Router bit selection for.....

[bean438]

1. Cutting circles with my Jasper circle jig. Instructions say to use a 1/4" bit. All I have is a 1/4" straight bit. I have read to use upward spiral, and downward spiral. Bill even said a spiral goes through 1/2" like as hot knife through butter.

2. Trimming SLA curve top and bottom flush with the sides. I know it is a bottom bearing flush trim bit, but 1/4? 3/8? 1/2?

[Harley]

1. Cutting circles with my Jasper circle jig. Instructions say to use a 1/4" bit. All I have is a 1/4" straight bit. I have read to use upward spiral, and downward spiral. Bill even said a spiral goes through 1/2" like as hot knife through butter.

1/4" straight will do fine but the upward spiral works better. If you can drop the cash, Leland has good ones but they do cost. I build a lot of cabs and I use a 1/4" straight with my Jasper if that puts you at ease.

2. Trimming SLA curve top and bottom flush with the sides. I know it is a bottom bearing flush trim bit, but 1/4? 3/8? 1/2?

The bigger the dia, the faster the cut speed and the cooler the bit runs. I use 1/2"

[bean438]

Thanks Harley.

Can I do this all in one pass, or am I better off making multiple passes, going deeper each time?

1/2", 3/4" plywood is what I will be trimming and making circles in.

[LelandCrooks]

2 passes 1/2, 3 passes 3/4. Don't crowd the bit. If you hear it chatter you're going too fast. They can break.

It will do 1/2 in a pass, but it's hard on the bit.