Stripped piston? Speed control

[IanT]

Hey everyone, so I am in the process of trying to refurbish this shopsmith it's a v v, i have it partially taken apart and it looks like the reason that the speed control knob was having trouble was because the shaft that the Allen screws into seems to be partially stripped, if I were to round out the hole a little bit with a Dremel would it cause any problems?

See photos. https://drive.google.com/folderview?id= ... UX4cdEjBLZ

The issue that I was having was that when I turn the machine on it would slow down and then Papa breaker or freeze and pop a breaker, I see that the motor seems to be spinning freely so now I am just diagnosing backwards

[rpd]

One problem I see is that the clip on the end of the control sheave should go on the outside of the flat spring on the quadrant, not between the spring and the arm as it is in the picture.

20200330_111203.jpg (780.18 KiB) Viewed 10236 times

[chapmanruss]

Before worrying about getting the clip on the quadrant as Ron noted above it may be best to remove the speed control assembly from the headstock for inspection. Checking the gears may reveal problems beginning like wear on the teeth.

You said

i have it partially taken apart and it looks like the reason that the speed control knob was having trouble was because the shaft that the Allen screws into seems to be partially stripped,

Is this the shaft you are referring to? See picture with arrow pointing to it below.

speed control - arrow.jpg (172.04 KiB) Viewed 10208 times

If it is and the gear behind it is okay than cleaning up the burrs would be okay but do not change the diameter of the shaft to avoid creating a new problem. Get back to us as we are happy to help you through any problems.

You can post the pictures directly on this thread as Ron and I have, just follow the directions in the thread linked below from Community on How to Post a Picture.

https://www.shopsmith.com/ss_forum/comm ... 19246.html

[IanT]

Yes that was the part I was referring to, so I was able to read machine that part, and I didn't see that some of the speed control teeth on the inside are bent or warped where the bolt goes in and the clip attaches, I was able to refile them straight and or bend them back together yeah, but I think that I need a new part. Aside from that my main issue is I can get the unit in the center to spin when I turn it on when it's on the highest setting, however if I add the bandsaw or anything else it slows down and then throws a breaker. I am not sure what is wrong with it as I am not familiar with this machine and its entirety, I spent the entire day watching videos about the speed control unit today. So I'm a little bit sad that I couldn't get it working after all of the modifications I did on it today. I just want to be able to use it already! The guy I bought it from sold it to me for $400, and it has a bunch of the upgrade attachments

[JPG]

You may have already looked at the teeth on the quadrant gear(porkchop) but it is those teeth that may be compromised. If the shaft turns fairly easily they should be ok(with the control sheave disconnected). The worm gear is not likely to be damaged unless the shaft is bent.

sp control.jpg (132.17 KiB) Viewed 10192 times

[IanT]

It does look like those keys were the ones that were compromised I filed them straight or bent them as well as I could, however when I read assembled it was still slowing down and stopping,

[DLB]

Speed Control - If it were me, I'd be concerned about gunk on the Motor and Idler Shafts impacting what should be the very free movement of the Floating and Control Sheaves. The visible damage to the shaft and damage you've described on the Quadrant, aka Porkchop, is frequently due to excessive force applied. If the Headstock hasn't been well and recently maintained, it is best to strip these shafts down and clean them, then oil as normal. This is almost certainly unrelated to a Circuit Breaker tripping.

Circuit Breaker (CB) - How many amps is it marked as? Does anything else turn off when it pops? A 1-1/8 HP Shopsmith draws around 13.5 Amps max according to the label. The motor, by itself with no belt and no load draws around 9.5 Amps. So if it is on a 15 Amp CB there is not a lot of capacity for other loads. Ideally the SS would be the only thing on a circuit while it is being used. If anything else is shutting off when the CB trips I'd first try to get the SS on a CB by itself. Do you have ability to measure AC Current to the SS? IF the SS is drawing excessive current, especially while not making sawdust, the most likely cause is the motor. Other possible contributors are a bad bearing, belt binding, upper belt too tight, etc. Basically something making the motor work harder than normal. If that were the case then that part would probably be getting warm or hot depending on how long you can run.

One possible cause of high current in the motor is the start windings not de-energizing when the motor reaches speed. You should hear a click in the motor when you shut it off as it slows down. This is easiest to hear with the belt off.

- David

[br549]

Your other new thread about slowing only when something is attached seems to be another aspect this thread, and both should really be combined. Until someone posts a reply to your second more recent thread, you still have time to delete it.

This topic in general really belongs in the Maintenance and Repair Forum, but nonetheless, here we are and I'll offer my meager suggestions.

You mentioned high speed. You should be trying to start with speed control set as close to SLOW as possible. With the power off, use a sanding disc or a lathe faceplate attached to the quill and slowly manually turn it while turning the speed control to SLOW.

For a better understanding of how everything should work, the first three threads in the Maintenance and Repair Forum (called "stickies" because they always stay near the top) offer a wealth of info on what to look for in a used machine, how to rebuild certain parts, etc.

[JPG]

The tripping circuit breaker had me stumped also. Indeed if not on a dedicated branch(or nearly so) circuit and a 15A breaker will explain it. Also the start switch not opening the start circuit is also a possible cause. An extension cord is also a gremlin.

Re the sanding disk, do not leave it on when attempting to start it. The steel disk adds considerable inertia to overcome when starting.