Dovetail angles

I was going to make some stops for the mill table. I thought it would be
simple to mill a slot in an appropriate size metal and mill female
dovetails, set-screws and Bob's your uncle. Might even throw in a brass gib.
However, when I measured the male dovetail angles they are 55 degrees. To my
knowledge there are only 60 and 45 degree cutters commonly available. So the
questions are:
1) Is this usual?
2) Would you mill a 60 degree female dovetail and accept the disparity
(after all it is only a piece of iron to stop the table going any further -
nothing magical about it)?
3) Would you seek a wise Sifu in the Sinkiang province for only he knows the
ways of 55 degree dovetail cutters?
4) "Sod it, I am going to make do without stops!"
5) Devise different stops altogether (magnets, adjustable bars like on taig
lathe, etc.)?
Thanks,
Reply to
Michael Koblic
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Tapered gibs .
Reply to
Terry Coombs
I'd mill the angle on a separate piece and screw and pin it to the body of the clamp. That way you can make any angle you like by tipping the piece in the mill vise.
Reply to
Ned Simmons
Simpler still, clamp the stop-to-be at 5 degrees to the horizontal and mill the 55degree dovetail directly with the 60 degree cutter :-)
Mark Rand RTFM
Reply to
Mark Rand
6) Use your shaper, set the tool angle to 55. Easy.
Pete Keillor
Reply to
Pete Keillor
Sifu's grandchildren makes these things:
I like the 30mm thick blocks because they make a more stable stack than the thin ones. Tthe 55 degree stack (30+15+10) on the table in front of me is 2-1/4" high at the lowest corner of the work, too high for my milling vise. I'd clamp the pile to an angle plate and use it to make a low 55 degree plate I could use in the vise.
Here's my answer to a similar problem:
Jim Wilkins
Reply to
Jim Wilkins
Dovetails come in a number of angles and 55 deg. is one of them. To mill a matching dovetail, if you have a bridgeport type mill I would just tilt the head to the proper angle. Another way would to just use a round piece of brass stock and clamp it into the dovetail or a half round piece.
John
Reply to
john
That'll work (with a 45 degree cutter), but won't clean the surface under the overhang without a second setup -- not a big deal. The other possibility is to use a regular endmill and live with an undercut perpendicular to the 55 degree wall.
I hope Michael understands our ramblings.
Reply to
Ned Simmons
Thank you! I like low tech. My skill set should just about cope :-)
Reply to
Michael Koblic
I am afraid you lost me. How does the wrench fit into this? OTOH it gives me an idea: Some sort of split nut on the leadscrew rather than the stop on the ways?
Reply to
Michael Koblic
Not very common, but I believe that is the angle for Sherline ways. (Or is it that Taig/Peatol?)
No. Your stop will tilt when it is hit.
No. But perhaps find someone with a Tool and Cutter grinder, and have him modify a 60 degree dovetail cutter to become a 55 degree one. (The cutter will be weaker than a 60 degree one, of course.
No.
Probably not.
Can you tilt the Mill's head? Tilt it by five degrees, and you can subtract that angle from the 60 degree cutter. (Except that you may need to undercut things to clear the other side of the cutter. Hmm ... use a 45 degree cutter with a tilted head. Or tilt the workpiece with a 10 degree tilt in the mill vise. (You'll have to re-setup for the other side, of course.
Do you have a friend with a (metal, not wood) shaper? That is the machine to use for creating strange dovetail angles. You can do it with plain HSS lathe bits which you grind to shape.
Good Luck, DoN.
Reply to
DoN. Nichols
Perhaps you lost me too. I read your post to mean that you had a male dovetail shape standing proud from the mill and wanted to cut a female dovetail slot to fit onto it. The tool I showed you has a difficult internal hex shape split into two easily milled halves. Replace the hex with the two halves of the dovetail.
If you change the brass locating pin to a screw that pushes on the other piece, you could adjust the two screws to make the clamp bear evenly on the dovetail sides even if it wasn't machined exactly. Slot the large end of the female dovetail for a Woodruff key which will float into alignment with the flat on the end of the male dovetail.
Wakarimaska?
Or you could make simpler, less rigid clamps that hold dial indicators and mill to a reading rather than the somewhat uncertain increased handle resistance when you hit the stop.
Jim Wilkins
Reply to
Jim Wilkins
Hai, wakaru to omoimasu.
Right. I did not make the connection. I am keeping the indicator idea as a plan B - I have a nice little magnetic holder on order for just that purpose. Or even a combination of methods. It's just that the dovetail angles threw me...
Still, it is refereshing to get a bunch of different answers with none of them containing the phrase "You need a lathe!"
Reply to
Michael Koblic
Indeed. Simple as can be.
Gunner
Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them.
Reply to
Gunner Asch

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