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delicate finishing challenge

Hi, i'm attempting to come up with a low tech way of fettling a rightangle of two metal plates joined together with double dovetail joints. The aim is to remove hammer peening marks and to obtain a precision rightangle. The problem is that if you use too heavy a method(files or wheels), it tears out the thinnest edges of the dovetails. I've accomplished a good stand of finish, but by using oil stones to slowly fettle each side of the right angle. This took me about 7 days to achieve, which is obviously crazy. Also the squareness is not great. Is there a tool or method out there that allows delicate hopefully jig held grinding so that i could get a precise 90 deg angle and at the same time, do it quite quickly(1 day maybe) and leave a good cosmetic finish? Many thanks in advance. Kindest regards, Nick.

Reply to
voltimando
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surface grinder?

Reply to
erik litchy

I would try a small angle grinder and a flap disc. See 44975-3VGA Chicago Electric at Harbor Freight. You may end up using oil stones but ought to be able to get close quickly.

Dan

Reply to
dcaster

=A044975-3VGA

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The difficulty with using an angle grinder is that it isn't precise enough to ensure squareness(looking for maybe 2 thou in 1 inch) and i've never used one before so that could end up with all kinds of disasters. The best that i've thought of coming up with is two adjustable gauge plates, set at a perfect 90 deg with varying gritts of glass paper, but again you're looking at maybe a weeks worth of work just to produce one workpiece. I guess it's a case of build it and see what kind of results are possible and then adapt as required. How 'considerate' are surface grinders to delicate edge joins? These sensible thing to do looks like build several test pieces and then try each method and see how things turn out. Thanks for taking the time to reply. Kindest regards, Nick.

Reply to
voltimando

A flap disc is a disc made with many flaps of sandpaper. They are very good at removing a small amount of metal such as smoothing a surface that has ball pein hammer marks. A hobby grade angle grinder is not very expensive, about twenty dollars. I think one would save you a lot of time in getting you very close to what you want.

Dan

Reply to
dcaster

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