Template routing - Pattern-cutting bits or Template Guide Bushings??

[RubEric]

I wish to route 16, 1inch wide, 15 inches long and 1/4 inch deep recesses in birch. I think it is a good application for plunge routing with a pattern.

I have a plunge router and both pattern bits (router bits with same size bearing 'above' the cutting edges), and template guide bushings. I hope those are the correct terms. I have ordered a square chisel to convert the round corners resulting from the router bit to square..

It seems there is little difference between the use of a pattern bit versus template guide bushings. The opening in the pattern has to be a little larger when using a router bushing but I see no other difference.

What are the advantages/disadvantages of one method over the other?? Which would you recommend??

TIA

Eric

[Unisaw A100]

Pattern bits onna 'count of the 1:1 relationship 'tween the template and the area being routed.

Also, it isn't always a problem, but there may/could be a slight "offness" with the collar in relationship to the bit due to there being the router, the base plate and the collar and any one of these could be off a little, not to mention the combined error if each is a "little" bit off.

Both have their uses/places but in this case I think the pattern bits win with a slight edge.

UA100

[George]

The "recess" is the key. To use a pattern-routing bit you'll have to have a top bearing, and your pattern will have to be pretty thick. You'll also want to be careful to either bore a start hole with a Forstner or a router bit with a plunging bottom. Not all pattern bits are capable of boring their own holes.

The objection to poor centering can be overcome by centering the bit (doh), or if your setup or equipment is so poorly aligned that you can't get it properly centered, you can rout by referencing the same quarter of the collar for critical dimension.

I've a Lee Valley router plate, properly centered, and love the ability to pattern rout on my table with a 1/4" template and almost any straight bit in my selection. If I want to use the router freehand, back to the Bosch.

BTW, your stated problem seems to be one for fencing, not pattern routing.

[Routerman P. Warner]

Some general information at the 2 links:

1) and 2) ****************************************************************> I wish to route 16, 1inch wide, 15 inches long and 1/4 inch deep recesses in