Shopsmith Forums

Hi, I am a new owner of an old Mark V ( I think) and new to to this forum. I've been cleaning and taking stock of what parts I need to replace and am trying to order a Quadrant Assembly part 504221. It is definitely worn out. So can someone explain to me how the speed adjustment of the whole machine works or send me to a link with an explanation. I'm wondering what caused the failure of the assembly. I've look at some pictures on this site and my belts are not in the same position on my pulleys as in the picture. Missing quite a few parts for the table saw and lath but will be able to use the band saw, drill press and a home made disk sander. Very excited to get it running.
Thanks in advance
Doug in Alaska

What do you mean when thee say definitely worn out?

We need to nail down what model you have. What color is it?

BTW a picture is worth many words.

Most important is adequate lubrication of the movable sheaves(light machine oil). [3 in 1, sewing machine, turbine, Zoom spout]

Oh and welcome to the funny farm.

Doug,

Welcome to the Shopsmith Forum.

Lack of proper maintenance is the main culprit causing wear on the system. Failure to adequately lubricate the movable Pulley Sheaves on the Motor and Idler Shafts put extra stain on the Speed Control. Lack of lubrication on the gears of the Speed Control Assembly will wear them out too. The Speed Control Assembly gears should be lubricated with a dry lubricant as opposed to the Pulley Sheaves being lubricated with a lightweight oil. Dry lubricant is a better to use on these exposed parts to avoid attracting dust and debris which will "gum up" the parts. Don't forget to use the dry lubricant on the gear teeth under the Speed Control Handle too.

The bearing on the back of the floating Sheave on the Idler Pulley Assembly can "freeze" causing problems which start with the wire loop that goes around the end of the Quadrant Assembly breaking off. Like other "permanently" lubricated sealed Bearings used in the Headstock it can "lose" that lubrication with age and other factors and no longer turn like it once did.

Do check that the Worm Gear is in good condition still or you may have problems in the nearer future with the Quadrant Assembly wearing out too soon again.

All Conventional Headstock Mark 5/V's use the same Speed Control Assembly parts (other than the Speed Indicator Dial) from the first Mark 5 in 1954 through the current models. There were a couple of Speed Control Assembly changes from the "A" Headstock to the "B" Headstock in 1955. Other parts in the drive system from the motor to the Quill and parts in between have changed over the years. This is why it is important to know when your Mark V was made and if it has had any upgrades.

My machine is gray and SS # 23925 if that helps. The threads on the aluminum Quadrant are stripped (worn). The brass worm gear looks ok. I found a YouTube channel last night which was very helpful. His channel is Jacob A. I understand how the speed is adjusted a lot better now. I'm going to have a better look at the pulley belts. I've lubricated the pulleys and they seem ok. I am trying to order the Quadrant assembly but the ShopSmith site won't mail to Alaska without calling them so I need to do that today. I can't run it on low speed until I replace the part.
Thanks for your help JPG and Capmanruss .

Teewy wrote: ↑Wed Mar 22, 2023 12:45 pm My machine is gray and SS # 23925 if that helps. The threads on the aluminum Quadrant are stripped (worn). The brass worm gear looks ok. I found a YouTube channel last night which was very helpful. His channel is Jacob A. I understand how the speed is adjusted a lot better now. I'm going to have a better look at the pulley belts. I've lubricated the pulleys and they seem ok. I am trying to order the Quadrant assembly but the ShopSmith site won't mail to Alaska without calling them so I need to do that today. I can't run it on low speed until I replace the part.
Thanks for your help JPG and Capmanruss .

Before replacing just the quadrant, carefully check the condition of the 'legs' it mounts in. The legs must be straight and the holes that the quadrant swings in must be round and not worn over-sized. Anything that causes the quadrant to not swing true on its hinge point can cause premature wear of the new quadrant. I'd also recommend a careful inspection of other parts, as Shopsmith shipping is not something you want to pay repetitively even to the lower 48 when it can be avoided.

There is a document by the late Bill Mayo on improving the robustness of the speed control and allows for some damage to the legs. It is well worth reading even if you opt not to make the improvements. See: (viewtopic.php?p=185690#p185690) fourth attached pdf.

Good luck, and welcome to the forum.

- David

Thanks David. I'll have a careful look at the whole assembly. I downloaded the PDF and will read it today.
Thanks for your help.

OK Update. Ordered a new quadrant and installed it. The assembly looks good and I can now turn the machine to low speed. All pulleys shafts are lubricated, Belts look good and bearings feel fine. I noticed while installing the speed assembly that the flange that the assembly screws to is warped, probably bent by using excessive force when changing the speed ( not by me). The hole is also stripped. The screw hole that the Spring Dial is attached to is 1/8th of an inch further out than the other two. Hope this is clear to you. Has any one ever experience this? My fix it is to use two small fender washers under the opposite screws between the Control Bracket (main speed assembly body) sandwiching the speed indicator ring between and the flange. The fender washers will keep the speed indicator ring in contact with the Idler Gear. I'll have to use bolts instead of the self tapping screws. So the whole assembly will be about an 1/8th inch further out than original. Anyone see problems with this or have any other suggestions? I really don't think I can bend the flange back! Thanks for any and all advice. Doug in Alaska

If I'm understanding the problem/resolution correctly, this will change the position of the speed control quadrant relative to the 'button' and clip on the control sheave. At any given speed the contact point between quadrant and button is different from normal. You'll want to carefully inspect that interaction throughout the speed range, especially at high speed settings.

- David

Doug,

I think I understand the problem you are having correctly. That's a creative solution to the problem. I would be interested to know if it works. Besides the possible issue David pointed out the spring will no longer be in contact with the back of the Speed Indicator Dial.

Another solution would be to find a replacement Headstock casting.

Sorry for the late reply. I installed the quadrant without the fender washers because it just wasn't a good fix. Its installed the normal way and if I take my time slowing it down it works fine. Speeding it up is quick as I need and smooth. As I understand it this is normal. Have had fun using it. Mostly the band saw. Still looking for parts for the table saw and the lathe.
Regards Doug in Alaska