SB 10L help

mtlhe · Aug 17, 2004

Hello, nw to forum&lathes. Just bought a SB10L. It has the orig.switch that designates forward & reverse. However, reverse doesn't work. It was setup to run on 240v.Orig.wiring diagram shows a 3ph. motor.Orig.paperwork indicates this was shipped w/o a motor from SB.Q:Can a single phase motor run in reverse?If not, is this a big deal? Also, it has a leather belt which is in need of replacing. Is there any dealers that offer a never composite version that isn't difficult to install? Thank you

Webb Wyman · Aug 17, 2004

Hi There,

Yes, they can. But some 1 PH. motors do not provide the leads needed for reversing. But the need for reversing the lathe is not "generally" needed for most types of machining but it does come in handy at times.

To find out if your motor has the capability to be reversed (most can), you will need to check the wiring diagram either on the data plate on the motor or under the cover plate that accesses the wiring.

If you wish to persue this, you can email me.

Good Luck!
-Blue Chips-
Webb

kgregg · Aug 18, 2004

I'm an utter newbie so take my response with a grain of salt, but I just recently got a 10L in the exact same condition - it was shipped as a 3 phase with reverse switch and is currently wired 220 single phase and the reverse doesnt work. I was under the impression that the reason for this was because it had a threaded spindle and the sudden reversal could cause the chuck to unspin itself....

-Kevin

Webb Wyman · Aug 19, 2004

Hi Kevin,

What you say is correct BUT the vast majority of single phase motors are not Instant reversing motors. What I mean is, the motor must slow down before throwing the drum switch into reverse to get it to actually reverse the motor. If you throw the switch to reverse before letting the motor slow down, the motor will continue to run forward. This isn't true for 3 phase motors though.

-Blue Chips-
Webb

ztarum · Aug 19, 2004

My 10L came with a 3 phase motor. I converted it to single phase 240V when I got it and wired the switch so I could run the motor both ways.

So far I have never had the need to run it in reverse. If I were you I wouldn't bother doing the wiring job until I finally came to a situation where I really need the reverse.

It's not that the wiring job is impossible, but there is a lot more to it than wiring up a light switch, and it can be confusing. Plus you will have to run extra wire through all the conduit to the switch. I think it takes 6 wires to the switch to make it all go IIRC.

mtlhe · Aug 21, 2004

Thanks for the reply guys. I still need info on what type of belt I should put on this unit. I have been hours on the net trying to educate myself on the best belt. South bend offrs their glue together version for $100.00. A bit steep. Please advise. Thanks, Keith

JRouche · Aug 21, 2004

Reverse has been useful for me. I use it when polishing up a shaft with paper or cloth. I will prolly get yelled at about this, sometimes I wanna wrap my fingers around the shaft with paper under my hand. I can feel the metal and there is more control VS grabbing each end of the abrasive and applying tension. I have found the only way to do this without wrappin yer fingers up is to reverse the spindle rotation. Just my way. JR.

Greg Menke · Aug 22, 2004

The 3 step pulley on a 10L takes a 1 1/4" wide belt, length between 40" and 46". McMasters has belts & alligator clips to join the ends- but that approach tends to make a bit of noise as the clips pass over the pulleys. Next time I'd go for one of the glued belt joints.

I got a composite belt from McMasters- smooth leather on one side with a nylon core. Works great! When you set it up, give the pulleys a good cleaning, they should be clean, dry & smooth. The belt doesn't have to be really tight when the tensioner is applied, just nice & snug.

Gregm

mtlhe · Aug 23, 2004

Thanks Greg, have you ever done a glue up methood? Dont you need sometype of tool w/heat for this process? Sounds like a pain.Is it? THnks

Greg Menke · Aug 23, 2004

Nope, I've not done it, but I've heard it produces good results. I think the glue is some kind of contact cement. AFAIK, the idea is the ends of the belt has the plies open for a few inches, you apply the cement (after you put the belt in the machine... heh...), then clamp the plies together till the glue sets. The upshot is you can't use just any belt, it has to be made particularly for glueing. OTOH, the old string lacing approach would probably be quieter than the metal clamps- no need for glue and you can use whatever belt you like.

Jon_Spear · Aug 26, 2004

Regarding the reverse direction:

If you use a collet closer, then you can safely run the spindle in reverse without worrying about the chuck falling off.

Some people prefer to cut screw threads in reverse, because they don't end oup running the tool into the headstock. For this to work with a regular (right hand) thread, you have to put the toolholder at the back of the compound slide, and upside down.

-Jon

kgregg · Aug 26, 2004

On that same topic, this may be a dumb question, but how do you stop the carriage when you are cutting threads?

I have only done it on my Taig using a little CNC controller so I could say, cut for 1" and stop.... not sure how I will accomplish this once I finish fixing up the south bend.

-Kevin

plbenoit · Aug 26, 2004

Kevin,
You pull up on the half nut handle. You have to push it down to engage, up to disengage.
Paul

kgregg · Aug 27, 2004

Ah, so you just watch it and disengage at the same spot each time. I guess that makes sense - its spinning pretty slowly with the back gears engaged.

I guess I was just thinking of the taig. The slowest spindle speed is about 500 RPM and the cutter travels pretty fast at that speed.

thanks,
Kevin

jim rozen · Aug 27, 2004

On the southbend lathes I'm used to, the half
nut lever is engaged when up.

I think he was asking about the best way
to deal with the end of thread problem though.
Best way is to leave a runout groove so you
can just disenage the halfnuts and let the work
spin with the tool in the groove.

Another way is to simultaneously disengage the
halfnuts and wind out the crossfeed screw at
a preset place on the work. For this a dial
indicator setup on the carriage is the way to go.
Likewise for ID threading inside a blind hole.

If the halfnuts have to stay engaged, then it
becomes imperative to have an instant reverse
motor, like true 3 phase ones. Then one simply
waits till the dial gage reads zero, and then
reverse the motor and unwind the crossfeed at
the same time.

This is not for the faint of heart, and I've
buggered more than one part, typically during
the *last* cut! (just one more....)

Jim

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