New To Me, Jet 1336pbd - With Some "issues"

Steve Shannon

Steve Shannon

Rocketgeek
H-M Supporter Gold Member
Joined
Nov 27, 2015
Messages
603
A couple weeks ago I found a Jet 1336PBD on Craigslist. I went and saw it and apparently my eagerness to have something big and heavy clouded my brain. It has some problems, which probably should have scared me away. They are (so far):
  1. One broken tooth on the bull gear,
  2. One broken tooth on the pinion on the back gear which meshes with the bull,
  3. Scoring and burrs inside the spindle (MT5),
  4. Lack of fastidiousness; the lathe is filthy, but the ways don't "look" badly worn,
  5. Quick change gear selectors would not move,
  6. One of the cap screws holding the headstock casting to the bed has broken; the head was just sitting in the hole, and
  7. One of the belt pulleys is broken.
Bit by bit I'm going to begin cleaning up the parts and try to find replacements for for the broken ones. If I determine that parts from a specific model of another company's lathe are compatible I will document that. I'm not disciplined enough to do a full rebuild thread, but I will try to post pics once I begin. That won't be until the spring though as I have way too many other things which I must finish first.
I'm interested in your comments.
 
Hi Steve, Welcome to the group! It sounds like you will need to apply some TLC to your newly acquired lathe. You will undoubtedly find someone who has gone through the same problems before you. Don't be afraid to ask. Whether it be a source of parts or suggestions as to how to tackle a certain tasks.

Bob
 
Thanks, Bob. I appreciate the encouragement. I've been poring through other posts in hopes of learning of parts sources. One general question I would ask is for suggestions regarding go-no go decisions and what order to approach the rebuild. I'm not looking to make this into a machine that will cut tenths and earn money with, just something I can use to play with.



Steve Shannon, P.E.
 
Hi Steve,

Welcome to the site!

It sounds like your expectations are set correctly. You know this lathe is a "project" now, but after hundreds of invested hours can be a usable lathe.
You are going to learn so much about that lathe as you proceed. You will know it inside out.

-broken gear teeth can be brazed then filed to recreate the tooth profile
-the bigger question is how they broke
-was it at the same time as the headstock bolt and the pulley? some sudden stop?
-was the lathe dropped? (yikes!)
-what other damage may be lurking?

Please note that NONE of this is meant to discourage you. With slow persistence you can return this abused equipment into a wonderful useful tool!
Do your research, ask lots of questions, and as my Dad has always told me 'do NOT make any big decisions at the end of the day when you are tired/sore/beaten/dejected'.

-light scoring inside the Morse taper can be dealt with by light stoning of the high-spots
-a nice, clean MT5 shank can be blued and used as a gauge to see mating spots
-a MT reamer can deal with heavier scoring (a little expensive for "one time" use, but you may be able to borrow one here.)

-a good cleaning is definitely in order

One other thought.....hit it NOW with some penetrating oil! Shoot every bolt, nut, thread, dovetail, half-nut, sliding gear, etc. Try to do it every 2-3 weeks and by spring you'll be amazed at how easy it is to work on. A 50/50 mix of ATF (Automatic Transmission Fluid) and acetone is my favourite. The mixture is so thin that it wicks into every crevice, the acetone does evaporate quickly but it leaves the oil behind.

Good Luck!
-brino

btw: please post some pictures when you can....even the dirty, broken "before" pictures.
 
brino,
Thanks for the good words; your list of questions is the same as mine. To me it looks like whatever broke the gears was a different event than that which broke the pulley. I do wonder if the lathe was dropped. I think I should check for spindle damage before I invest a whole bunch of money, but my time is cheap . I didn't see visible runout when the seller showed it to me. I think my next step is to pick up a Mitutoyo DTI and do some basic tests.
Is this the right forum to document my steps and mis-steps?
I've been shooting WD-40 in every crevice. I may just try your penetrating oil recipe. I interned in a ceramic engineering company and developed a very healthy distrust of acetone except for use in very small quantities. One splash in your eyes and your corneas are permanently cloudy. Of course I will wear safety glasses as I work on this.
The qc gear levers now slide easily along their shat, but only if I push right next to the shaft. Any force at the end of the lever and it sticks. I suspect wear allows the levers to cock slightly and bind. Does that sound reasonable?



Steve Shannon, P.E.
(Edited to correct auto-correct respelling of "brino".
 
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The Jet BDB-1340, looks very similar. Does anyone know if any of the gears are compatible?


Steve Shannon, P.E.
 
For example, the bull gear for the 1336PBD has the same module pitch and number of teeth as the one for the BDB1340. Same for the back gears. The two gears there have the same pitch (MP2) and number of teeth. The drawings, while not exactly the same, follow exactly the same layout, right down to the number in the picture. Now, I know that in 28 years and moving the manufacturing from Taiwan to China there could be insurmountable differences, but I'm encouraged by the similarities. If anyone on this forum has a BDB-1340, I would appreciate exchanging dimensions.


Steve Shannon, P.E.
 
Great! Could you tell me the length of the back gears, which is part #04109A. Just a close approximation would be a good start. If it's close to the length of the similar part on my 1336PBD, I might order one from Jet if they allow returns. No hurry, please, I won't order anything until late January.
Thank you very much!


Steve Shannon, P.E.
 
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In measuring my clone at home I have approximately 4.9" OAL. When I get to work next week I can measure the Jet BDB-1340 and post that one.

back gear.jpg
 
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