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A very acute angle jig for the bandsaw

Posted: Mon Feb 03, 2014 9:59 pm
by JPG
Been working on a holding jig(miter gauge) settable to very small angles that are beyond the miter gauge range last week. I need to cut a 11 degree cut on the end of some 2 x 6 's. End tapers 1 1/4" in 6 inches in the narrow edge.(5 1/2" deep cut hence the bandsaw)

Had a small piece of melamine surfaced particle board and a nice 1 x 6 oak board.

Squared the particle board and cut a groove in both the top and bottom to fit a SS miter bar. The bottom mounted miter bar slides in the bandsaw table slot. The top groove was intended for use as a method for setting the angle, but was abandoned as a simpler method(or two) came wandering in.

The oak board was face glued to increase it's thickness. I did not face plane it so a bit of gap occurs at one end. I flipped the board back on itself for lack of a better way. The face runout was acceptable.

Left side(bandsaw blade side) view. Note the bandsaw table is separated from the saw for this endeavor.

[ATTACH]23945[/ATTACH]

The bottom groove positions the miter bar. Note the ability to mount the bar at three locations. In the middle is shown, but it can also be mounted near each end. The bar is secured with two #8 wood screws and a 3/8" screw(bolt for those still in the dark).

[ATTACH]23946[/ATTACH]

A narrow 'foot' was attached to the face that was sanded to 90 degrees from the face with the conical sanding disk. The 'foot' holds the face at 90 degrees from the base.

The washer under the screw head was filed(double d shape) to allow it to slip into the top side groove.

A clamp holds the upper piece in position. It slides along the right edge, and the table extension keeps it from slipping off the edge(see next pix). The extension does not get involved in the actual clamping.

[ATTACH]23947[/ATTACH]

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The lip facing up in this pix slides under the bandsaw table. and the smaller lip facing down slides on the table extension. The clamping surfaces of the table lip and the walnut spacer are slightly tapered so as to increase the clamping force of the top clamping piece.

[ATTACH]23949[/ATTACH]

Less said about the 'inlay' the better!:D

Posted: Mon Feb 03, 2014 10:00 pm
by JPG
The top piece of the clamp can be used in different orientations. It needs to be longer at small angle settings with the clamp near the end. More about the clamp pivot holes later(it is not centered side to side).

[ATTACH]23950[/ATTACH]


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The 'main' pivot consists of a 3/8" screw that passes through a hole in the 'face' piece. The holes in both the base and the 'face' piece are counterbored to accommodate nylon bushings and a nylon shouldered washer. The through hole is slightly oversize(>3/8"). A flat washer and coupling nut(what I had in hand) top it out, but do not perform any clamping function.

[ATTACH]23952[/ATTACH]

Notice the double counterbore to accommodate the shouldered washer(above), and the bottom edge relief cut to allow for debris(below).

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An added 'attraction' - A t-slot on the top edge. I do not know what this hunk of oak will be used for in the future, but I just wanted to prove to myself I could make one!:)

[ATTACH]23954[/ATTACH]

Posted: Mon Feb 03, 2014 10:01 pm
by JPG
The clamp parts. Made from scraps.

[ATTACH]23961[/ATTACH]

Added a couple of holes to provide added flexibility.

[ATTACH]23962[/ATTACH]

So how does one set the angle? IF one has one of these gizmos, tis a piece of cake(spacer needs parallel sides).

[ATTACH]23963[/ATTACH]

If not use the SS miter gauge slipped between the right table edge and the table extension(pix next post). 90 - 75 = 15 degrees.


[ATTACH]23964[/ATTACH]

Then position a combination square head between the miter gauge and the back side of the 'main' piece.

[ATTACH]23965[/ATTACH]

Posted: Mon Feb 03, 2014 10:01 pm
by JPG
The miter gauge bar will slide between the right side of the table and the inside edge of the table extension. The bar rests on top of the extension table support bar.

[ATTACH]23968[/ATTACH]

The right edge of the table has flash that can be easily removed to improve thus.

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I have not included a way to secure the 'main' piece from moving away from the clamp. Since it will be pushed when cutting a 2 x 6 clamped to the 'main' piece, I do not anticipate a need for one.
If that proves overly optimistic I will add pix of what I do here. Most likely that will be a groove in the top face of the back bottom piece and a part on top of the clamp that drops into the groove.

Posted: Tue Feb 04, 2014 12:21 am
by reible
I'm going to have to sleep on this. I've read it twice but I still don't "get it".

A fresh perspective in the morning never hurts.

Anyone else confused?

Ed

Posted: Tue Feb 04, 2014 12:32 am
by JPG
reible wrote:I'm going to have to sleep on this. I've read it twice but I still don't "get it".

A fresh perspective in the morning never hurts.

Anyone else confused?

Ed
Understandable. An odd need for a 11 degree cut. The cut starts on the end 1/4" from the wide face and continues to exit 6 " from the end as it exits the opposite face. The waste piece is a wedge 1 1/4" x 5 1/2" x 6 ".

The 2 x 6 are 5 ft long.

I am awaiting another 50 degree day to try this out outdoors. Last night we got 4" +.

Posted: Tue Feb 04, 2014 9:40 am
by anmius
Couldn't you have accompished the same thing by attaching a 90 degree block to the miter gauge? You could set the miter gauge with your Miter Set for the complimentary angle and just attach the 90 degree block.

Posted: Tue Feb 04, 2014 11:46 am
by JPG
anmius wrote:Couldn't you have accompished the same thing by attaching a 90 degree block to the miter gauge? You could set the miter gauge with your Miter Set for the complimentary angle and just attach the 90 degree block.

Thought about that. The 5' length and 5 1/2" height of the 2 x 6 becomes troublesome. I felt I needed a longer 'reference' surface, so the jig was built. I would have had to make a 90 degree 'block' anyway.

The oak piece comes close to that anyway.

I do not have faith in being able to hold the 2 x 6 etc. tight to the miter gauge. The jig at least has geometry and force vectors on it's side.

Either way I believe the feed force needs to be applied to the workpiece directed at the blade, not the applied to the jig/miter gauge.


Truth be told I backed into this and got carried away by the construction details. I thought those details might be of interest.

Not mentioned above, was the melamine faces were scored by a very shallow preliminary cut prior to cutting the grooves. No tearout!:)

Posted: Tue Feb 04, 2014 3:45 pm
by keakap
JPG40504 wrote:...
Truth be told I backed into this and got carried away by the construction details. ....
Not that could ever happen here!

But I seem to remember from long ago, went into the "shop" (garage containing Shopsmith) to do a specific thing, three days later finished a complicated but nifty "jig" that would do a number of things (that I had no plans of ever doing) and as I readied it for its first real task it occurred to me what I had come here to do- wax the way tubes.

Posted: Wed Feb 05, 2014 2:19 pm
by jimthej
keakap wrote:Not that could ever happen here!

But I seem to remember from long ago, went into the "shop" (garage containing Shopsmith) to do a specific thing, three days later finished a complicated but nifty "jig" that would do a number of things (that I had no plans of ever doing) and as I readied it for its first real task it occurred to me what I had come here to do- wax the way tubes.
AAADD! Age Accelerated Attention Deficit Disorder! :D :D :D