Follow the blinky light.

I’ve been surfing around looking  the net looking for some idea’s for my radial arm saw reprap project.     Initially,  I was thinking that a belt drive would be the way to go, but than I thought it would be interesting us a rack a pinion.     It seems like racks and pinions arrangements are a bit pricey so that got me thinking about making a rack with my cnc metal shaper project.  It would be nice to have a clapper that could have a fixed automatic downfeed to it so I it would be easy to make a rack.   Something basically that could do a simple automatic down feed to a fixed depth.

I have functional Ammco shaper as well as a a carcass of a parted out Ammco metal shaper I picked up cheap  off of ebay.   I want keep one shaper classic so to speak and basically pimp out the carcass with cnc.

The plan is to basically to machine a new clapper assembly specifically to mount a stepper motor.    I figured this would be a project that I could mount on my classic shaper and get use out of, while I get the rest of pimpy made.   I probably should be do this out of cast iron, but I’m using steel that I have on hand instead… (I hope I don’t regret that).  The first piece that I’m working on machining is the dovetail assembly that fits into the ram.     I got a piece of 4″ round and offset it in my 4 jaw chuck.   It was a interesting experience since my lathe isn’t bolt to the floor.  The vibration from the imbalance was causing it to walk.     I was getting pretty good surface finish with carbide but it seems like my poor logan is groaning a bit with the increased cutting forces.  So… I switched back HSS using my diamond tool holder.  I’m experience some pretty bad tearing with that.  I’m still roughing things out on the first side (which fits into the ram).   I basically need a 1.125 tight fitting diameter.    I don’t know if I can achieve that turning.  I did a quick check for taper and it seems like lathe is cutting straight, so I’m wondering if I should go to size with tool post grinder.   Hopefully, I can grind it straight enough that I wound have to do this from centers…

In the mean time, the thing that got me started down this path,  a rack and pinion for my radial arm saw reprap has presented itself with another solution.   I’ve seen people making rack drives from threaded rod.    In researching this I across some posts from Mike Everman on making a fixture for machining the pinion racks.    This guy has done a bunch of things that I find rather interesting….  Here are some links…

Fixture for makeing a gear to mesh with threaded rod.

Very interesting belt drive application

Differential Roller Screw

Servo Nut Drive.

oldham coupling animation.

Eddy Current Brake

Anyway  I go this threaded rod rack route, I have some acme rod from a scrapped garage door opener that would be fun to use.   Using a fixture/tap solution unfortunately wouldn’t work.

In that cnczone there’s an interesting link on threading in the lathe.  At some point this would be fun to try.  Anyway… rapidly running out of christmas vacation ;(

One other very interesting post I’ve run across was this:



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