The Band Saw is Up and Running Again

Back Together and Fully Set Up

As of 7:30 tonight, the band saw is back up and running well. The repaired saw is shown fully reassembled at right. The new trunnions fit perfectly, though final adjustments turned out to be more finicky than I expected. As long as I had the table off, I decided to clean, lubricate, and adjust the upper and lower blade guide assemblies. These were heavily gunked up with pitch, sawdust, and the overall residue of the past seven years of use. Some of the guide adjustments were almost too stiff to move while others had enough play as to make accurate setting impossible. A minor overhaul seemed to be in order.

Blade Guides (Front) and Trunnions (Rear)

The next photo shows the new trunnions along with both blade guide assemblies. The guide assemblies incorporate both aluminum and steel components, so I decided it would be best to strip them down completely for cleaning. Formula 409 and a toothbrush were quite effective at de-gumming the aluminum parts while mineral spirits were used on the steel parts.

Each guide assembly contains a ball bearing, visible in the photo, which sits behind the blade to absorb its rearward thrust during cutting. Both of these were stiff due to lack of lubricant. I would like to have replaced them, but at a cost of $21.00 apiece from Delta, I decided to salvage them. I was able to pop the grease seals off with the tip of my utility knife, flush them out with solvent, and repack them with lithium grease. After all this work, I located a bearing distributer online who offers them for $0.99 apiece, plus shipping. Although I have not yet placed an order with these people, I think their site at http://www.vxb.com is worth checking out.

The two black shafts in the middle of the photo are the adjustment screws for the lower guide assembly. These steel screws turning in the aluminum guide assembly are prone to galling and similar issues, so I was meticulous in cleaning these up and lubricating them. One moves the thrust bearing forward and back behind the blade. Properly adjusted, the bearing sits a few thousandths of an inch behind the blade, only contacting it and actually spinning when the blade flexes under the pressure of a cut. The other adjusts the guide blocks which keep the blade from flexing side to side. These have to be adjusted so they sit just behind the saw teeth so the blocks do not get chewed up in the process. I have replaced the original steel guide blocks with graphite impregnated phenolic "cool blocks" which can be set more closely than steel blocks without risk of damaging the blade, thus providing a more accurate cut.

Checking the Position of the Broken Trunnion
 Prior to Removal

As I said previously, final adjustment of the new trunnions turned out to be problematic. Before removing the old trunnions, I made measurements with a steel square hoping that would make the final adjustment easier.

The photo at right shows me carefully measuring the position of the broken rear trunnion prior to removing it. In practice, these measurements only provided a starting point. I did the final adjustment by making an endless number of test crosscuts on the saw using the miter gauge and moving the table to compensate for deviations from square.

It took about thirty minutes to get the table accurately adjusted, which also turned out to be the limit of my patience. Since the new trunnions seem to be better made than the original parts, I have hopes of never having to go through this process again. Only time will tell. In any case, I am now able to resume woodworking rather than machine maintenance, so I should be able to get back to the Shaker Sconce project for my next post.