Monday, July 15, 2013

Taming Bandsaw Vibration

I love my bandsaw.  It is a rugged 12" Atlas with a cast iron frame and good blade guides that was made in Kalamazoo, MI in the early 1950's.  When I bought the saw a few years ago it was in rough shape, but it had good bones and an almost new 1HP Baldor motor (which alone was worth more than the asking price for the whole setup).  One of the things I like about buying vintage machinery is that in order to get it to perform well, you often have to take the whole thing apart, clean and lube it, and then put it all back together again.  The process is far from plug and play, but by the end I know the machine and all of its quirks inside and out and that base of knowledge helps me to properly tune and maintain my tools at a very high level.

My Atlas 912 bandsaw.

When I was tuning up this saw I did all of the standard things to minimize vibration.  I replaced and crowned the tires, aligned the wheels, aligned the motor pulley and drive pulley, and upgraded from a standard v-belt to a link belt.  That initial tune up got the saw into good shape and it has performed admirably for me for three years now, but it has always been a little nosier than I would like and there was a noticeable vibration in the table while the saw was running.  Every now and then I would try something small to eliminate a little more vibration and noise, always coming shy of the quiet vibration free bandsaw of my dreams.

I have known for a while that the thin sheet metal wheel covers were creating a lot of noise, so most of my vibration reducing efforts have focused on them.  Last week I finally had a the vibration destroying breakthrough that I have been seeking for the last couple of years. 

While the saw was running I placed my hand on the center of the lower wheel cover and the noise and vibration were immediately reduced.  I took my hand off.  The noise and vibration came right back.  I took off both wheel enclosures and ran the saw without them for a few minutes and it ran smooth and quiet.  It turns out, the thin sheet metal was picking up vibrations in the saw and amplifying them. 

There were two distinct sources of noise that the saw was producing which had to be addressed separately; the hum of the center of the covers and the rattle of the edges.

Tracing the covers.

The centers of the wheel covers were humming with harmonic vibration and needed something to absorb it and keep the vibration from radiating throughout the rest of the saw.  I picked up a piece of 1/2" MDF to make inserts to attach to the inside of each wheel cover to add mass and absorb the vibration.  I traced the covers and then cut out the shapes on the bandsaw.

Traced and ready to cut.

Fitting the inserts took a couple of attempts.  The corners of the sheet metal are rounded and the MDF inserts needed to be 1/2" smaller than the outer dimensions of the sheet metal to rest flat on the center of the covers.

Inserts fitted.

I used double sided tape to secure the inserts to the wheel covers.

Double sided tape.

With the inserts in place the wheel covers had a solid, reassuring weight.

Edge wrapped in vinyl tube.

Where the edges of the wheel covers meet the cast iron frame or other pieces of sheet metal they vibrate and rattle against each other.  These areas needed a barrier to prevent the two pieces of metal from contacting.  I slit a line in a roll of 1/4" vinyl tube and slipped that over the edges of the wheel covers.

Cover installed.

With the MDF inserts and the vinyl tubing installed my little bandsaw runs like a top: quieter than I could have imagined and only the slightest vibration on the table.  Simply a joy to use.

2 comments:

  1. Great post Tim, very inspiring. I have an old drill press with similar issues and these are very fine solutions.
    Cheers.

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    Replies
    1. Bern,

      Great to hear from you. I had been thinking about this problem for months and coming up with all kinds of odd and convoluted approaches to addressing it. Then one Sunday, as I woke, this idea flashed into my mind. I immediately ran down to the shop to try it out.

      I hope you find some uses for it. It could be challenging to mount MDF in a drill press casing.

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