Replies

1. 
   johnhardy | Nov 08, 2002 03:19am | #1

   It's hard to tell from your request what you're cutting, but let's assume you're cutting something that is at least 4 to 4 inches wide (perhaps some sort of molding).

   What you could do is cut two pieces and put them together to form what you think is a 90 degree angle (corner). You could check this with a carpenter's square, or you could check it with the corner of a piece of plywood or hardboard. Or, you could even do the following:

   Cut 4 pieces and put two of them together to make one corner, and the other two to make another corner. stand them up on a flat table so that the vertical pieces adjoin. If there is a gap between them you'll know if your "90 degree" corners are off, and which way they are off. You could sneak up on an exact 45 degree cut this way without any measuring tools whatsoever.

1. 
   HONewbie | Nov 08, 2002 04:52pm | #4

   I'm not trying to cut anything specifically, just trying to verify my miter stops so that I'll know my cuts are on.  Plus it's sort of a thinking exercise.  I am assuming that none of my squares are 100% reliable, which is a pretty good assumption considering the amount of money I have spent on them.

   Fred, let me ask you this.  Is there a way to verify 45 degrees without having two perfectly parallel sides?  Can you do it just based on one straight reference edge?

   Thanks for the input

1. 
   johnhardy | Nov 08, 2002 08:01pm | #5

   Try this other method.

   I'm assuming you have two boards about 4 inches wide. Joint a straight edge on each. But a 45 degree angle on the end of each board, with the jointed edge against the saw and the jointed edge being the longer edge of the result.

   Place a straight edge on your workbench on top of a piece of paper about 2 feet square. On top of the paper, put the two pieces in a 90 degree corner and abut to the straight edge. Draw a line on the paper (which will be pretty much perpendicular to the straight edge.

   Now flip the two pieces so that the angle is on the other side, and put the edge about 1/4 inch away from the pencil line. Draw another pencil line. If the two lines are perpendicular, you've got a 45 degree miter cut on each board. It not, sneak up on the angle until it's accurate.

2. 
   mike4244 | Nov 09, 2002 02:46am | #6

   Bart, all the suggestions previously are good ones, I would like to add a simple tip.

   Place miter gauge upside down in the slot , adjust the protractor head against the saw table and tighten the head. This will give you a true 90 degrees. This cannot be done with some saws because the fence rail prevents it. I made a jig out of MDF board with 90 / 45/ 22 1/2  degree slots.The jig is a little narrower than the length of the bar so the T-slot washer does not interfere.I used a drafting triangle for a guide for the router. The slots are 3/8" deep.This jig will give you quick and accurate repeatability.

2. 
   fredsmart48 | Nov 08, 2002 02:48pm | #2

   First you can’t use your framing square that is not square from the company most of the time. It is square enough for framing not cabinet work.  Play wood and hard board are not always square either

   If you want to check your saw for 45 degree cuts this is how.

   You need to joint two 4" board so they are straight

   Next you need to plane them so they are the same width and have parallel sided

   Next cut two ends to 45 degrees on the saw you want to check.

   You need a straight edge the jointer will do, lay them end to end so they from one straight board 45 should touch all the way along the angle. If there is a gap at the bottom or top it is not a 45 degree miter.

   
   

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   Edited 11/8/2002 7:05:53 AM ET by fredsmart

3. 
   fredsmart48 | Nov 08, 2002 03:52pm | #3

   Do you want to check your framing square for square? it is easy also.

   First you need a straight piece of board that is 4 foot by 12 inches is good 16 inches is better.

   Next run it on a jointer to get a very straight edge.

   Next but the 24" part of the square along the straight edge. the 16 leg of the square in the middle of the wood. The easiest way is to get some one to help. On the straight edge clamp two small pieces of wood stick up and then pull the square against the to sticks.

   Next draw a line along the 16" part of the square. make sure you use a sharp pencil or a making knife..

   Next flip the square over and do it from the other end board.

   Now the two lines should be parallel to each other. If not the square is not square.