1340 GT crash! ! !

RandallsRaceShop

RandallsRaceShop

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It is with a very heavy & shaken up heart that I have to make this post.

I was in the process of threading the top half of a machinist jack (3/8”X16).
All was going well & I was in rhythm. Stopped to check the thread & see how close I was to finished. I needed a few more thou, so back at it. Second pass in & I think I missed disengagement of the half nut.
Of course loud noise, I jumped back (involuntary reactions suck), instead of instantly smashing the e-stop. As quick as I could I hit the e-stop, but of course this is way too late.
So I take the nut off the top of the tool post, remove the bolts for the cross slide & get my tool holder out of the chuck jaws.
Re-installed the cross slide & mounted the tool post back up…,…,…time to see what the consequences of my mistake are.
I start the lathe back up, engage half nuts in the same gear I was already in (C-1). Everything runs but the gear makes a noise, maybe like a damaged tooth.
I stop the lathe, looking up inside of the gear box & I really don’t see anything.
I tried some other gears real quick & all other gears sound normal. Go back to C-1 & the noise is there, as expected.

I’m still kind of in shock/shook up that I’ve just crashed my new lathe. As a matter of fact, after it happened, I said out loud “Oh my god I just crashed my lathe!” My thoughts are still a little scattered.

QCGB is coming apart and/or coming out for sure, so I can get a good look at the damage & get it repaired.

Any advice on other stuff to check?
Spindle, bearings, carriage, etc, etc.?.?.?
Of course I’m thinking the worst at the moment. It would be nice if I just messed up a tooth on a gear, but I’m a little doubtful, seeing as how the entire lathe was all locked together to thread when this happened.

Thanks in advance
Randall.
 
It could be any gear in the train, I would start with the banjo gears under the belt guard, those are the easiest to get to, and are dependent on a screw holding them in place, so if you are lucky, could be those. If those are good, then look at the gears in the Norton gearbox, you can see them from underneath, might not need to disassemble anything. If those are good, next in line is the rack and the gear from the apron that drives it, and then inside the apron.

Fingers crossed it is a simple, and cheap fix.
 
Ischgl99 said:
It could be any gear in the train, I would start with the banjo gears under the belt guard, those are the easiest to get to, and are dependent on a screw holding them in place, so if you are lucky, could be those. If those are good, then look at the gears in the Norton gearbox, you can see them from underneath, might not need to disassemble anything. If those are good, next in line is the rack and the gear from the apron that drives it, and then inside the apron.

Fingers crossed it is a simple, and cheap fix.
Click to expand...
It’s most definitely in the qcgb. It’s gear #1 on the right hand side of the box (labeled as 1-8). I ran it in every other gear & everything is normal. Run it in #1 & I get the rotational noise.
I just cannot see the damage looking from underneath. I’m thinking at least get the front cover off of it, that way I can see what happened to it.
Thank you for the well wishes too, I appreciate it.

Randall
 
It happens- fortunately you have a brand that's well supported, although there may be a bit of a wait for the part
 
Oh man sorry to hear that. Happened to me years ago, fortunately, I just lost an insert and trashed the part I was making. Now I don't thread towards the chuck anymore. Anyway, it doesn't sound too bad, maybe a gear to replace but it could have been worse.
 
Eddyde said:
Oh man sorry to hear that. Happened to me years ago, fortunately, I just lost an insert and trashed the part I was making. Now I don't thread towards the chuck anymore. Anyway, it doesn't sound too bad, maybe a gear to replace but it could have been worse.
Click to expand...
Yeah, I’m going to the camp of upside down threading tool & lathe in reverse from now on. I really don’t want to experience this again.
 
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