Logan 750-1: Use large carpenter square

Started Mar 27, 2013 | Discussions
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soloryb Senior Member • Posts: 2,127
Logan 750-1: Use large carpenter square

I just bought a Logan Simplex 750-1 and one of the first things I did was to check the squaring arm for 90 deg. I used a 6" X  8" drafting triangle and everything seemed to check out just fine. The squaring arm appeared to be at a perfect right angle to the guide rail, as it should be.

However, when I tried to square a 30" X 40" mat, I couldn't get the mat to be 90 deg. at every corner. I realized that my unit wasn't really squared even though my drafting triangle was telling me all was OK. Finally I used my 18" X 24" carpenter square to more accurately check things out. With the larger square I could just make out a tiny gap (I think less than 1/64") between the squaring arm and the tool at 24". The arm was out of square by so small an amount that it was only observable with the use of the larger carpenter square. I then adjusted the arm and squared several mats with no observable errors.

If you are following Logan's strong suggestion that you square your raw mats before doing anything else, it involves a cut followed by rotating the piece 4 times. If the Logan is even a smidgen out of square then this error is multiplied 4 times. In my case I ended up with a final cut that was between 1/16" and 1/8" off.

From now on I'll check the squareness of the Logan - before every job - with my large carpenter square. It's cheap insurance given the time I wasted and the price of mat boards.

Otherwise, this is one fantastic machine.

 soloryb's gear list:soloryb's gear list
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DotCom Editor Veteran Member • Posts: 6,791
Agreed

A large carpenter's framing square is the only way to go. Good luck with your Logan. I have the 60-inch Logan Framer's Edge and it works splendidly.

soloryb OP Senior Member • Posts: 2,127
Re: Agreed

DotCom Editor wrote:

A large carpenter's framing square is the only way to go. Good luck with your Logan. I have the 60-inch Logan Framer's Edge and it works splendidly.

I called Logan and asked them to include this in their manual. They just refer to using a carpenter's square with no reference to the necessary size to achieve accuracy.

 soloryb's gear list:soloryb's gear list
Fujifilm FinePix X100 Nikon D800E Nikon AF-S Nikkor 24-70mm f/2.8G ED Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II Nikon AF Fisheye-Nikkor 16mm f/2.8D +9 more
Oscar Rico
Oscar Rico Senior Member • Posts: 2,235
Re: Logan 750-1: Use large carpenter square

Not need carpenter square.

Mark same distance of each side say 20" inches.

Multiply one side say 20"x 1.414= 28.28"
28.28" is the exact distance between the ends of each side (across). (If not adjust accordingly).

You just saved the cost of the carpenter square. Regards: Oscar

Rkelac Regular Member • Posts: 466
Re: Logan 750-1: Use large carpenter square

Oscar Rico wrote:

Not need carpenter square.

Mark same distance of each side say 20" inches.

Multiply one side say 20"x 1.414= 28.28"
28.28" is the exact distance between the ends of each side (across). (If not adjust accordingly).

You just saved the cost of the carpenter square. Regards: Oscar

Hard to measure that exact. The rotating 90 degrees method showed my new 650 was perfectly square.

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Oscar Rico
Oscar Rico Senior Member • Posts: 2,235
Re: Logan 750-1: Use large carpenter square

If you cannot measure correctly, then you need to get the tool that does it for you. I personally have no problem, but that is me. Regards: Oscar

E Dinkla Contributing Member • Posts: 631
Re: Logan 750-1: Use large carpenter square

soloryb wrote:

If you are following Logan's strong suggestion that you square your raw mats before doing anything else, it involves a cut followed by rotating the piece 4 times. If the Logan is even a smidgen out of square then this error is multiplied 4 times. In my case I ended up with a final cut that was between 1/16" and 1/8" off.

The method in itself is not wrong but the assumption that the multiplication is 4x, it is only 3x.

Logan and Rotatrim make the same mistake or copy one another. See a similar thread here:

http://www.luminous-landscape.com/forum/index.php?topic=76727.0

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Met vriendelijke groet, Ernst
500+ inkjet paper white spectral plots: OBA content etc.
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm

just Tony Senior Member • Posts: 1,237
Perhaps this tool?

Oscar Rico wrote:

If you cannot measure correctly, then you need to get the tool that does it for you. I personally have no problem, but that is me. Regards: Oscar

But you could buy a lot of carpenter's squares with that much money; it's probably not what you had in mind to accomplish your implied accuracy of 0.01 inch:

http://www.globalindustrial.com/p/tools/test-measurement/calipers-dial/fowler-xtra-range-electronic-caliper-40-inch-range

just Tony Senior Member • Posts: 1,237
Don't forget to check the square

Here's a method but it only has a 2X error amplification:

http://www.newwoodworker.com/fxfrmsqr.html

E Dinkla Contributing Member • Posts: 631
Re: Logan 750-1: Use large carpenter square

Next to being inexpensive the sheet method represents actual practice so the result of the correction will apply better to practice. Select a sheet with a paper thickness that is about the average of the papers used.

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Met vriendelijke groet, Ernst
500+ inkjet paper white spectral plots: OBA content etc.
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm

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