Bandsaw Tire Crowning Using Angle Grinder

Modified on 2010/03/03 09:32 by Jeff Joslin Categorized as Bandsaws, Restoration Topics

''By [http://www.owwm.com/members/detail.aspx?id=7885| bambusero], originally from an [http://owwm.org/viewtopic.php?t=33607|owwm.org forum post]''

I have spent the last month figuring out if I wanted to use Bob Vaughan's method with a jig and a die grinder. I was really nervous about a carbide bit cutting 1/8" away from my precious CI wheel. I just didn't trust myself that much.

And I was considering building a jig to put on the 12" disc sander, sort of an adaptation of a milling machine. I was going to have to turn a tapered axle for the lower wheel, so I was really going to have to make two jigs... too much work. 

But the magic ingredient for me is the angle grinder. I have yet to find a problem I couldn't solve with an angle grinder. I like to call it the "carpenter's toothbrush". 
So here's what I came up with: 

[image|Jig for upper wheel|{UP}BandsawTireCrowningAngleGrinder/upperjig.jpg]

[image|Jig for lower wheel|{UP}BandsawTireCrowningAngleGrinder/lowerjig.jpg]

[image|Closeup of the grinder in action|{UP}BandsawTireCrowningAngleGrinder/angle.jpg]

I used the tapped hole for the side handle, and a quick release pipe clamp to hold the grinder in the jigs. The jigs are attached to the frame by the same bolts that hold the cabinet and blade guard castings. One bolt is a pivot, and the jig has arc (for the second bolt) to allow the grinder to swing into the cut.

To get the angle for the bevels, I thought of several complicated ways to hold it, but just ended up eyeballing and shimming until each cut angle was set. That was the vast majority of the work. I also considered using a long carriage bolt to make a feed mechanism, so that I could control the depth of cut, but I just ended up tapping the jig with a hammer, and adjusting the tightness of the bolts to control the cut. 

Oh yeah- I used a 60 grit disk on a backer pad.

[image|How it looked mid-process|{UP}BandsawTireCrowningAngleGrinder/crowning.jpg]

And I could even check the crowning with a blade, without removing the jigs! 
[image|Testing blade tracking|{UP}BandsawTireCrowningAngleGrinder/testing.jpg]

Despite my trepidation, it appears to have worked just fine. I almost managed to fry my angle grinder, not sure if I pinched it too hard with the pipe clamp and deformed the motor windings slightly, or if I shouldn't have been using a router speed controller. Thankfully, it worked fine after a cool down break

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