collet. Leaving about 3/4" of the shaft in the collet. This last one was bad enough the collet is a goner. I can't put another bit in it. I'm putting some pressure when tighting the bit so I don't think it's too loose. The back side of the head for the bit is just the dovetail collar so it's not rubbing. I'm at a loss. What can cause this?
 
#2 ·
Welcome to the Forum.

I'm a little new to routing but I have the same router. Been warned repeatedly by several sources not to insert the bit to deeply to where the collett tightens up on the bit collar. I always pull mine up just a little to where some of the shank shows.
This is just a guess, I'm sure someone more experienced will be along soon.
 
#3 ·
Hello and welcome. I have seen problems when the shaft is 1/4 in. and the steel is HHS, and not Carbide. tell me if those things are correct, I would use carbide, and check your speed, Also, don't use a lot of pressure on the bit. I did break bits when i used the 1/4 in. bits.
 
#4 ·
Welcome, Chizl...

One way to "protect" yourself from fully inserting the bit is to install a small rubber O-ring into the bottom of the collet. Then insert the bit loosely but up against the ring. I cannot take credit for that advice. A wise old Routologist told me that.
 
#10 ·
Ok, not to hijack the thread but after this was mentioned, I have to ask the question. "Is it really necessary to NOT install the bit to the bottom of the collet?" What happens if you do install it all the way down?

I didn't see anything about his in my operator manual. If you are not supposed to install the bit all the way down, then why wouldn't the manufacturer supply a rubber washer or other device?
 
#5 · (Edited)
im no pro, but i dont think the bit depth is causing the problem. something else seems to be going on.

i think Howard is closer to an explanation.
 
#6 ·
I don't think its the depth either since I'm doing dovetails and that requires me to have a collar, which in turn makes the bit stand out at least 1/2 away from the collet.

I'm not sure what type of bit, I'm just bying them at Home Depot, which seem to be the only one's they have.. But I'll make sure I get a Carbide next time.
 
#11 ·
hi David

i think there may be one manufacturer that doesnt recommend this. but every router ive got the manual says push the bit in all the way and then pull back out, varying from 1/8 to 1/4" i use a rubber sink washer behind my bit. the addition of a rubber spacer eliminates the need for measuring each time.
 
#15 ·
Hi Chiz

The jig that rockler is selling is the same one that many have,,from HF/Grizzly and many others that you can get for about 50.00 bucks.

ON SALE! - Complete Dovetail Jig, with FREE Dust Collector! - Rockler Woodworking Tools

The 1/2" is the diam.of the cutter ,most use a 1/4" shank bit,but it's best to use a LONG 1/4" shank dovetail bit on this jig..

Gives you just little bit more room inside router housing and in the brass guide..

With just a little bit of rework they work very well,see below :)

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#20 ·
I have used some of the Woodcraft bits. They are OK. I prefer to use Whiteside of Freud bits, and lately I have just been buying the Whiteside bits. I will try some discount bits (bought a few $5.00 Woodcraft bits and a few of the Holbren plywood bits on close out) but for dovetail I stay with the known quality bits.
 
#21 ·
Jointech problems??

I have tried repeatedly to contact someone at Jointech. They referred me to ezs@itoolscompany.com. I've corresponded with a person from there at least 6 times in the last six weeks or so. He seems sincere but it appears the company is in chaos. I get the feeling that no one knows what it going on as far as the 'ordering' and 'sending shipments' and 'availability of products'. What they :help:'DO' know is how to accept the money from Paypal. I sent them via Paypal for over $100 for my order and haven't received my full order.
Does anyone know if they are still in business or just unorganized.? I have registered a dispute with Paypal with no effect so far. It makes you not trust purchasing anything over the web through paypal or any other method.!

frustrated workworker
 
#23 ·
I picked up some 1/2" rubber grommets and inserted a couple in my 1/2" PC 7518 to follow Marc Sommerfeld's raised panel method Sommerfeld's Tools For Wood where they're used with matched bit sets and have just left them in place. With them there I drop the bit into the collet and let it bottom out on the grommet, which can compress easily as the collet tightens.

For any who have a deep collet (like mine) where a grommet isn't thick enough, I just added another grommet (or was it two more?) until it gave me the correct bit insertion.

It's a quick and easy, one-time action that only costs a few pennies and the issue goes away. The bit's always inserted properly too.

Check one, use many! :D
 

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