What parts are compatible on 500, 510, 520

[tprowood]

I’m looking for some repair parts online. I need a quadrant, idler shaft. I have a mark v 500. Some of the listings say parts from a 510 or 530 will fit a 500. But I’m not 100% confident. I have a mark 5, serial is SS 42594.

[DLB]

When in doubt you can use the parts listings to check PN and see if that PN is used in later models. (https://shopsmith.com/service-parts/mar ... 0-505-500/)

Quadrant - Assuming you mean the speed control quadrant (aka porkchop) the listings for 520, 510, 500 etc. they are the same. I would not buy a used quadrant unless there were photos establishing it is in perfect condition. It is a high failure part subject to wear, especially on any machine where it becomes difficult to adjust speed. It's also available as part of a speed control assembly (both new and used). Before buying it by itself, you want to make sure the legs it attaches to via spring tension (aka roll) pin are straight and the holes are round and not excessively warn. Considering reinforcing this whole thing using the Bill Mayo headstock improvement as a guide. (download/file.php?id=34357) This strengthens the weak points and gets rid of the concept of using a roll pin as a hinge pin.

Idler Shaft - These are also generally compatible. If it comes with sheaves, make sure you get a Poly-V and not a Gilmer. If it is the new style bearings it must have a new style eccentric with the split. IIWM I would try to buy the old style bearing with the new style eccentric because these are newer than those with the old style eccentric. Examples:

Idler w new eccentric.jpg (52.96 KiB) Viewed 299 times

Idler w old eccentric.jpg (54.57 KiB) Viewed 299 times

In these examples, borrowed from current ebay ads, "#4" is newer than #3 but not new enough to have the new style bearings. That, in my view, is the sweet spot.

- David

[tprowood]

Thanks. My idler looks exactly like #3. But, you’re saying #4 would be a better choice?

[DLB]

Thanks. My idler looks exactly like #3. But, you’re saying #4 would be a better choice?

Yes, only because the split in the eccentric bushing suggests that it came out of a newer machine. I've not heard of very many Idler bearing failures with the water pump bearing, and I haven't experienced any. I would trust an old one too, but given a choice I'd rather have one that is 15 or 20 years old than 40 or more.

- David

[chapmanruss]

tprowood,

Not all sellers of used Shopsmith parts understand the differences between the Mark V Models and therefore tend to list the part from the model it came from. Even then they don't always label them correctly. Sometimes it is more important to know what year it was made when looking for Mark V parts to better match what you have. This is not to say you can only use parts from your era of mark 5/V but any Headstock made prior to 1961 with the Gilmer Drive will need those specific parts or be upgraded to the Poly V Drive the Mark 5 changed to in 1961 and still are used today. As David pointed out it is better to get Speed Control parts that are in like new condition when buying used or if any doubt buy new parts from Shopsmith. On the used market it is up to the buyer to know if they are getting a good usable part or not. I am restoring an April 1961 Mark 5 Goldie and purchased a new Speed Control Assembly for it to replace its worn assembly. The Speed Control Assembly is something the has been essentially the same since the introduction of the Mark 5 in 1954.

Your Mark 5, serial is SS 42594 was made in August 1979. This predates other Mark 5/V Models. It is the Table/Fence system including the carriages and other accessories that make the difference between the Mark V Models 500 (original table system) and the 510/505 & 520. The conventional Headstock and Bench (until recently) are the same between all the Mark V models. This does not affect your Mark 5, but early Mark 5 tools had larger diameter Bench Tubes and therefore different Bench Ends then the mark 5/V's made in the 1960's and on. With the Mark V 520s coming out the Bench ends changed to the Double Tilt ends like the ones found on the current Mark 7 and Mark 4. The most changes to the Mark 5/V over the years has been in the Headstock. Some parts can be changed individually while others must be changed as an assembly.