NEWLY-ACQUIRED JET 1236PS

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Steggy
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Re: NEWLY-ACQUIRED JET 1236PS

Post by Steggy »

BigDumbDinosaur wrote: Mon Aug 24, 2020 1:59 pm
GlennW wrote: Mon Aug 24, 2020 12:54 pmInteresting!

The previous owner must have added it. Mine relied on the motor weight, hence the cast iron 75 pound motor on a hinged base.
It appears to be OEM. There is a tab cast into the motor mount plate and that tab was drilled and tapped to accept the shoulder bolt. The adjusting link also appears to be an OEM part. Next time I have the camera out I'll take a picture so you can see.
Here are a couple of photos of the motor mount, complete with OEM belt tensioner.

belt_tensioning01.jpg
belt_tensioning02.jpg
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GlennW
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Re: NEWLY-ACQUIRED JET 1236PS

Post by GlennW »

That's a nice feature. Thanks for that!

Mine is the earlier version without the adjuster...
DSC02797.JPG
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Steggy
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Re: NEWLY-ACQUIRED JET 1236PS

Post by Steggy »

GlennW wrote: Mon Aug 31, 2020 2:37 pm That's a nice feature. Thanks for that!

Mine is the earlier version without the adjuster...

DSC02797.JPG
Your motor appears to be physically smaller as well. Does it bounce around while the machine is running?
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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GlennW
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Re: NEWLY-ACQUIRED JET 1236PS

Post by GlennW »

Sure does bounce. The original cast motor died and I had to replace it with a standard motor which weighs much less. It was fine with the heavy original motor.

I just use a Vise Grip C-clamp to tension the motor belt to make it work, as I seldom use this lathe.
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Bill Shields
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Re: NEWLY-ACQUIRED JET 1236PS

Post by Bill Shields »

i put a bolt up from underneath with a large washer and giant spring to help tension...
Too many things going on to bother listing them.
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Re: NEWLY-ACQUIRED JET 1236PS

Post by Steggy »

I gotta say one thing. The folks in Taiwan who built this machine have strange ideas about electric motors.

The motor's frame is slightly bigger than a NEMA 145T, but has a shaft that is 18mm diameter—a 145T unit has a 7/8" shaft. The mounting bolt pattern is nothing like any standard NEMA frame and there is enough iron in the motor to sink a small boat. If weight were horsepower, this motor could spot loaded freight cars on a team track. :D The split-capacitor design is worrisome: neither cap is something that can be locally procured. While the motor can be made to run without the capacitors, it would be lacking power and would become an energy hog.

In any case, I've never been fond of integral horsepower, single-phase motors, especially weird ones made on the other side of the Pacific Ocean. Ergo I'm going to work out how to re-power the unit with a motor that doesn't weigh a ton, take up the space of a EMD prime mover and suck up juice like an arc welder.
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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Bill Shields
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Re: NEWLY-ACQUIRED JET 1236PS

Post by Bill Shields »

But....they are cheap to make with local talent and materials...and what do they care about power consumption.

Besides the big motor helps keep the belt tension up.
Too many things going on to bother listing them.
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ctwo
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Re: NEWLY-ACQUIRED JET 1236PS

Post by ctwo »

Mine came with a 1/4 HP fan motor and welders clamp for the belt tensioner. lol But actually the guy had a case 3-phase motor kicking around that he tossed into the deal. I really should find some motivation and weld up some legs for it and get it into operation. I use my 10" logan more than my mill and often want a larger spindle bore.

And you might consider cross drilling the chuck backing plate and thread for a set screw to stop it from unscrewing - of course using a copper plug or something on the spindle thread.
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Re: NEWLY-ACQUIRED JET 1236PS

Post by Steggy »

ctwo wrote: Thu Sep 03, 2020 10:52 amAnd you might consider cross drilling the chuck backing plate and thread for a set screw to stop it from unscrewing - of course using a copper plug or something on the spindle thread.
The problem with doing that is the set screw would be bearing against the finished surface of the spindle. As most socket setscrews are alloy and through-hardened, the screw would eventually divot the spindle.

What I am going to do after I face the backing plate and size the chuck register is drill and ream extra holes to accept dowel pins. The dowels will protrude from the backing plate on the opposite side from the chuck face, giving me the means to use a "persuader" bar to tighten the assembly with much greater force than would be possible with spinning it on by hand.
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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Steggy
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Re: NEWLY-ACQUIRED JET 1236PS

Post by Steggy »

Bill Shields wrote: Thu Sep 03, 2020 6:09 amBut....they are cheap to make with local talent and materials...and what do they care about power consumption.

Besides the big motor helps keep the belt tension up.
Not only that, the big, heavy motor keeps the lathe from slithering around on the floor. :D
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Music isn’t at all difficult.  All you gotta do is play the right notes at the right time!  :D
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ctwo
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Re: NEWLY-ACQUIRED JET 1236PS

Post by ctwo »

BigDumbDinosaur wrote: Thu Sep 03, 2020 12:00 pm
ctwo wrote: Thu Sep 03, 2020 10:52 amAnd you might consider cross drilling the chuck backing plate and thread for a set screw to stop it from unscrewing - of course using a copper plug or something on the spindle thread.
The problem with doing that is the set screw would be bearing against the finished surface of the spindle. As most socket setscrews are alloy and through-hardened, the screw would eventually divot the spindle.
What I have seen is the screw would bear against the spindle thread, but a softer metal 'pad' is inserted first. I've also seen a hardwood dowel or a Delrin pad used.
Standards are so important that everyone must have their own...
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liveaboard
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Re: NEWLY-ACQUIRED JET 1236PS

Post by liveaboard »

My spindle has a shallow hole where the nose of the set screw goes. It's drilled into the smooth shoulder, not the threaded area.
I drilled holes in the backplates of later chucks I bought, but I haven't bothered with the set screw yet.
If the chuck is screwed tight, it seems to stay even with a lot of reversing, but I haven't cut anything serious in reverse.
Just backing up during thread cutting, and some polishing.
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