# Power feed for South Bend 9 inch



## Shipdisturber (May 18, 2017)

I would like to get away from the gear set for my South Bend 9 inch and would like a better way to power my feed screw. I was thinking of a belt system to run of the existing motor or a stepper motor system to power the screw. Any suggestions?


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## Niels Abildgaard (May 18, 2017)

Sure(Aber sicher):

https://www.rocketronics.de/produkt/els-pcb/?v=dd65ef9a5579


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## Shipdisturber (May 18, 2017)

That's great Niels now all I have to do is translate it. Thank You


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## Wizard69 (May 19, 2017)

Shipdisturber said:


> That's great Niels now all I have to do is translate it. Thank You




Look up "electronic Leadscrew".  For some reason i believe there are two different solutions floating about the net and on English.   The other option would be to implement a CNC controller solution like GRBL and just have it run one axis.   .  

By the way GRBL isn't exactly the best choice for lathe work as it doesn't spindle sync yet.  However if your goal is to feed the saddle at a selected rate it can do the job.  You just cant sync the spindle for threading for example.  

The good thing with GTBL is that you are have way there to a CNC system if you should decide to go that route in the future.


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## Niels Abildgaard (May 19, 2017)

Shipdisturber said:


> That's great Niels now all I have to do is translate it. Thank You



You are welcome.I sometime forget being danish means that our school system has spent a lot of effort on language training.You are not much worse of than me:
I do not hear very well but  his videos are quite informative without sound.
The Guy, making rockets as pastime,might be able to understand and answer in english.


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## Shipdisturber (May 19, 2017)

Thanks guys I appreciate the help. Niels I have a translator on my computer so what you posted will work for me. Wizard, indexing never dawned on me. The other problem is teaching this old dog new computer skills is it basically as fun as pulling teeth for me. I have an arduino board put a friend in England programs it for me I'm more suited to things mechanical.


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## petertha (May 19, 2017)

I'm not familiar with your SB-9 lathe but going through some power feed grief on my 1998 Taiwan 14x40 right now, mostly chasing down rapidly diminishing parts availability. My power feed bar is 19mm OD x 5mm wide keyway slot. (A separate function altogether from the threading rod which is engaged with typical clam shells). 

The headstock gear train drives the power shaft which drives a hardened steel worm engaged by a key which drives a funky profile tooth brass gear which displaces the carriage through the apron gears. Its taken me a while to zero in on the problem but right now looks like I have a slightly bowed shaft and wear to the CI bracket & brass gear. I (briefly) looked at motorized solutions but came to the conclusion they are way above my head & would be a substantial modification. The other consideration is there some significant amount of power being transmitted & the gears provide a lot of mechanical advantage as evidenced by manual mode rack & pinion carriage traversing. So a solution mightrequire careful consideration of where the motor is positioned, cut load demands etc. Good luck & keep us posted if you build something


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## Niels Abildgaard (May 20, 2017)

If steelshaft inside the brass nut rotates,it is very close to the SB/Boxford arrangement.
An australian (FOURBOLTS where are You now?) removed the worm and drove the steelshaft/brasswheel combination with a small electric motor with a lot of reduction and a dc controler .Very very neat solution but for the life of me I cannot find the picture.Only problem is if spindle suddenly stops the external feed power must be cut very fast.


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## petertha (May 20, 2017)

Niels Abildgaard said:


> Only problem is if spindle suddenly stops the external feed power must be cut very fast.


 
Good point. 

Another complication, at least on my lathe style, is a 3-position shift lever that engages longitudinal feed, neutral & cross feed. In either feed mode a mechanism behind the apron gear box prevents the threading lever from closing. I'm sure some lathes could be motorized but more than I'd ever want to tackle on this particular one.


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## Shipdisturber (May 20, 2017)

This is all looking very in depth. Based on what I really want to do is be able to change the feed speed adding an electronics system to me seems more ambitious than what I'm after. Pulleys are too hard to time to my cuts I think so that leads me back to gears. I would actually like plastic gears thicker than what I have but with more of a selection for speeds. The reason I want plastic is they will be the first thing to break in case I mess up or fall asleep at the switch (just kidding). I don't know where I can get gears for my lathe without paying a bundle. If I go plastic I can actually adapt them to my lathe no matter what the teeth per inch are, where can I get plastic gears at a good price?


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