Jet 1236P

All discussion about lathes including but not limited to: South Bend, Hardinge, Logan, Monarch, Clausing and other HSM lathes, including imports

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spro
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Re: Jet 1236P

Post by spro » Fri Jul 14, 2017 12:44 am

Well in a way, cutting LH Outside threads is easier because of starting from the shoulder and working backward. Then again, not everyone has tools ground or holders for that. This instant reverse biz has more to do with reading the thread dial and even there, there is more. Those particular Enco/Jets have this lever which jockeys the motor and releases the tension. It is on a cam. Mine is adjusted so that it will turn but not at the same speed or torque as fully engaged. I'm playing with the fact that it has a very wide belt, instead of two matched ones at that point. This doesn't disrupt the timing or anything further down the gear train. It does allow the spindle to turn very slowly and even start a cut while I increase the cam leverage.

spro
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Re: Jet 1236P

Post by spro » Fri Jul 14, 2017 1:01 am

A bit more. Thread dials. All so many wonderous lathes which built so much had threaded spindles. Most if not many, had 8 divisions or more... I stop there about dial divisions and lathe charts...it is so already there. What they didn't have was reverse at the apron. The machinist had to make a conscious decision to reverse the spindle of an 80lb chuck in order to run everything backwards.

spro
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Re: Jet 1236P

Post by spro » Mon Jul 17, 2017 4:51 pm

These Jet, Encos and many others were made by the same company in Taiwan. UK lathes lists the "Lantain" lathe brand. Many of the different brands and models are really Lantain. Lots of info / pics and they sell manuals for them.

jcarmon
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Re: Jet 1236P

Post by jcarmon » Tue Jul 18, 2017 9:22 pm

I solve the chuck install problem. It seems the chuck goes on in so precise a position, it has to be mounted DEAD center of the plate, and then once its pulled tight, it goes on and off with no problem. The more I learn about this lathe, the more things make sense. Its like this lathe has none of the normal wear that makes things go easier. Even after soda blasting it, all the corners are still sharp, like its right out of the mold, and grinding process. I'm starting to believe the guy that bought this thing new tried to learn to use it, and just gave up at some point. Left it sitting covered in dried grease for 40 years. I think the problem I'm having with the QCGB is because its never been shifted from the C gear range. It just set there running the whole time in the same range.

spro
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Re: Jet 1236P

Post by spro » Tue Jul 18, 2017 10:03 pm

I misspelled Lantaine. My chuck is original to the lathe also. The backing plate has the spiral thread marks of the deepest inside thread. It also fits very snugly. I think you have a good machine there. After all these years, there is some shop cred.

spro
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Re: Jet 1236P

Post by spro » Fri Jul 21, 2017 1:47 am

What I meant was the radial register. Part of the back plate of the chuck is usually unthreaded before it goes to the largest diameter of the nose threads. In these cases; they were ... heck probably ... they got it dang close and screwed the chuck on. Cain't say from here. Sometimes we get lucky. We know that over at P. M. they don't even discuss this "junk". There are reasons for that but as screwy as some of these were, some very good ones were made.

spro
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Re: Jet 1236P

Post by spro » Fri Jul 21, 2017 3:41 pm

NO, no, no! This wasn't forced. It was the very tip of sharp threading tool ! Very snug and needs to be started the same way from the collar of the backplate. It has been many years and I haven't been on any "Asian Lathes" sites to discuss or know this was common but there it is. I can imagine the collar being started in just the wrong position, causing binding or wear.

Elmojo
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Re: Jet 1236P

Post by Elmojo » Sun Apr 15, 2018 7:25 pm

Hi folks!
Sorry to dig up this older thread, but I have a 1236PS as well, and since you guys seem to understand this machine pretty thoroughly, I figured you might be able to help me out.
I can post my own thread if that would be better, but I'm a fan of keeping boards uncluttered and topics grouped.

Anyway, ever since I bought my lathe, it's always had a 'jump' in it when I used the power feed in a certain range.
I finally got around to opening up the QCGB the other day, and I see the reason why...one of the the gears is missing several teeth!
I feel like I could buy (or even make) a replacement gear, but I can't figure out how to remove the shaft that holds the gears. I see the end of the shaft on the right side, protruding through the side of the case, but nothing is obviously holding it in, other than a simple snap ring.
Anyone know how to disassemble the gear box, and also where I might find a replacement for that broken gear?
Thanks in advance for any advice or direction,
-Mike

John Evans
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Re: Jet 1236P

Post by John Evans » Mon Apr 16, 2018 6:20 pm

Replacement gear 1 try Jet 2 see if any of Grizzly's current offerings have a part that may work,lots of times you get lucky that way, 3 make or repair what you got. build up some braze and get to work with a file. A few pictures would help with tear down suggestions.
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ctwo
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Re: Jet 1236P

Post by ctwo » Mon Apr 16, 2018 8:30 pm

All of my QC gears are a bit pointy... Good advice John.
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Elmojo
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Re: Jet 1236P

Post by Elmojo » Tue Apr 17, 2018 1:53 pm

I feel fairly confident I could replace the gear...if I could figure out how to get to it. I figured you guys who have this lathe would maybe know how to get the gear train apart. I'll see if I can figure out how to transfer the photos from my phone to the computer. I also see that this forum has a rather odd size limit on photo dimensions, so I'll have to try to resize them as well. Let me work on that....

Harold_V
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Re: Jet 1236P

Post by Harold_V » Tue Apr 17, 2018 3:45 pm

Elmojo wrote:
Tue Apr 17, 2018 1:53 pm
I also see that this forum has a rather odd size limit on photo dimensions, so I'll have to try to resize them as well. Let me work on that....
The size limit isn't odd---it's just restricted to smaller sizes, all of which are conventional. Resizing should be nothing more than a simple click, selecting common pixel sizes.

The reason?

Some folks don't seem to understand that everyone isn't fortunate enough to have a high speed connection. As a result, they lose sight of the fact that those who aren't so fortunate have issues with images being downloaded, often not being able to at all when they are excessively large. In fact, I am one of them. While I have a DSL connection, it is badly overloaded and performs scarcely faster than the old dial-up I used to have. To add to that problem, those who might be fortunate enough to have an adequate connection then have to suffer the consequence of paging side to side to read posts in threads where overly large images are displayed. Every post on a page where such images are posted result in that problem.

Solution? Limit image size.
Benefit? All readers have an opportunity to see the images.
Bonus? Extended use of the hosting service, due to smaller overall file sizes. In most cases, large images serve no purpose, as much
smaller files sizes and pixel counts will display an adequate degree of clarity.

A win/win situation for everyone, as this board has been provided at no mandatory cost to readers (although donations are readily accepted, all of which go directly to support of the board).

Sometimes we are all guilty of thinking we are on this planet alone, that our actions, while beneficial to us on a personal level, may be interruptive of the activities of others. I know I'm guilty of that, although I do try to be considerate of others. A little "walking in the shoes of another" goes a long way toward building a better understanding.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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