South Bend reversing gear stuck

[Tim9]

Hello, The Southbend has to one of the best hobby machines. I really like the look of them. I haven't fine the right one yet. I mean I haven't found a (Cheep one) I think the heavy 10 is the way I would like to go. You have a beautiful machine. What a great job you did it differently has that look it's awsome. Happy machining.

Heavy 10 is much stouter if you have the space. Part of the beauty of SB 9 is how easy it is to move. It’s a light duty machine and no way as ridged as the Heavy 10, but it disassembles in a snap for moving. I’ve moved a few SB 9’s all by myself by taking them apart and splitting the lathe into smaller pieces. That’s a plus in my opinion. Hell,,,I can take a 9 apart in less than an hour. They are also the perfect first lathe due to their belt design. Just makes them a little less daunting if one were to be careless, belt slips before they twist ones arm around a rotating Chunk of metal. But, in most cases we all want a bigger and stouter machine like the Heavy ten once we graduate from the 9.
I found a Clausing 5900 series and I love it. It’s way more machine than the SB 9. But ain’t no way a easy move.

 

[joebiplane]

View attachment 308272

I love BLUE.... No matter what color it is @

 

[Bruce Billett]

I am restoring a South Bend 9 and work has stopped due to a stuck reversing gear. It loks like no maintenance was done since the machine was made in 1947. Everything but the final gear on the shaft has disassembled but that gear needs to be pressed off. A mechanic friend tried with his 20 ton press - dyidn't budge. I took it to a local machine shop and they stopped trying when the pressure was nearing a breaking point.
I have to get this apart. It drives the entire gearbox and screw. I can't afford for it to fail. Any ideas would be greatly appreciated.

OK So I just KNOW someone has suggested this, but have you tried heat? Also shock. And of course in combination? Another one is COLD!! You got any access to LN2? Drip it down on the inner shaft. Be REALLY careful with this stuff if you haven't played with it before! It's like 275 deg BELOW zero!! Drip it down on the center shaft until it gets REALLY cold. Then smack it with a hammer. That should then allow you press it out if it don't just down right fall out.
Do be careful this makes EVERYTHING brittle at these temperatures! DO NOT cup any into your hand! It is INSTANT frostbite!! Best to wear GOOD thermal glove! After treatment your skin will instantly stick to it!
Also do NOT try to put this in any sort of sealed container or carry inside your vehicle! Container will violently explode if sealed. It will also be very happy to displace oxygen in your vehicle! ( Bad thing ) Your Dr. may have some on hand for freezing off warts. He would also have the perfect applicator for the job.

Hope this helps.

b

 

[Asm109]

If you read all the responses from this year and a half old thread, you would see the solution turned out to be heat.

 

[Bruce Billett]

New to this, As a rule I don't do forums so not really familiar with protocalls and what not. Sorry about that.

 

[brino]

@Bruce Billett ,

No big deal, no apology required!
We are generally a friendly and tolerant bunch here.

Please don't let this sour you to posting, asking and contributing.

Welcome to the group!

-brino

 

[Bruce Billett]

Thank you. I shall not be dissuaded by this, perhaps the next though?
After all I'm guessing not many know about the LN2 trick. Not a lot of stuff laying around with LN2 in it.


b

 

[brino]

Agreed.
Liquid Nitrogen is not on the normal "go to" list for me.....but I'm always on the lookout for new techniques!

-brino

 

[Bruce Billett]

It is a bit of a speciality item. Really I only know about it because of my job.

b

 

[Ezra_Walker]

I am restoring a South Bend 9 and work has stopped due to a stuck reversing gear. It loks like no maintenance was done since the machine was made in 1947. Everything but the final gear on the shaft has disassembled but that gear needs to be pressed off. A mechanic friend tried with his 20 ton press - dyidn't budge. I took it to a local machine shop and they stopped trying when the pressure was nearing a breaking point.
I have to get this apart. It drives the entire gearbox and screw. I can't afford for it to fail. Any ideas would be greatly appreciated.

I’m sure that you’ve probably tried everything that I’m about to suggest..it sounds like you’ve got really smart and determined people looking at it...but..
just in case, here goes.. when I have a interference fit transmission gear stuck beyond all Hope I start by soaking the part in Evaporust. Rust can develop in near anaerobic environments causing an nanolayer of gritty oxidation which resists slip. once in the bath I put the entire container, parts and all into a large vacuum chamber and drop to neg. 40 atmospheres pressure. Holding it there for 2 hours should do the trick. As you reintroduce positive pressure connect the inflow valve to your inert welding gas and keep oxygen out. Once back to ambient pressure you can remove the part and attempt pressing the gear off. If that doesn’t work, I suggest a blend of oils that we use in our shop which is basically 50% Lard Oil (not bacon grease!), 45% Ultra-refined MCT Oil, and 5% Ultra-Refined White Mineral Oil. -and back into the vacuum chamber for 2 hours. Don’t bother with the inert gas depressurization, O2 won’t penetrate this oil. Again, try pressing it off. Now if it hasn’t budged at all, extreme problems call for extreme measures. I’m sure you tried freezing the shaft in liquid nitrogen for 1 hour then gently but rapidly warming the gear extremity with a focused rosebud at the same time as applying direct press pressure? If all else fails. Carefully tape off the shaft and gear in solid layers of masking tape leaving a 1/16th gap on both sides of the shaft/gear joint then submerging it in an electrolytic solution and connect the shaft as anode and a piece of raw iron as the cathode and allow it to de-bulk the area left exposed..(I did say this is an extreme measure and the shaft will need to be spray welded and re-machined if it works. This should remove material on either side of the gear in micron-layer levels which may facilitate removal of the gear. If rust still exists between the metal this method should pull it out within 12 hours. If you see visible material removal and the gear still is stuck STOP.
beyond this there are methods of restoring the gear teeth on the shaft. New spray welding technique gives very focused build up on the teeth and can match the gear material exactly. And if this is impossible give a shout-out to some of the better machinists on YouTube and ask what it would take to have a new shaft and gear machined for your lathe. I’m thinking of Adam Booth or Keith Rucker who have lots of experience with just this scenario and also restore lathes for themselves and others. Best of luck! I tend to deal with these issues pretty often while restoring 80 year old+ tractors and old logging mill transmissions and these methods have never left me ‘stuck’.