Chipout with Dovetail Jig

[ssmith1627]

I have the HF dovetail jig and have made some attempts a while back with my PC router and a brand new dovetail bit.

You can see some attempts here:
http://ssmith1627.myphotoalbum.com/v...album01&page=2

Got some tight fits with my first couple attempts so I do have hope....lol. The alignments are way off but I can deal with that as I continue to learn to get it set up properly. No issues there.

But what about chipout ? It wasn't horrible but it did happen. These are just some scrap pieces of pine I was playing with but when I did try one in a piece of red oak it was really pretty bad. The pine results were much nicer.

Should I try a higher RPM setting for the router or a slower one ? Or would that even help ? And should I just try a straight bit first to do the bulk of the work and then go back with the dovetail bit ? Would that improve my results ?

Thanks for your feedback, as always !

Steve

[Lee4847]

Are you using a climb cut (right to left) for the first pass? When you make the first pass a climb cut the blade is turning into the wood and their is less chipout.

Lee

[gerti]

When starting make a straight pass across the front without actually going between the fingers. That helps!

[ssmith1627]

I started on the left side and moved right but going into the "fingers".

I'll take your suggestions and try making a pass along the edge first and then start into the fingers.

Many thanks.

Steve

[vaking]

Making the first pass right to left without going deep is a sound advice. Dovetail bit is small and calls for highest RPM router can deliver. The slower the RPM the higher chipout. Pre-cutting with straight bit is a standard practice for 9/16" dovetail bit. 1/2" bit does not need it.

[drumpriest]

These are all great suggestions, one other thing that you can do is put a piece of scrap on the right side of the boards to help prevent tear out on the last pin.

[pbrew]

Sacrificial 1/4" board

I saw on a woodworking show - Don't remember which one:

They used a 1/4 plywood or mdf board resting against the vertical board in the dovetail jig. That is between the clamps and the vertical board. The sacrificial board may chip out but your work pieces wont. I tried this myself and has worked very well.

[JimD]

pbrew's advice is good, that also works for me. If you consistently use drawer fronts of a given thickness you can screw a sacrifical board to the clamp arm of the dovetail jig and save having to mess with positioning two pieces. I have a piece screwed on that works for 1/2 inch bb plywood which I use for the drawer back (which I also dovetail). I climb cut the joint on the drawer front, usually, and sometimes put another sacrificial piece in (if climb cutting doesn't stop the chipout). If you wanted to get fancy, you could make the sacrificial piece you screw to the clamp arm adjustable for height. I haven't gone that far but a slot for the screw would probably be all I'd need to change. You only need about 1/4 inch height adjustment if you stay between 1/2 and 3/4 thicknesses.

Jim