Need correct reversing drum switch for SB 9A

finsruskw

finsruskw

H-M Supporter - Gold Member
H-M Supporter Gold Member
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Sep 22, 2019
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Can someone steer me towards the correct reversing drum switch for my SB 9A w/3/4 hp reversing motor? There is no switch at present only a cord coming from the motor with a plug. I did manage to reverse the wiring in the motor case to get it to turn the correct way. I really would like to get this sorted out with the correct switch to avoid having to reach across the machine to plug it into an outlet all the time.
 
Can you post the nameplate info from your motor that shows the high and low voltage configurations. That will help us help you get it connected properly
-Mark
 
I scoured the internet for a couple of days before I found the correct diagram. Read article after article talking about start windings etc. I assumed L1 was the black/hot, and later learned that in fact it wasn’t. L1 is the White wire. Green of course is ground and L2 is the Black Wire. The catch is (or at least was with mine) that you have to put a jumper wire from one side of the switch to the other, and you’ll see that in the diagrams and explanations. The various drum switches are marginally different but the concepts are the same. However, and to be clear, I AM NOT AN ELECTRICIAN so take what I’m saying with as nothing more than “2nd hand info”. With that said these switches most times have a wiring diagram on the inside of the housing, have you checked there? I’m just up at my cottage or I’d copy the notes I made and forward them to you. A bit of reading though and you should be fine.

Cheers

Derek

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3/4 x 1 HP
Reversible
110-220
1725 rpm

I was told to get one rated for more than what the motor is and also one w/replaceable contacts.
 
Sorry..... I misread initial post. I thought you had the switch and were trying to sort out the wiring. A good “Furnas” (brand name) switch will work. Replaceable points is I guess nice but in all the years I’ve been at this I have never seen a lathe used so much that the drum switch points were worn out.... I suppose it could happen. As for rating, grab one that will handle the next size hp over the motor you are using and never have to worry about it. Good luck though.


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When my dad started his shop his lathe was flat belt driven by a model t engine outside the shop. Every time he needed to measure the dia he would run out and shut the engine down and when done he run out and restart the engine. He would have been ecstatic to only have to unplug the cord. OK now to help you out, that should work. I found the Dayton kinda pricey and bought a Chinese one off e-bay took me a while how to wire it but it works a lot better than the original.
 
I can relate to that! Well...kinda!
Having trying to make some reducer type shafts and getting them all the same,
Am about to wear out the receptacle on the wall!!
 
Showed up on my doorstep just now!
Going to take some doing though to get it mounted INSIDE the cabinet and use the mount holes for the cover plate and not drill more holes in the cabinet proper.
The knob looks like it will hit the chip tray, will need to make an extension of some sort.

DSCN8039.JPG
 
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