Dovetail matching tail n pin bits

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3 Sep 2022
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Just purchased a Porter Cable dovetail jig. It came with 1/2 & 1/4 shank bits for tails and pins.
I have my 1/2 router in my table, yes I can take it out.
I also have a palm router that takes 1/4 & 8mm shanks.
I'm hoping to use the palm router and have found 8mm shank tail bits with depth and diameter heads matching the 1/2 shank bits supplied.
(Supplied 1/4 shank heads are too small to cut through 15mm thick stock)
Having found 8mm shank with the cutting head near identical to the supplied 1/2 shank bit.
My question is do I have to use a matching straight bit to cut the pins.
The jig was supplied with what appears in my opinion matching bits.
The diameter of the tail bit is of course wider than the straight.
Is there a ratio to consider?
The Porter Cable jig also comes with guide bushes that match the jigs templets I think this is a typo in the manual, shouldn't it read templates?
Ultimately I'd like to know how critical the diameter size ratio between the two bits are.
I feel given it appears I need to use the guide bushes if the straight bit is not correct the pins will be either too tight or loose.
I'm hoping I'm wrong though making this an easy question to answer.
Or what if I didn't use the guide bushes and used bits with rollers?
Any help gratefully received, cheers Simon
I've only ever had a cheapo version but on that the dovetail bit did dovetails, and straight bit did box joints. Don't see why an 8mm shank bit wouldn't work with the ½ inch bush as long as the length, diameter and angle all match. If not you'll need to get one that matches the angle and depth then calculate the bush size. Measure the diameter of the bush for the ½ inch bit and take off half the difference in diameter between the ½ inch and the 8mm, that's the size bush you need.
So if the bush was 20mm and the difference in bit diameter is 4mm you need an 18mm bush to get the same result, hope that makes sense