Miter jig build

[dave]

I want to build a jig to make quick and accurate work of miters for frames and boxes. I've drafted a design in sketchup, which mimics designs I've seen elsewhere, but I added an idea I had on how I could miter the sides for boxes and possibly do more than one at a time (we'll call it the "miter bucket").

I'd love to get some feedback and suggestions on this. Is the design sound or will I encounter problems or accuracy issues with it?

The miter bucket will have pins/dowels on the bottom to align it with the base and hold it in place. I am also thinking I'll add some type of clamping system to it, but want to give that some more thought.

Lastly, what's the best material to build this out of? I was planning on a piece of 3/4 plywood for the base, but was not sure what would work best for rest of it.

Here's a few images of the design. Thanks for looking!

 

[Joe Scharle]

First thing I see is the captured cutoff flying out of the 'bucket' with the probability of a snipe cutoff at the end of the cut. The cutoff will be free but most of the blade still in contact with the workpiece.

However, I'm curious as to how it works out for you.
Joe

 

[FredP]

not sure I like the bucket. the cut off piece is going to lay on the blade after it is cut. I see bad things happening with that design. [binding?] also, how do you get repeatable accuracy? the slot will allow the piece you want to cut to slip down into the kerf. you could clamp this piece but getting an exact length of cut looks iffy. the dubby design without the bucket is a proven design.

 

[dave]

Good point guys and exactly why I asked! :wsmile:

I wonder if a "half bucket" design would work.... off to sketchup again!

Thanks!

 

[FredP]

Good point guys and exactly why I asked! :wsmile:

I wonder if a "half bucket" design would work.... off to sketchup again!

Thanks!

half bucket would allow the cut off to fall away from the blade. you realy dont need to cut on both sides of the blade if the jig is eggzakary square and a prrrrfict 45*:gar-Bi

 

[Dudelive]

I would think a sliding sled on the table saw would be able to be more accurate and a proven design also and safer.

just my opinion

 

[FredP]

I would think a sliding sled on the table saw would be able to be more accurate and a proven design also and safer.

just my opinion

it would,:thumbs_up but I see the advantages of not having to move the blade off of 90*.:widea: remove jig, make a rip, replace jig and not have to crank the saw to 45* then crank back to 90*. for this type of cut 90* has to be absolute. A little sawdust on the adjustment screws could throw off the angle. I personally hate cranking my saw to cut bevels. I use the miter saw for those type cuts. :gar-Bi

 

[dave]

That's exactly my thinking here Fred. I don't want to have to change the blade angle any more than I need to.

Here's a revision. Basically opened up a window for the waste to fall through.

 

[FredP]

possibly so long as the cut off doesnt get trapped and forced against the blade. having both sides available makes it easier to get a good fit so long as the 2 angles = 90. you are planning to clamp the work piece.... correct? I would use dual runners for this using both miter slots.

 

[CarvedTones]

A note and a question or two...

I agree about the 90 degree blade for accuracy. It is easier to set reliably and your jig's edge is exactly where your stock gets cut; a reference point for measurements.

How wide is the stock? Can you do it on edge?

 

[FredP]

A note and a question or two...

I agree about the 90 degree blade for accuracy. It is easier to set reliably and your jig's edge is exactly where your stock gets cut; a reference point for measurements.

the bottom needs to open to allow the cut off to fall away from the blade.

How wide is the stock? Can you do it on edge?

if the sled is 3/4" thick you will only be able to cut 2 3/8+/- deep with the stock on edge. the more I mull this over the more it looks problematic. try it and give us some feedback on how it works.:wsmile:

 

[CarvedTones]

Two more points on cutting on edge.

1 - The offcut may not be an offcut at all. If it is a board and application where both faces are fine, you could run it through like a skewed crosscut sled cutting two corners at once because if you flip one over and put the corner together and it is guaranteed to be 90.

2 - Either it is accurate or it isn't and I am assuming it is. If it truly is, you can double that maximum because you can swap the ends and faces and run it through again. If you can't do that, you aren't getting the accuracy you're after to start with.

 

[Travis Porter]

half bucket would allow the cut off to fall away from the blade. you realy dont need to cut on both sides of the blade if the jig is eggzakary square and a prrrrfict 45*:gar-Bi

I don't know about you, but I don't own many jigs that are "eggzakary square and a prrfict 45*"??

 

[dave]

Quick update - got the jig built or at least what I'll call the first draft. Did not do the bucket... it's more like a ramp now.

Ran several tests and so far I am impressed. Probably the best corners I've ever done (but that's not saying much!). :gar-La;

I think if I can fabricate a realiable and safe way to hold the work piece in place, I'll be in business. Tonight I just cut four 5" pieces and then mitered each end. They all came out the exact length and fit together almost perfect. One piece I did overtighten the clamp which threw it off a bit.

I'll break out the camera and get some pics up, but might be tomorrow on those.

Thanks for all the feedback!

 

[junquecol]

Check out the "Top Tip" in Wood, July 2008, issue 184, page 14. Col. Joy Wood, USAF-Ret. designed such a jig to cut flag case parts. Includes material rest, and clamp assembly. Mitered parts can be turned over and slotted for splines using her jig. I can't scan you a copy, but I do have the magazine, and a copier.

 

[CarvedTones]

I don't know about you, but I don't own many jigs that are "eggzakary square and a prrfict 45*"??

Thas cawz you bin byin Steel City insteda Arn Tawn... :rotflm:

 

[dave]

Thanks Bruce, I'll look that up!

Here's the pictures. I am planning on modifying (refining) the jig more. I think I will end making it a separate jig altogether on the left side of the blade and making the sled half the size... plus creating a clamping system.