Manufacturing a dovetail

[The Warthog]

The wooden dovetail that held my telescope onto the mount was getting a little worn, due to my habit of overtightening the screw. I decided I needed a new one, and didn`t want to pay the amounts they ask for, for a metal one.

The old one was oak, and I decided to use maple, as it is even harder. The first photo shows the old dovetail and the damage from the setscrew.

I used the old dovetail to set the angle of the blade (photo 2.) The angle is about 75º. Then I ripped the 12 inch piece ofwood I was cutting from in the saw, using the old dovetail as a guide to set the distance of the rip fence.

I now had a 12 inch dovetail, the same as the old one, but I didn`t wnat it that long, so I cut it neatly into a 4½ inch piece, and a 7½ inch piece. The shorter length of the dovetail will give me more range to move the scope up and down for heavier eps.

I used the old dovetail again to set both the depth of the rabbet at the end of the dovetail, and the length of the rabbet (photo 3,) then I cut the rabbet by making several passes, moving the work towards the end a little more after each pass. This took about 16 passes, but resulted in a fairly smooth rabbet. I could have done this with a router, but didn`t feel like setting up another tool.

With this done, I sanded the saw marks off the pieces, and put them down on a tarp and sprayed with about four coats of Varathane clear varnish. (photo 4)

Then I took the shorter piece, drilled a ¼ inch hole right in the middle, countersunk it, and put in a ¼-20 screw. This is to mount my little Mak on the EQ3-2. (photo 5)

[The Warthog]

Then I drilled a 3/16 hole in each end for the mounting rings, using the old dovetail as a template. (photo 6)

Done! (photo 7) And the Mak with its new dovetail, mounted on the tripod. (photo 8)

Total cost, less than $7.00

[barkis]

Wood, what a wonderful medium. It's versatility can rarely be matched, and such a pleasure to work with.

You have the stuff in abundance in Canada too WH.

Great job with the dovetail. Could you not utilise a metal plate to take the brunt of the clamp screws. It would perhaps give a longer life to the dovetail. Just a thought, but I'm sure that idea will already have crossed your mind.

Ron.

[The Warthog]

Actually, the metal plate idea did occur to me, but I'm too lazy to follow it up. I chose maple because of its hardness, even harder than oak and capable of dulling a drill bit in short order. I'll try not to tighten the screw so much, as a light pressure is adequate.

I need to figure out why the saw blade is being a bit rough, and making burn marks on the wood. I change the blade last year, from a 36-tooth blade to a 40, of about the same quality. The old blade gave me much smoother cuts until it got a bit dull. I don't know if it's the blade, or if I'm doing something different.

[barkis]

More teeth means a finer cut, but perhaps the friction has increased as a result. A pretty poor explanation really. Must be some other cause.

[steve51450]

less teeth will stop the burning as to many teeth will cause friction when cutting hard material like maple, a multi toothed blade is better for cutting softwood and mdf etc

[The Warthog]

Well, thanks! I'll go to a coarser blade, and see how that works out.

[philsail1]

Nice job you did there "Warthog."

As good as a metal Dovetail - and for a fraction of the price too!

Great satisfaction when you make something yourself.

Your idea has given me (and I'm sure many others) inspiration.

Regards,

philsail1

philsail1

[PhillyDee]

I like the wooden approach, but as a metal worker I choose Aluminium every time! Even though wood is so much easier, and yet sometimes more difficult to work with. On another note, you could try a variable pitched blade? I have no idea if you can get them for circular saws though!