This Old Lathe

This Old Lathe - Part 3

Setting-up the Lathe

Before I mounted the motor into place I wanted to lift the inch and a half of plywood and level it just a bit more, as I could see that there was a slight twist across the table top.

The level was used more as a straight edge than to determine true level relative to the ground. As long as I wasn't twisting the bed or putting it under stress for fear that the casting may break or crack.

The motor has the 2-step pulley mounted on the counter shaft. The motor mount is bolted through the Plywood and oak tabletop with 4" 5/16 #18 carriage bolts from underneath.

The flat belt is actually a leather belt that is riveted together... Like a belt for loose pants...

The pulley alignment is poor, causing the belt to jump to the smaller drive size on the counter shaft if the spindle is stalled.

Once I get the 3-jaw chuck mounted and centered, I'll start onto a set of V-Groove pulleys to offset the alignment and get more power to the spindle.

I did eventually find a 1" by 12TPI (NF -National Fine) tap, right in town. After checking at numerous sources, and even being told that there was no such thread as 1" by 12TPI, it's either 8TPI or 14TPI I found a machine shop that agreed that the thread did exist years ago and likely fell out of use in the 1940's. The best they could do was to set-up a lathe and cut the threads on some Cold Rolled Steel Rod, and I could make the tap myself.

I was going to call them the following Monday when I checked back at a store that I try to get as many parts and fixtures from as possible and ran into one of the more seasoned sales people, who not only knew that the 12TPI was an older standard, but had the very tap I was after sitting on his desk from an order 5 years ago that never went through. Needless to say I was real pleased and got a hell'va deal at $30 CD as he was just glad to be rid of it.

With the Belt in place and the back plate threaded, machining on the lathe was a piece of cake.

The experience of having built my original lathe was paying back in spades with this unit as I had a real appreciation for the precision and features that were lacking on mine...

The cross-slide is dead on as the back plate is perfectly flat when faced off.

The outer edge was cut slightly over sized so that once all the coarse cutting was done I could slowly work inwards until I had the best fit I could against the chuck.

I was going to just use 1/4" NC18 bolts I had on hand but the heads wouldn't be recessed into the chuck, and the holes were 5/16ths so there would always be a way for things to work loose.

Obviously I waited through last week for a chance to get to the hardware store to get these 3" 5/16ths NC18 end-cap bolts. Which was really the right thing to do.

The punch that's shown sticking out of the chuck had to have it's knurling filled off while chucked into the drill press to bring it down to 5/16ths, ensuring an accurate mark to the center of the hole.

Rather than risk having the marks mis-aligned I punched, drilled and tapped the holes one at a time while the bolts went into place.

I've almost become obsessive about brushing off chips, and wiping down the plate as I work on it for fear that it ends up with skewed holes and taps.

To protect the face from being marred by the clamp I folded a scrap of paper a few times and placed it between the jaw and the plate.

Here it is all assembled...

I've fed a length of 1/2" diameter polished stainless steel rod to try the chuck out on. Steel is very different than Alum, it's almost like have to learn how to use the machine all over again.

The end that I've machined down is off-center ever so slightly, so I'll have to make a fixture to mount the dial indicator and determine which jaw is off and take it from there.

Support theworkshop.ca

Back to Machining