Mystery Project...

Oh yeah, for sure. Just haven't gotten to it.

BTW: Still waiting for the little endmills to finish the rack gear.


Ray

Gee Ray, I am a little surprised you didn't knurl or put a hex on the end for ease of turning. Any plans on that upgrade? The project is looking very good, keep 'em coming.
 
Here's more work on the transit gear mechanism. Normally I like to design things up front but, this was laid out the old fashioned way because there's almost no room to measure the clearances between the rack gear on the lathe and the leadscrew. This thing is driven off the rack gear and must clear the leadscrew. After looking closely at the available space, I decided the main drive gear would have to be smaller than the 2:1 ratio I was looking for and also, I had to double stack the gears to get it to fit. Anyhow, the brass rack gear is 15 tooth and the drive gear was 20. I'm hoping it won't be too slow to operate and also have decent torque. Things are fitting well and the gears are all meshing smoothly but I won't know if I like the feel of it till later...

Here's the gears. The teeth on the large gear are the same angle but the reflection from the chamfer shows-up oddly. The gears mesh nicely. Didn't have a 2" piece of brass so, it was made of 1045 HR.


Transit Gears 0.JPG

Here's the back side of the transit mechanism. A well fitting spacer was made and welded to the plate to give the correct engagement with the rack. The little studs were custom made and have crowns that fit in a recess to hold the gears in place.

Transit Gears 1.JPG

Here's how it fits with the gear rack. A handle drives the steel gear which then drives the brass gear. I could have gone with one gear but I wanted the handle to spin and move the same way as the carriage. The top view shows how their double-stacked and the side view show that things are clearing the leadscrew by almost 1/4". Also, with this angled mechanism, the new tailstock will be able to enter fully into the rear U-shaped section of the carriage and neither the transit gears or drive wheel will interfere with the thread chaser. Matter of fact, the transit gears fit well behind the chaser. I'll use snap rings and washers to keep the studs snug. I still need to broach the steel gear and cut a keyway on it's corresponding stud.

Transit Gears 2.JPGTransit Gears 3.JPG

Just a few more details to go on this -not much. Need to rig-up a bracket to connect the transit mechanism to the tailstock then make a wheel. I'll probably incorporate that tensioning mechanism (discussed in an earlier post) to this bracket.


That's it for now...

Ray

Transit Gears 0.JPG Transit Gears 1.JPG Transit Gears 2.JPG Transit Gears 3.JPG
 
We're getting there. The bracket is all done. Just need to install the snap rings on the axle studs and make a wheel. It glides back/forth nicely so far with no sticking at all. Gotta cook Sunday vittles on the BBQ now. Probably will finish this later this evening. After that, it's just the tensioning bar and some alignment of the turret taper blocks...

Base1.JPGBase2.JPGBase3.JPG


Ray

Base1.JPG Base2.JPG Base3.JPG
 
Great work so far Ray. At this point I would have done only one thing differently. It looks as if you have already bored the tooling blocks correct? If so now you have to align them to the chuck. I would have waited till they were all mounted and the last operation to complete the Turret would have been to use the lathe chuck to bore the holes. Perfect alignment that way.

"Billy G"
 
Thanks Bill but there's a setback on this... Everything works and rolls fine but, there's not enough gearing leverage to drill holes. The hand crank works very smoothly but, it takes way too much hand force to drill so, I'm going to fall-back to plan-B (which I had to hurry-up and invent). Plan B-1 is to put a wheel crank in one or more of the blocks or, plan B-2 is to devise a leverage bar or an ACME screw mechanism to drive the whole unit forward. ...Going to sleep on it to help make the decision...

On a positive note, when drilling, the unit did not lift up at all so, that tensioning mechanism might not be needed.


Ray
 
Use a spider type handle. A 3 0r 4 inch hub with 4 arms sticking out of it. The arms must be at least 1/2 inch dia. The length of them will determine the amount of force you have available. The longer the more force you can apply. Put a ball on each of them.

"Billy G"
 
Ray, have you considered moving the drive train to the outside of that bracket? (brass gear stays where it is, but is driven from the other side). That would require some refabrication too, but would solve the problem of the gear size limiting your available ratio.
 
great job

Thanks...

Bill's idea worked. Complicating matters, I happened to grab a bit that was a little dull. 20 seconds at the grinder and it wasn't dull anymore and drilled through no problem but... I want a cleaner solution and think I'll abandon the gears and drive it with an ACME rod from underneath and between the ways.

Here's a piece of 1" stock (pretend it's an ACME rod) laying in the intended location. Plenty of space with room to spare. There's already a drilled/tapped hole at the end of the bed which served a stop-bolt to prevent accidentally pushing the TS off the end of the bed. That hole will serve as a good mounting location for the thrust plate. I'll make a small fixture with an ACME nut welded to it that will attach to the bottom of the TS. The TS can now be moved with either a hand crank or a motor at the end of the lathe. If I feel like getting fancy, instead of an ACME nut, I could make a half-nut doo-dad so I could optionally disengage the half-nut and slide the TS by hand as desired.

Threaded ACME rod is cheap... 20 bucks for a 3' piece... Clean approach and drilling depths can easily be estimated by counting the number of turns once contact is made.

What'ya think?

Acme Thrust location .JPGAcme rod location.JPG

Ray

Acme rod location.JPG Acme Thrust location .JPG
 
Well, I think this will be much better. It was just made this morning... I decided to try a drive rod mechanism with a half-nut clamp.

Here's the half-nut clamp. I just made it out of a couple 5/8" nuts and a simple door-hinge like closing bracket.
HN 1.JPGHN 2.JPG

And here's how it looks. It's not all assembled yet -we're just a few steps away from that.
HN Drive Bracket.JPGHN Drive Rod.JPG

Time to have lunch and walk the dogs...

Ray

HN 1.JPG HN 2.JPG HN Drive Bracket.JPG HN Drive Rod.JPG
 
Back
Top