Pipescs wrote:the indicator ring or mount is also bent causing a binding as you turn the handle.. While it works it is distracting
It looks like a piece of round bar, turned down and bored, hexed, with a threaded area. Probably a bearing or bushing on the inside which possibly isn't hurt.
You could probably make a new one in less time than you will waste hunting for one, and gain a bit more experience in doing so!
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
South Bend tachometer drive gear PT8718TT2. I have a 1971 SB 14" lathe similar to yours that needs a replacement for this gear and/or design specifications for said gear. Currently this part is obsolete and not in stock. I saw from your photos of your unit that you still have this gear. Could you send me a sketch with the dimensions and number of teeth of your gear? My e-mail is dmaradei@controls.com. Thank you for your assistance.
Dmaradei, I also have a SB Fourteen, same vintage as Charlie’s. If the SB tach gear you ask about is the small fiber gear mounted down near the floor, under the lathe bed, you can probably order one off eBay. I bought one last year, searching via google. Don’t spend any time trying to contact South Bend. They are long gone- parts for current machines only carried now by Grizzly.
Cheers,
Glenn
Moderator - Grand Scale Forum
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
I’ve found this thread a wealth of knowledge in going through my lathe and have added a digital tach and gotten the oil pump working. The belt was a bit beat so I had ordered a new one according to the existing but I don’t get the specified rpm range. The belt that came equipped on the lathe is a 2322v421 and I was curious as to what others have. It seems as though mine may be too large in diameter or too narrow. Having had other machines with this type of drive I question having the proper belt. My serial number indicates it being the early version.
Charlie, are you still following this thread? Or, for anyone with a SB Fourteen, I am curious what max depth of cut You can reliably take on your machine before it stalls?
Today, I was only able to cut about .060” per pass, when taking down some 1.5” round stock. Anything heavier and the lathe basically stalled out and came to a stop. I’ve never really used this machine for heavy stock reduction before, as my old Standard Modern 12” lathe would take off 1/4” with each pass. But I sold that machine a while ago, intending to use the SB fourteen for most of my work.
60 thou seems like a pretty light cut after routinely hogging off .200” to 250” during each pass.
Thanks
Glenn
Moderator - Grand Scale Forum
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Glenn Brooks wrote: ↑Thu Oct 25, 2018 11:23 pm
Today, I was only able to cut about .060” per pass, when taking down some 1.5” round stock. Anything heavier and the lathe basically stalled out and came to a stop.
What stopped? Did belt(s) slip, or did the motor stop?
60 thou seems like a pretty light cut after routinely hogging off .200” to 250” during each pass.
I agree. You need to determine why. If you have a small motor (one horse or less), it's likely underpowered. If it has a flat belt, that may also be part of the problem.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
This is just one of many places where you can get a crank handle of any size and shape. Really no reason to make one as they are very time consuming to make as a matchup. https://www.mcmaster.com/hand-wheels
Today, I was only able to cut about .060” per pass, when taking down some 1.5” round stock
Rpm and if you were in high or low would help. I noticed that as I’m going through mine the belt was pretty well beat. I replaced it and in low I had a speed range from 40 to 100rpm +- and in high it was like 200-900rpm +-. At the low speeds in high or low the drive pulley would open too far putting too much slack on the belt. I could actually stop the chuck with my hand. After setting the speed to 50rpm the belt looked much better as far as tension. I then set the limit stop at that point. With the new belt it would ramp up to 1000rpm +-. Looking at the ulley guide slot it is worn to where it will bind and won’t let the pulley close to a larger diameter. I removed the guide and belt then operated the screw assembly by hand till it stopped to see where it’s limit is. It actually goes beyond the wear spot. I’ll grind the slot reassemble and set the limits when I get the desired high rpm. I also confirmed the 2322v421 belt.
I experimented some more with depth of cut. Found I had set my feed rate way to high - just under .040- hence couldn’t take a DOC over .060”. Lowering the feed rate to around .007” -.009” I could easily make DOC at .250”. The machine didn’t lug down or strain at all.
Also, you’ve got the right belt. I checked mine today and it has the same part number as yours. Mine is new as of last year. The Gates rep says these style belts are very very common in industry- they use them all over the place for automated flat belt package and parts distribution on assembly line style belt drives in warehouses.
Two tips for setting speed: I can’t remember exactly, but either the little fiber speed control bearing, mounted on the floor, next to the lower VS Vee pulley, or the lower pulley itself, can be manually adjusted in and out to set speed ranges. This changes the min and max speed ranges of the VS pulley unit. It sounds like your speeds are set to low. Perhaps if you experimented with the turning the stops out, you could ideally set low gear to top out at around 400 -500 RPM. With High range over 1800. Lowest speed would be around 50 RPM, or the belt goes loose, as you said. Iam going from memory, but when I replaced my V belt 18 months ago, I found I could vary the speed range quite a bit by moving the threaded rod that holds the little 1” diameter speed control - or maybe it was the lower pulley... but fairly simple thing to do.
Second thing, these V belts get stiff and oblong when sitting in place to long. They adopt the shape of the pulley system. When this happens they make a loud thumping sound until they loosen up and loose their egg shape. A squirt of belt dressing helps them become more free flowing again. When they get to old, the thumping sound gets louder and louder, like bearing noise. Just means it’s replacement time.
Good luck on your machine!
Glenn
Moderator - Grand Scale Forum
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....