100 Ways to Skin a Cat - Just Need One to Make a Miter Sled

[Mike Shields]

In search of perfect 45s, and one day I will find them:

Days (or is it weeks?) of research has me convinced that a miter sled in place of any aftermarket guage is the way to go. Two reasons, the first being cost. A sled can be made from scrap... The second is that it appears aftermarket miter gauges aren't all cut (sic) out to what they should be.

So, I've started my sled for my hybrid saw. Got the base with two runners made out of hardwood, and so far it's tight. Of course, after trashing the first attempt!

So the question:

how can I cut the miter sled fence to make it accurate, if the tool I'm using to make the fence is grossly in-accurate?

I have my Starrett combo, and my Incra guaranteed 45, and my Festool MFT with TS55. What I don't have is an engineer or drafting triangle. Lowes and HD don't carry these.

http://i269.photobucket.com/albums/jj44/BigMike1911/IMG_0002.jpg

The small triangle was large once, but dozens of attempts at readjusting the stock miter gauge to 45s with has made it this size. I'm about needing to empty my dust collector bag!!

Any help for this noob would be greatly appreciated!!

TIA,
Mike in Denver

[Tom Henderson2]

Hi Mike-

Well, you can always buy a drafting triangle online. Not expensive.

OR -- take your Starrett square to the borg and find a sheet of MDF that has a square corner. Cut that off and you have what you need.

But you have probably already thought of these...

-TH

[Colin Giersberg]

Go to Staples, Office Depot, Office Max, or Hobby Lobby. They all should have draftsman's triangles. In fact, Hobby Lobby may have the better selection, but then, you nevert know. By the way, get the acrylic ones. They seem to be a lot better than the styrene ones. I have used both types in drafting, and the styrene triangles get scratched up real bad, while the acrylic ones seem to be more scratch resistant and are harder to accidentally break them.

Regards, Colin

[Lee Schierer]

The trick with a miter sled is not that each side is exactly at 45, but that the total angle is exactly 90 degrees. I used a drafting triangle to set the one side to 45 degree angle to the saw kerf and then used my carpenter square to get the second side at 90.

Then when you go to cut angles that are going to fit together always cut one piece on the left and the other on the right side of the sled. The two will combine to make a 90 degree angle even if the initial 45 degree was off just a bit.

You might want to have higher walls on your sled to allow you to cut moldings and other parts that are taller than the 3/4" MDF that you are using to form the 90.

[Mike Shields]

[quote=Lee Schierer;888445]The trick with a miter sled is not that each side is exactly at 45, but that the total angle is exactly 90 degrees. I used a drafting triangle to set the one side to 45 degree angle to the saw kerf and then used my carpenter square to get the second side at 90. [quote]

Drafting triangle seems to be the consensus.

I remember being told mixing can result in a terrible hangover...err...

Why would you not use the drafting triangle (d.t.) to set the second leg? If the d.t. is accurate, why not stay with the same measuring instrument? If I'm not mistaken, the d.t. should have a 90 deg side!

Roger that on the higher than 3/4 fence.

Mike (newb) in Denver
(orig from Greensburg, PA)

[Cary Swoveland]

Mike,

I know you said you wanted to build your own, but if you have second throughts, you might want to consider Jointech's SmartMiter Sled, which is on sale now for $199. I recently bought one and am very impressed. It has several cool features, is well-made and is very accurate. There are a couple of good videos about it at http://www.jointech.com/smart_miter.htm . (I think the first is mainly about installation, so you might just skip to the second.) There are several accessories available. The only one I got was the hold-down clamp. I found the toggle clamp too lightweight, so I've used the bracket with a beefier toggle clamp that I had.

Cary

[Nissim Avrahami]

Hi Mike

As for the sled and the fence have a look here
http://www.sawmillcreek.org/showthread.php?t=64448

As for the method of cutting 45° frame members have a look here
http://www.sawmillcreek.org/showthread.php?t=64448

Wow, it was my first post in SMC...

niki

[Charles Lent]

Mike,

The real secret to getting 90 degree corners is to make the cut on the left piece as close to 45 degrees as you can and then make a cut on the right piece to match it. Having a miter sled with the 45 left and 45 right cutting positions lets you cut one piece on the left and the other on the right. Any variation in the angle of the saw cut on the left part is compensated for by the cut of the right part, so they will always fit together at 90 degrees. The accuracy is in the fixture and not in the saw cutting. In fact, the saw blade can be out of alignment with the fixture by several degrees and the two pieces that you cut with this fixture will still fit together at a perfect 90 degree angle.

Does this make sense?

Charley

[Alan Schwabacher]

Use a piece of 3/4" plywood to carry out the 5-cut method to precisely align your crosscut fence square to the blade. Once it is aligned, clamp on a stop block, and cut the plywood into a square (meaning all sides the same length, not just the angle.) Now place this very precise square of plywood on a crosscut sled, positioned diagonally so the leading and following corners are set exactly on one edge of the kerf cut into the sled. This gives you an extremely accurate right angle quite precisely divided in the middle. Use one side of the square as a fence for cutting one side of the miter, and the other side for cutting the other.

If you are unfamiliar with the 5-cut method, look here: http://www.thewoodshop.20m.com/five_cut_method_swf.htm

[Lee Schierer]

Why would you not use the drafting triangle (d.t.) to set the second leg? If the d.t. is accurate, why not stay with the same measuring instrument? If I'm not mistaken, the d.t. should have a 90 deg side!


The carpenters square gives you an inside 90 to work with. You can set it against the first piece and touch the second side to it. The longer legs on the square give you more accuracy as long as you know yoursquare is square, which mine is.