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Speed Control Broken?

EricJohn

I just bought a used 520 and everything was sticky. Been cleaning the unit with the Table saw bench on. Thus the warning sticker about not adjusting the speed without the motor running being ON TOP of the Power unit was impossible to see. The speed dial was difficult to turn and of course because everything else was sticky I forced it and heard a pop and something fall. Now the gearbox is locked.

Is this to become pile a scrap metal? I see how the motor drops down but the gearbox is up inside of the solid steel body. How can I possibly fix it? I am in LA. IS there any repair people here? Who's genius idea at shopsmith was it to put the warning label for such a critical piece of information up on top where it is impossible to see with any of the tables attached? You an see every other label except that one.

HELP!!!!!

edma194

It can all be fixed. The body is solid aluminum, not steel. On the backside of the headstock is a Shopsmith nameplate that covers an inspection hole. Yours may have a screw to loosen to rotate the nameplate, otherwise it is held in with spring clips. Maybe you could take a picture through that to see the speed changer from the back side. However, it sounds like you will have to remove the speed changer and replace one or more parts.

Use the following link to see headstock disassembly and cleaning instructions:

http://www.shopsmithacademy.com/SS_Archives/SS122/SS122_Common_files/Blackboard_images/Inspection_and_Cleaning.pdf

Here's a link to the headstock exploded diagram that will should match the part numbers in the instructions above:

https://www.shopsmith.com/service/headstock/headstock_diagram.htm

You'll find all the Shopsmith service parts and diagrams here:

https://www.shopsmith.com/service/mark/index.htm

There is plenty more documentation here on the forum.

Did you get a manual with your machine? I'm pretty sure it mentions the part about not adjusting the speed without the motor running. That is not likely to have caused your problem, I doubt that speed dial was going to move very much at all.

JPG

Which direction(towards fast or slow) were you making the adjustment when it cracked?

A pix taken through than access hole will be very helpful.

Fear not all is repairable.

chapmanruss

EricJohn,

First off welcome to the Shopsmith Forum. As Ed and JPG have said it can be fixed. The first thing is to find out what happened when you heard the "pop" and something fall. Ed has given you links to help you out. We can continue to help too. After this happened did the Speed Dial turn easier continuing in the same direction? I would first suspect the loop on the end of the Idler Shaft came off. That would be what dropped. JPG asked which way you were turning it and depending on that would indicate if this is what happened. It does sound like you need to open it up and do some checking followed by some maintenance. If your Mark V 520 was originally a 520 it would have the "C" Headstock and the rear inspection access can be found by removing the screw on the bottom of the rear Logo Plate and rotating it up. If it is an earlier "B" Headstock and upgraded to a 520 the rear Logo Plate uses a clip and pops out. The picture below is a view of the inside of a Headstock from the bottom with the motor removed. The arrow is pointing to the button bearing which has the loop that goes around the end of the Quadrant Assembly part number 504221 and reference number 86 from the link Ed gave you for the Headstock exploded parts diagram. You can see this headstock is not in the best condition but can be made to be just like new and function properly.

Headstock inside view.jpg

Take pictures of anything you have questions about and post them with those questions. As they say a picture is worth a thousand words. Pictures may need to be downsized to be able to post here. Pictures taken with my cell phone are about 4 X larger in file size than can be posted here. Cropping the picture to show only what is being asked about can sometimes be enough to get them to a small enough in file size or reducing the number of pixels.