camlock banjo design needed for wood lathe?

[Alistair Hosie]

Can anybody help me? I need to make a new banjo for my large woodturning lathe , and can't quite figure out the design for tha camlock and how they work.They have a large steel/metal rod running through them and when turned by an offset handle at the front this locks and frees the toolrest and banjo mechanism so that it can be pushed and pulled forwards and back please let me have the benefit of your wisdom.I have made a few good woodworking clamps with a camlock design but this running rod has me beat.I therefore request you my pals to help me if you can.Alistair

[rohart]

Better description needed, Alistair. For a start, what kind of banjo do you mean. I'm know about change gear banjos, but you surely don't mean this ?

I'm in the process of making some more camlock rods for my Dickson tool post. Do you mean something like that ?

I understand your dilemma, though. If you can't figure our how it works, how can you describe it.

Maybe this is something you folk in the wood fraternity are more familiar with.

And don't forget to tell us what colour it is !

[MGREEN]

Alistair,
Imagine your banjo (otherwise known as a tool rest base), as a long
narrow box with an open bottom.
The cam device could be as simple as a length of 1" O.D. pipe
with a longer length of 5/8" or so, round rod inside the pipe.
The banjo (box) needs a hole bored thru each end just a tad over 5/8"
for the rod to pass thru and be able to rotate.

Cut the pipe just short of the length of the inside of the banjo.
Drill two holes in the pipe inline with the length, one near each
end.
Insert the rod in the pipe and jam something in at each end to
temporarily keep the rod pressed against the I.D. where the
holes in the pipe have been drilled.
Transfer the pipe hole locations to the rod.

Remove the rod and drill and tap for screws.

The pipe will need to pass thru a part that will lift the plate that is
under the bed ways of the lathe.
This part will slide along the O.D. of the length of pipe inside the banjo, and
a bolt will pass thru the plate underneath the lathe bed and into the bottom of this part.

The part could be made from round or square stock.
It just needs to have a hole bored across near one end to receive
the pipe (a loose sliding fit) and a hole drilled and tapped in the other
end to receive the bolt.

Make the rod long enough to protrude a little past the rear end,
and protrude out the front and bent over for leverage, or make
a seperate handle for the front.

To assemble, lay the banjo upside down, slide the plate lifter part over the pipe near the middle(with the bolt hole end facing up),drop the pipe(drilled holes facing up) inside the banjo, insert the rod thru the front end of the banjo and pass it right thru the pipe and out the rear banjo hole.

Twist the rod until you see it's tapped holes line up with the pipe
holes and thread in some cap screws. tighten screws to pull the
rod hard against that side of the pipe I.D.

Make up and fasten(weld?) an appropriate block to one side near the front end of the banjo to receive the tool rest post diameter.

Clear as mud?
Mike Green

[john hobdeclipe]

The handle on the front of the banjo turns a shaft that runs the length of it, front to back. This shaft carries a long eccentric, which pulls a ring attached to the clamp.

Looky here:

http://www.ereplacementparts.com/delta-46305-1234-wood-lathe-parts-c-3275_9659_9660.html

and here:

http://www.ereplacementparts.com/delta-46543-type-1234-wood-lathe-parts-c-3275_9659_12804.html

In the first diagram, it appears that the hole in the back of the banjo is large enough for the eccentric to go through, and is then followed by part #53, a steel bushing. The bushing shows in the diagram, but isn't numbered.

[Alistair Hosie]

Wow thanks guys the plans show it but not in enough detail anyway I understand how most of it works other than the ring the rod goes through and what creates the cam.Otherwise this will just rotate as you turn the handle something must make it lift and the rod on one I have has a groove in it but beyond that I would like to understand better how the cam action works Rohart you probably know by now that the banjo is the part that the rest fits into and the banjo moves back and forward to allow for different dia of wood being turned.??Sorry I must be thick as an irishmans pork pie.Alistair

[ptjw7uk]

Alistair the cam is on rod 52, which at $127 is a bit pricy!

Peter

[rohart]

I'm beginning to understand the things you woodworkers get up to.

[Robin R]

Hi Alstair, I have taken some pictures of the banjo on my lathe, here are 3 of them. Basically the main shaft running through the housing has eccentric ends, with a lever that attaches outside the housing. The clamping action is on what amounts to an eye bolt, that is in the middle of the eccentric shaft when everything is assembled. The eye bolt has a nut and washer that go under the lathe bed and pull the banjo assembly down to the lathe bed, when the lever on the end is turned. I hope this is enough information to get you going. I do have some other pictures, but I don't think they really show anything more than the ones I have posted, but do ask if there are any other details you would like to see.

Robin