# Wood for Bandsaw circle jig



## Starfury (Jul 1, 2015)

I've had my bandsaw for a while now and I want to make a circle jig. I have plans I'm going to use BUT I have a question about the material. I do have some scrap 1/2" plywood (it's 10+ years old so way better than what's currently sold) but it's all a bit bowed. Since the jig plans call for doubling up the wood on parts would it work to just reverse the bow to each piece then glue/screw them in place? The bowing is minor…maybe 1/4" over a 4' span. I did debate on getting some Baltic birch..but it's about $40 for a 5×5 sheet of 1/2".

Should I just spend the money on some good plywood or use what I have? I want to build it once and have it work right…not cheap out then have to re-do it or have a crappy jig.


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## GR8HUNTER (Jun 13, 2016)

maybe you can build in bracing with hinges so as you could fold it up when not in use


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## TravisH (Feb 6, 2013)

Your plan will work fine if you decide to go that way. No more time gong to be spent in your case using the slightly bowed sheet good versus flat based on the described construction process.


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## CharleyL (Mar 10, 2009)

How big of a circle do you want to cut? How accurately do you want to cut it? Will you be keeping it so you can use it again, or do you plan on throwing it into the scrap pile when you finish using it? Your circle jig quality and design will depend on the answers to these three questions.

Take the time to make a good quality, and foldable, if desired, circle jig that will do a good job this time and every time that you want to use it in the future. My shop ceiling has many jigs that I took the time to make right, so I can, and do, use them again and again. My band saw circle jig 
is bungee strapped to the back side of my band saw. It will make circles up to 4' in diameter, and I made it 20 years ago. It's another quality tool that I frequently depend on in my wood shop. I made it once, and right, 20 years ago.

Charley


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## BillWhite (Jul 23, 2007)

Melamine. Done.
Bill


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## Tootles (Jul 21, 2011)

You possibly could reverse and glue/screw but (a) you would not know the outcome until you actually did it, and (b) would the positioning of the screws that you use to flatten the ply be in your way for the jig?

Then again, you may have answered your own question …


> I want to build it once and have it work right…not cheap out then have to re-do it or have a crappy jig.
> 
> - Tom


I just used about 3/4" MDF for the one I made. It's smooth and flat (and I already had the MDF in the workshop). Even if it was not completely flat, it would not have bothered me. It is mostly used by my students to cut dials for clock faces, and absolute perfection in either dimensions or squareness of the edge is not the main focus of the project.


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## Rayne (Mar 9, 2014)

i second the use of MDF or Melamine. Both are flat and won't move. If you go MDF, just seal it in case any kind of moisture gets on it accidentally.


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## Starfury (Jul 1, 2015)

I dropped $40 on a 5×5 of 1/2" baltic birch plywood. Going to build the jig out of that and also a table saw sled. Decided the other plywood is good for less precise uses.


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## CharleyL (Mar 10, 2009)

Smart move, Tom. You won't regret it.

Charley


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## kelvancra (May 4, 2010)

I've made several. From that, I've learned you can make the jig from about anything you want. In the end, it's as much an aesthetics thing as anything else.

Any wood shift differences between particle, ply and such are not going to be significant enough to note. Of course, if you use boards and they function as a porch roof for rain when not in use, that may not be accurate.

I would say a couple things will make it a better jig:

1) Use aluminum guides for long life (I buy 3/8" flat stock from local metal suppliers and cut a bunch of 3/4" wide guides to have on hand for jigs). Of course, hardwood works too.

2) I designed mine with the table reaching all the way over to the post. Doing this means most of the dust is not thrown to the left side of the blade, all over the table and in the air. Instead, the jig acts like a big throat plate and the dust and such is carried down into the collector port section. Too, the extra weight acts as a counter balance for larger (e.g., 30" plus) circles.

3) Set the jig up with a stop, so you just push the stock into the blade and the jig stops with the teeth lined to the pivot pin, so you don't have to rough cut anything and there is no guesswork. From there, it's just a matter of staring the spin.

Here is my version with the improvements I noted: http://lumberjocks.com/topics/69321

I also built an extension table to support larger pieces. It attaches and removes in seconds, with no tools. It helps a lot, when I was cutting thirty inch lazy Susans for over-fridge cabinets. It's also proven useful in re-sawing and other operations:

http://lumberjocks.com/topics/59980


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