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squareness #1: Math doesn't add up

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Blog entry by JoshO posted 08-01-2009 12:37 AM 875 reads 0 times favorited 7 comments Add to Favorites Watch
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I just upgraded my craftsman fence to a Delta T2 system and the install went very well. The blade on this old machine is within .008 to the miter, and the fence is within .002 TIR to the miter which are both within reasonable limits for my projects and skill. But I noticed one thing – as I am ripping my birch ply workbench, the material as it approaches the end of the fence will be riding out almost 3/8 of an inch from the fence. I try to keep the sheet goods flat and square, but this seems to be on ongoing issue for me.
The funny thing is, after the cut is made, both the piece and the waste are square. The machined dimension is exactly where it needs to be and parallel to the face that was riding on the fence.

I know I should just be concerned with safety and end product quality, but it bugs me when I see something I can’t understand.

-- What do you mean it's square? How did that happen?



7 comments so far

View Sawdust2's profile

Sawdust2

1467 posts in 3550 days


#1 posted 08-01-2009 12:44 AM

When I took a course with Ian Kirby many years ago he commented that you did not need to be concerned with the board after it was past the blade so long as it was square when it went into the blade. In fact having the back of the fence be a little farther away from the blade was good.

Lee

-- No piece is cut too short. It was meant for a smaller project.

View Brad_Nailor's profile

Brad_Nailor

2539 posts in 3420 days


#2 posted 08-01-2009 12:54 AM

In fact some fence/saw manuals recommend that you skew the fence (not 3/8”!) slightly back to front to help prevent kickback…but you do sacrifice a slightly unsquare cut. I would rather square my fence dead on and use a riving knife or splitter…

-- http://www.facebook.com/pages/DSO-Designs/297237806954248

View JoshO's profile

JoshO

48 posts in 2863 days


#3 posted 08-01-2009 01:09 AM

A splitter is something I really need to be looking into. . . . for safety reasons anyway.

-- What do you mean it's square? How did that happen?

View matt garcia's profile

matt garcia

1877 posts in 3134 days


#4 posted 08-01-2009 01:15 AM

Your new fence is not square with the blade. You need to first get the blade square with the miter slots. Once that is done, then you can get the fence square with the miter slots. The miter slots are parallel with eachother, or should be. So those are your reference points. You square the blade, and the fence off of the slot, always. Hope that helps! FYI, this is a safety concern.

-- Matt Garcia Wannabe Period Furniture Maker, Houston TX

View a1Jim's profile

a1Jim

115202 posts in 3039 days


#5 posted 08-01-2009 05:30 AM

Check you fence from your miter slot.

-- http://artisticwoodstudio.com Custom furniture

View ajosephg's profile

ajosephg

1878 posts in 3023 days


#6 posted 08-01-2009 06:30 AM

Somethiing is seriously out of whack. Shouldn’t be hard to figure out with that much error.

-- Joe

View JoshO's profile

JoshO

48 posts in 2863 days


#7 posted 08-01-2009 07:12 AM

I’ll figure it out.

-- What do you mean it's square? How did that happen?

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