Thursday, April 23, 2020

Another Lathe (I Have a Problem)

Please, someone might need to run an intervention.  Yes, I have picked up my 5th lathe.  You read that right, I have five of them. I have two metal lathes (A South Bend Junior 9" [nick named a "Heavy 9" from 1929], and a South Bend Heavy 10 10L from 1957), and two wood lathes (make that three).  The new one is just like my first one - a Dunlap 1942 534.0601 Sears special, and the middle one was a little tiny cute thing that came with a bunch of motors and probably will do well turning pens and other small wooden objects.  In fact, I specifically targeted the Dunlap model because I know I can use the first one for spare parts as needed, it's a really high quality cast iron, and I can also even daisy chain the Dunlaps end to end and make some rods that are longer than the 3'6" maximum it provides.

Over the last few months, I've been building the lathe stand and refinishing the new old one.  I used machine spray paint on the last Dunlap, and I don't like the results, really.  This time I am using a brush-on enamel.  Both the stand and the lathe were painted with it.  I've been doing the assembly, and aside from the motor, this lathe is ready to run.  I did have an upgrade, though.

All parts came off.  This one even includes an upgrade.  The concept came from the South Bend Heavy 10 build, where you use a roller bearing as the take up washer instead of a brass washer.  This tiny wood lathe doesn't have a takeup washer.  I purchased




With it installed, I could adjust the tightness of the spindle turn until it had an acceptable amount of play with ease of rotation.

Next, I have to figure out how to attach the motor underneath this (inside the frame).  As this will use a link belt, I'm not worried about the belt "forming" or causing too much vibration.  I started out by taking a chunk of 3" found scrap aluminum (1" wide), cut it in half, milled the flat even flatter, then milled a notch on the opposite side.  I drilled holes to bolt it to some C channel, and one big one in each side to take a 7/16-14 tap.  This would become a clamping surface for the counter shaft and motor, without altering the stands structure.

I picked up a 7/16-14 left handed tap and die, and proceeded to cut the threads into these blocks (one left hand thread, one right hand thread).  Once I had them ready to go, I used a chunk of hex rod, threw it into the lathe, and rounded off each end (had to face it).  I put a right hand thread one one end, and then puckered up for the left hand thread on the opposite end.  This was my first job at cutting a left hand thread on the lathe.  Of course, I cheated.  Once I had the thread close, I used the die to finish it off for a perfect thread every time.


With the threads cut, I could start the assembly.  With opposite threads on each side, you can turn the hex bar one direction to tighten, or turn in the opposite direction to loosen.  I put the milled ends (I'll call them "nuts") on as far as they'd go onto the hex rod.


Then I could slide the assembly into place between the bars on the lathe stand, and expand the two nuts out.

From above the lathe

From below the lathe
Once tightened in place, it was absolutely solid.  Now, I know it will work.  I can build the bar next to hold the jack shaft bearings, and then put the counter shaft in place.  I'm still trying to figure out the motor-to-jack-shaft mechanism, but I'll cross that bridge when I get there.  I expect I will need to add a cover to prevent water or other liquids from entering the electrical motor.

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