Shopsmith Forums

the porkchop in my '76 M5 is soft aluminum - is there any reason to believe a new one will be made of a harder grade? (I have one on order, just curious)

I don't know but I doubt it!! However, there is a real good way to keep your new one from looking the same .

Clean and lubricate the headstock "frequently" and do not speed dial your speed changes.

NO. I believe that the material being used in the quadrant is the best product for manufacturing, durability and price. When dealing with worm drives, you may need to have one of the parts a softer material so the parts wear in better and as a fail safe solution. There is a lot of design issues when dealing with this type of drive.

Total Shop and some other clones used a brass quadrant so I still found the teeth broken or one of the arms holding the quadrant will break off which was a more expensive part than the quadrant. Same major problem area as the Shopsmith from lack of lubrication.

On every Speed Control Quadrant with damaged or managled teeth, I find the Control Sheave or the Floating Sheave is stuck or is very difficult to move.

If the Control Sheave is lubricated often and with enough oil (12 to 20 drops) along with the motor Floating Sheave (4-8 drops in oil hole and oil on the key and exposed motor shaft), Speed Control at FAST, I do not believe you will ever have any problems with the Speed Control Assembly on the Shopsmith. I have done this on many Mark V headstocks for more than 30 years without any failures.

Of course, the free bolt kit (10-32 X 2 1/2" allen head bolt, 2 star washers & nylock nut) I offer for use in place of the quadrant roll pin does stabilize the position of the quadrant and helps prevent the worm gear from wearing on the edge of the quadrant teeth. I do not know of any failures after installing a few hundred bolt kits. I did present this upgrade to Shopsmith years ago but liability issues prevented them from accepting.

We can only speculate on why the quadrant is 'soft', but the reasons mentioned above are entirely plausible.

As Bill said, lubrication is a preventative measure.

Dusty has also said do not speed dial.

To both I add go slow towards slow.

Going fast towards fast is not a problem!:)

If you have to 'force' it, find out why and correct the cause.

Part of the cause of excessive wear is the shape of the quadrant gear teeth. They are helical(angled spur gear) teeth, not worm gear teeth. The root of the teeth are straight, not curved to match the curvature of the worm gear. This creates a small area of contact between the gear surfaces. At best this combination produces line contact. Since when properly lubricated and properly adjusted, minimal damage occurs, the design is adequate. Alter those conditions and excessive wear will occur.

[quote="JPG40504"]Part of the cause of excessive wear is the shape of the quadrant gear teeth. They are helical(angled spur gear) teeth, not worm gear teeth. The root of the teeth are straight, not curved to match the curvature of the worm gear. This creates a small area of contact between the gear surfaces. At best this combination produces line contact. Since when properly lubricated and properly adjusted, minimal damage occurs, the design is adequate. Alter those conditions and excessive wear will occur.]

The Total Shop and other clones had the brass quadrant teeth curved to match the worm gear and was wider than the Shopsmith quadrant. This required more machining for the teeth. Yes, the teeth did not wear as much but they tended to break off or cause the legs that supports the quadrant to bend and then break. Again, the control sheave was stuck in most cases. I found almost all the Total Shop and clone problems were in the speed control assembly, just like the Shopsmith.

enyoc wrote:the porkchop in my '76 M5 is soft aluminum - is there any reason to believe a new one will be made of a harder grade? (I have one on order, just curious)

If you have not already done so, do take up on Bill's offer for parts to replace the tension pin pivot. The posts on yours are bent and that will cause the new porkchop to wear the same as that shown.

JPG40504 wrote:If you have not already done so, do take up on Bill's offer for parts to replace the tension pin pivot.

I have! The generosity of the folks on this forum is incredible!

JPG40504 wrote:The posts on yours are bent and that will cause the new porkchop to wear the same as that shown.

How can you tell? Will replacing just the porkchop be enough in my case?

Thanks all for your inputs and advice!

The porkchop should be in alignment with the shaft directly below it (in your picture). It is this ma-lalignment that causes the wear on the porkchop gears to be off center.

If they were not bent, you may still see signs of wear and tear but it would be more-or-less centered on the porkchop.

Replacing the porkchop without doing anything else will do little if anything to correct your problem. But the problem can be resolved (with Bill's kind offer) and a little bit of pressure to realign the support legs that are bent.

Is there a consensus on what the best lubricant is to use on the pork chop? It seems that any "wet" lubricant will attract sawdust and dry lubricants just don't last.

this is interresting to me, If i may ask a related question.
when dialing my V 500 to slowest point , the last 1/4 of the dial get harder to back off. I go from using the dial handle to full hand grip on the dial to back it all the way down. what should I look into here. Thanks for sharing your question, info and pic.