Gallery, Projects and General > The Design Shop
Gear Depthing Tool Plans- ideas, suggestions, plans, machining order
raynerd:
Thanks for the suggestions...
BillTodd - I really really like the ball bearing suggestion! I know I'm being thick but I'm still not clear how they would be held and forced together. Obviously some have the obvious spring on the side bar I mentioned in my first post but I can't see how the others are spring closed without this. I understand the adjuster is putting pressure on the hinge, bar, ball bearings but what is holding them from just falling apart. Bill - also, why 4 bearings in each top corner?
This method would stop me needing to machine a parallel v groove for the bar hinge, I'd still need to machine, either mill a groove or bore a long parallel hole along each top side for the runners right.
The length of the depthing tool will be about 170mm long... That's a long way to bore two holes!! :bang:
BillTodd:
Well this is what I had in mind...
the balls would be a right PITA if not glued in position and the adjuster, as draw, is somewhat sub-optimal (i.e. a bodge)
balls are 4.5mm in 4mm holes. If the holes are drilled and reamed with the two plates clamped together the hole positions will align perfectly. All you need to do is drill them in the correct places.
rowbare:
Chris,
Perhaps using a flexure instead of a hinge would do the job. Mill grooves in the bottom of the two uprights and solder or epoxy in a strip of springy steel -- a bit of metal strapping might do the job. Mill a pair of grooves into a base plate and solder or epoxy the other side of the strips into it. You will have a fairly limited range of travel but it would probably be adequate for your needs.
If you really want to be fancy, for the adjusting screws you could make a differential screw from a 4mm coarse and a 6mm fine capscrew. Machine the head off of the 4mm and remove a cm or so of threads and drill a hole of an appropriate diameter and depth into the 6mm fastener. Press fit, loctite or solder the 4 mm bit into the 6mm. Put a post drilled and tapped with a 4mm coarse thread on one arm and one with a 6mm fine thread on the other. That would give you an effective screw pitch of .05 mm per turn. At least one of your posts would have to be removable for coarse adjustment. Might be overkill.
bob
BillTodd:
This version uses a spring from a cheap bull-dog clip
raynerd:
Bill that really is genius.
So you'd drill all holes with the two frames pinned together. Providing the two frames were set horizontal on the mill, I'm guessing it would ensure the runners are parallel.
Chris
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