Dado use question

[Mark Rios]

Well, thanks to advise here I bought the Freud 508 (again) instead of the 608. I had a 508 a couple of years ago but I never used it and I sold it when I moved. While thinking about some cuts that I want to make I came to a question. If someone wants to cut a rabbet with a dado set, do you need to have some sort of sub-fence on the real fence? Otherwise, don't you run the risk of putting a nice partial circle groove on the fence and quickly dulling the nice, new, sharp edges on the blade?

If so, is MDF ok to use or is there a better material for the sub-fence?

Thanks for the help.

[John Hemenway]

Yes, use that sub-fence! Any straight wood would work. A scrap piece of 3/4 ply or MDF clamped to the fence works great. This way you can do 3/4 dados for shelves and rabbits and smaller rabbits for the back inset.

[Harry Goodwin]

Mark You need to attatch a sacrificial fence to your metal one for these rabbit cuts. Fasten the wood fence and raise the blade slowly with the saw running to get the cut out. Harry

[Chris Dodge]

Any wood will do for a sacrificial fence (as long as it is straight...this is critical!). I prefer to use something with a plastic laminate since the board I am cutting the rabbit on will slide more easily along a plastic laminate fence.

[Mark Rios]

Thanks very much for the confirmation. At lest that tells me that my thinking goes in the right direction some of the time anyway. :D :D :D

But now a follow-up question: Is mdf EXACTLY 3/4" or can I get laminate that is exactly 1/2" or 3/4" or 1"? If it's not exact the what about the tape rule on the fence rail? Or is that why I should make a scrap cut first? :D Resetting the tape on my older Ridgid TS2424 isn't an option (I don't think).

Thanks.

[Russ Filtz]

I never go by the tape rule. I always measure from the blade (unplugged!) or zero clearance insert hole. Use a dependable rigid metal ruler, not a tape measure or cheapo ruler. At least for critical cuts.

[Chris Dodge]

I never go by the tape rule. I always measure from the blade (unplugged!) or zero clearance insert hole. Use a dependable rigid metal ruler, not a tape measure or cheapo ruler. At least for critical cuts.

Same here. I agree completely!

[Jim Kountz]

I modified the cursor on my Bies fence to make it even more hairline than it was and when this type of fence is setup correctly its dead on. That said, when you make your aux fence you can simply plane the sacrificial face to a nice even measurement like 3/4' or in my case I made mine a full inch. This makes setting up the dado and rabbit cuts fast, easy and accurate. Just my method your mileage may vary.

[Mark Rios]

Thanks for the advice. Now I get to buy some more wood.:D :D :D