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Delta 6x48 Sander Shafts

Modified on 2018/04/21 16:40 by bullmastiff Categorized as Bearings, Restoration Topics, Sanders

Removing Upper Shaft

Removing spindle from Delta 6x48 sander
Removing spindle from Delta 6x48 sander.. continued
Rockwell 6x48 Belt Sander Bearings
Delta sander 31-710 bearing removal
Rockwell 6x48 sander
Starting rebuild of 31-710 belt/disk, any hints?

WARNING: Read this whole section before proceeding with removal of the upper shaft. It is not uncommon to break the idler arm casting as seen below.

A press is recommended, if not fully required. Pounding on the shaft is unlikely to move it. The clamshell drum halves are a slip fit and should just slide off but old ones rarely, if ever, do that. The steel shaft sometimes galvanic welds to the drums, requiring significant extra pressure to break the bond. In this case it will release with a loud bang so one might want to use ear protection. The image below from Bob Vaughan shows how to set up the idler assembly in the press. Do not orient the assembly up the other way. The press should be pressing on the shaft and not the bearing. Find a length of steel smaller the shaft's 15mm diameter to press through the bearing.

Even when the above technique is followed, it is still possible to break the casting. If the lower bearing is rusted in place, the lower end of the casting will be pushed down until it breaks. Some ideas to possibly avoid this are:

  • Once the shaft begins moving, look to see that the lower bearing is coming out of the casting. If instead, the casting is bending, stop. The danger here is that the casting may break before a problem is noticed.
  • Add additional support for the casting so it does not bend down. The challenge with this technique is that the casting may end up taking all the load, in which case it will certainly break.
  • A technique that has been used on a similar bearing setup on a different machine is to first remove the balls from the lower bearing: pop off the seal, drill and pry out the bearing cage, move all the balls to one side, then pop them out. Now the shaft will be free to come out without applying any pressure to the bottom of the casting. Ensure that the inner race is not catching on the outer race before applying full pressure.

Examples of Shafts and Conditions

From Bob Vaughan. Details of upper shaft problems resulting from operator ignoring symptoms of bearings going bad. Also, note the problems one will have when pressing the shafts out of the drums.
Belt sander upper shaft details
Delta 6x48 31-730 sander repair details(16 pictures)

Comparisons to Powermatic 30

By Bob Vaughan
6x48 sander drum shaft sizes

Thought I would throw this out for illustration. I've worked on both the Delta and the Powermatic 6x48's recently and replaced both top shafts. I was amused at the differences in the way they were made and the size of the bearings used. Seeing these components side by side is instructive as to why there was a price difference in the machines when they were sold new. Both of these shafts are take-outs as are the bearings.

I replace a lot more Delta shafts than I do Powermatic ones, but they both usually need the crown worked over before the shaft gets gone.

I don't know that I'm going to be seeking a Powermatic any time soon because of the footprint. My Delta 6x48 does me fine for the time being.

Shaft Fabrication

By Bob Vaughan

Shaft fabrication is easy with a metal lathe. Take 15mm ground rod (see links below for source) and thread the ends to fit the fine nuts you have. Newer shafts have different threads to older ones (see pictures above).
Rockwell 6x48 sander
Delta 6x48 31-730 sander repair details(16 pictures)
Delta 6x48 upper (idler) shaft question?

Bearing Information

When fitting extended race bearings to this sander, the extended portion of the race should be exposed to the elements, that is the races of the two bearings should extend away from each other.
Opps, 31-710 sander, ext. races, in or out? Dr. Vaughan?


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