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13" SBL Gear Box Adjustment

Canyonman

Hot Rolled
Joined
Dec 28, 2004
Location
Oklahoma
Hi, Been lurking your forum awhile, reading the archives, and HTRAL. Will try not to waste your time. My problem is on the 13" TKL 10 with a 7' bed, double tumbler gearbox. Machine is nice and tight/quiet with reverser in neutral, normal or backgear.

Two "noises" beyond that.

1. Place reverser into either position and machine gets noisey. #27 twin gears (HTRAL Nomenclature) are almost knife sharp although not bottomed out. Maybe worn almost to the "slipping" stage. Engage gearbox, no problems.


2. Place into backgear, reverser noise diminishes, however, engage the gearbox and the idler gear is silent for 3/4 of a rev then, "shudder,shudder,shudder," <sound and gear train> and gearbox jumps. Found two <nearest the gears> of the gearbox mounting screws loose. Tightened them, repeated ops, gear train seemed to bind even more, and more noise.


Add'l Info, at this point I have re-loosened the screws. With screws tight the "square nut" adjustment to the right of the gearbox is set in pretty far, beyond half, and gearbox seemed crooked <to the eye> Have not even started to clean the motor pedestle, V-belts worn and loose, and the leather flat belt is stretched and slips some. I figured that might be a good thing till I become more familiar with this lathe.

3. Lastly, a more knowledgable person advised me with this purchase, He said I needed something as when you grab the toolpost it will "chunk, chunk" about a quarter of an inch. What part would that be?

She is cleaning up nicely and should make a fine lathe when I make her well.

Questions, thoughts, opinions, advise, all welcome. Ken

PS Gotta love those sound effects!!
:D
 
I just wondered how you made out with your lathe. First, I would recommend you get a copy of the South Bend Parts manual. You can buy them from Leblond, or get one on Ebay, or you can find parts of the manual on the web. Secondly, I am curious, were you testing the lathe under power when you were having these problems? Or were you turning it over by hand? I would recommend turning it over by hand and observing the gears to see what is binding up. On the double lever gearbox, the bottom is open, and if you sit on the floor with a flashlight, you can see right up into the gearbox and observe most of the gears. I notice on your other post that you were looking to buy the gears on the feed reverse lever. Did you do that? If so, how did it work out?

I assume you have observed all the gears that are visible on the end of the machine and don’t see any other problems. That only leaves one of the gears in the gearbox. It is possible that there is a piece of trash in there, or that a tooth is broken off, usually caused by someone trying to engage the box while the machine is running. My personal habit is to turn the machine over by hand at least a little to make sure everything is meshing correctly each time I make a change, (this includes feed reverse, back gear, quick change gearbox, ;and the apron controls) before powering up. I think it is a good way to prevent mistakes, particularly when you are a beginner.

Whether the backgear is engaged or not shouldn’t really make a difference as far as the quick change gearbox is concerned. If you find the gearbox is damaged, you might be able to buy a new gearbox from someone who is parting out a lathe.

As far as the toolpost movement, both the compound slide and the cross slide run on dovetailed ways, and are held tight by a tapered gib that can be taken up with an adjusting screw to allow for wear. It sounds like one of these gibs is missing, but that is just a guess, based on what you have told us. Again, once you get a parts manual, you should be able to figure out what is missing. Don’t be afraid to ask more questions, someone is bound to answer sooner or later.
 
Sounds to me like the gears are dirty with chips packed in between the teeth in random areas.

Scrape out all the caked oil and chips between EACH tooth and clean each gear thoroughly in solvent.

Jim C.
 
Hi Guys!

Thank you for the replies, I thought my inquiry was dead!

I now have access to the O & M and Parts manual. Not sure it is a "legal" copy but personal use only Blah Blah. Kris, yes the lathe was under power, in back gear @ 4 TPI, locals say I was asking it to do something out of its' capabilities, makes some sense. Also Jim, I cleaned the gearbox, (without disassembly for the present) with brake cleaner as suggested from other "lurkings". Inspected and re-lubed. All gears, teeth, engagements, etc. are clean, square and good.
Kris, I ordered and recieved the reverser gears, that is the next project, got sidetracked, picked up a used industrial MIG welder cheap and spent this weekend/paycheck (read SWMBO allowance!) Getting it up and running. I also had to replace the flatbelt, made a new one and could not bring myself to put it into that crusty headstock. So I have been cleaning the headstock and UMD area ( Will paint next winter, primer for now). Made a 1" belt for two reasons, only stuff my friend had and I was advisd 1" belt would be more forgiving of rookie mistrakes. Can go back to 1 1/2" later.
Some are afraid my leadscrew may have been bent in the move. Can't check that yet cause I can't get the screws loose to lift the saddle.

Toolpost movement cured with new crossfeed and compound nuts from Miller Machine, reasonable price and excellent workmanship too, I thought (shameless plug!). Gibs were all there and in good shape although I think someone tried to solve the toolpost problem by tightening them up some.

As for answers sooner or later, I truly appreciate both of your replies. I had a tiff with the moderator and his friends early in my forum participation and although I apologized, and questioned, and been told I'm just getting paranoid, I seem to have been unofficially blacklisted, as noted by the number of replies whenever I post. So sorry for the long winded post, but I read more and talk less now.

Once again Thank You and hope to hear from you again. Ken
 
Canyonman:

Did you also clean the gears in the train between the spindle and the QC ? They are the ones most likely to pick up chips from boring that have made their way through the spindle bore. This can be prevented by plugging the bore at the back end. I use plastic "Caplugs" but a small wad of paper stuffed in will also work.

Jim C.
 








 
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