Thursday, July 7, 2011

Aluminum Bandsaw Table Insert

One of the guys over on the WoodTalk Online forum was complaining about the cheap plastic table insert in his bandsaw.  I had the same problem with mine some time ago, and solved it by using my wood lathe to make an aluminum replacement that fits better than the plastic one did, and is a lot less flimsy.

WARNING!!!  This article describes a procedure that might be considered outside the normal use of the tools involved.  If you elect to try this yourself, you are responsible for your own actions.  If anything described here doesn't seem safe to you, don't do it!

To begin, you'll need an aluminum blank that's at least thick enough to sit flush with the bandsaw table when the completed insert is installed.  Thicker is okay, but try to find stock that's as close to the correct thickness as possible.  Cut out a square of the material that's slightly bigger than the hole in the bandsaw table, and carefully mark two perpendicular center lines on it, as shown in the picture.

 Next, lay out the shape of the insert on the blank.  You can do this by scribing lines directly on the aluminum, or you can make a drawing on paper and glue it to the blank, as shown in the picture.  However you do it, be careful that the image of the insert aligns accurately with the centerlines you put on the blank in the previous step.

Find two small screws that you can use to secure the blank to a scrap of wood.  Then select a bit just slightly larger than the screws' diameter, and drill two mounting holes in the blank.  Place these holes in the area that will eventually be cut away to form the slot for the bandsaw blade.

Now mount a scrap of wood on your faceplate.

Install the faceplate onto the lathe, and if necessary, face off the outboard surface of the wood so it is smooth and flat.  With the lathe running, locate the center of rotation and use a pencil to place a small dot there.

Next, draw an arbitrary centerline through the dot.  Then rotate the scrap exactly ninety degrees and draw a second centerline perpendicular to the first one.

Now align the centerlines on the aluminum blank with the centerlines on the faceplate scrap, and attach the blank to the scrap with the two small screws.

You do NOT want to use your wood turning chisels on the aluminum!  Instead, grab an old file and grind a point on it similar to that shown in the picture.  You'll want this to be fairly small; mine is about 1/16" wide.

Now set the lathe to its slowest speed and use the modified file to cut a groove in the blank that's just outside the perimeter of the insert.  Make sure you're wearing eye and face protection, and go at it easy, with very light cuts.

Continue by making the groove deeper and wider until you finally cut completely through the aluminum and into the wood, leaving only the round insert mounted to the faceplate.

Use a normal turning chisel to remove some of the wood from around the outside of the blank, so that you can then use a regular file (with the lathe running) to clean up the edge of the insert.  Be careful at this point that you don't go too deep and hit the screws that are holding the scrap to the faceplate.

If you have an accurate way to measure the diameter of the insert, continue filing until you reach the correct size.  Otherwise, "sneak up" on the fit by repeatedly filing a little bit and then removing the faceplate from the lathe so you can test the size of the insert against the actual hole in the bandsaw table.

When you have the diameter correct, use the modified file to cut a little rabbet around the perimeter of the insert so that it sits flush with the table surface when installed.  Again, you may have to "sneak up" on a good fit by repeatedly removing a small amount of material and then checking the insert against the actual hole in the bandsaw table.

Now you can remove the insert from the face plate, cut out the slot for the bandsaw blade, and clean everything up with a bit of sandpaper.  This is what the top side of mine looks like.

And here's the bottom.

2 comments:

Vic Hubbard said...

Very nice. I don't have a lather and would actually prefer a softer material for my insert. But, that said, I do need to make a new insert, as my plastic one is a bit chewed up. I'll do mine from plywood.

Robert Thresher said...

What a great idea, good picture details to! I've been thinking how to do this for my 1970ish 20" Rockwell Bandsaw. There are no factory inserts any more, and none of the aftermarket suppliers make one for it. So thanks a bunch. I have a shop smith Mark V in the shop, and will use it to do just as you have suggested.

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