View Full Version : Any one tried curved dovetails? (on pupose)

01-22-2013, 10:18 AM
I have one of those do nothing machines with the two crossed dovetail slots and a handcrank connected to two male sliders that reciprocate.

I got to thinking about a round one with the sliders chasing themselves.

Maybe split the base,start the dovetail then clamp the base together to finish the circle?

01-22-2013, 11:22 AM
Say what??


01-22-2013, 04:44 PM
You got a lathe? ;)


01-22-2013, 05:45 PM
Lathe and mill.
I was thinking of the mill and rotab to cut a circular female dovetail groove in a block of something(wood for the first try).
Then cut a male counterpart at the same radius to go round and round in the base.
I have never seen a curved dovetail and wondered 'Why not?'

01-22-2013, 05:50 PM
How do you arrange the gib strip?

Sounds a fun project


Lew Hartswick
01-22-2013, 06:06 PM
How do you arrange the gib strip?

Sounds a fun project


Gibs on a "do nothing" toy?????? Come on be serious. :-) What's the term.
"rattle fit". ? :-).

01-22-2013, 07:13 PM
the Christen drill grinder has one, or at least half of one.....the other side is flat. Its not a bearing, just part of adjustment mechanism. Does the Quorn grinder use one? or is that a round T slot?

01-22-2013, 07:38 PM
Angle plates and other rotary positioning tools often have a segment of a round dovetail in them. No reason you can't make your own. You could cut a hole in the bottom of the dovetail to put the chasing pieces in, then they would be retained by the crank from the top or you could plug the hole. If you make the dovetail at the top the same size or bigger than the dovetail cutter you could mill a circle with a regular end mill, then go down and in to cut the inside and down and out to cut the outside.

01-22-2013, 07:48 PM
The Quorn has what I'd call an annular T-slot. If we're stretching circular dovetails to include dovetail profiled T-slots, then I'm sure I've come across that before. It's possible the head on my Centec mill is secured in rotation by something like that. I can't see the advantage of that over genuine T-slots.

The only sensible application I can see for circular dovetails is when you want circular motion but you can't use the pivot area. Like those new-fangled motorcycle wheels with nothing in the middle.

01-22-2013, 08:52 PM
I have never seen a curved dovetail and wondered 'Why not?'

You have apparently never seen the way the compound mounts onto a South Bend lathe apron. Male circular dovetail.

01-23-2013, 08:47 PM
I like the hole in the bottom idea.Now,how to seal it up so people wonder how it was made?

01-23-2013, 09:05 PM
Use a close fitting plug and sand or otherwise finish to hide the circle. Are you making this out of wood or metal?

01-25-2013, 08:41 PM
I think the first attempt should be wood.
I think I will cut the curved slot wide enough that the cutter can go in from the top. Put the sliders in with a hole from the bottom, plug the hole,then send the cutter back in to clean up the plug.