Longer router bits

[guyos]

I am unable to use some of the jigs I made because of short bits.

I recently completed an adjustable box joint jig that has a material rest 1/2" deep, only to find my 3/8" and 1/4" bits too short even to clear the rest, I will try a collet extension, but the main problem is with my mortise jig.

My hand router is a 1/4" and the longest cutter I can find is 25mm. I have got a 1/4" deep plunge one from wealden, but I can't find a similar 3/8", does anyone know of a source for long cutters?

guyos

 

[David C]

A common problem.

Most router manufacturers and designers should be shot. They are not familiar with their use, and I fear you are unlucky in your choice of router.

I found Carbi Tool bits very useful as the have quite a number of long reach shanks in small sizes.

http://www.datapowertools.co.uk

David Charlesworth

 

[ike]

A 1/4" dia cutter anything much over an inch long should be used extremely carefully with small plunge cuts. They will vibrate at little more than light pressure and at worst will just snap. Beware.

A 1/2" dia, 1/2" shank straight cutter for kitchen tops is 2" long. That's about the safe limit for a TCT cutter I think - a 1:8 dia/length ratio.

Certain collet extenders (CMT I can vouch for) can also suffer vibration and flex with any more than a light cut.

cheers,

Ike

 

[philb]

Trend do a set of long cutters to suit their m&t jig in either 1/4" or 8mm shanks costing about £45

 

[guyos]

Thanks for the advice, I have found pocket hole cutters at Wealdens, which will do the job.

I am testing my box joint jig which is really accurate, but getting tearout on the front of the material - the back is OK, could this be down to wrong speed? I am using mid speed and a new cutter.

My router speeds 14000 - 31500 and I set it to middle.

guyos

 

[George_N]

I think that for small diameter bits like these you should have the speed at maximum for the cleanest cut. Tearout at the front might be down to the type of wood (B&Q type "whitewood " can be difficult/impossible to machine cleanly). I haven't seen the pocket hole cutter so can't comment on its suitability for this type of work but a regular two flute straight bit should do the job cleanly.

 

[Chris Knight]

Tearout can only be totally eliminated by using backers front and back of the baord you are cutting (one edge of the bit is always rotating the wrong way for a clean cut, when making through cuts).

 

[guyos]

Cheers George I will put the speed up.

Waterhead I can see the sense in using backing boards, only I never knew that it could be placed in front of the material. I have read lots of forums and articles on box joints and jigs but never saw any mention of it. I can't wait to try it, I am sure it is the answer to my wood tear out problem. Thanks

guyos