The Corners Don't Fit

WmZiggy · Post by **WmZiggy** » Thu Feb 20, 2014 4:31 pm

Some years ago I built a miter jack. Works really well with a well tuned plane. If your saw blade is close, this will zero it in to 45 degrees.

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Fred Grover · Post by **Fred Grover** » Thu Feb 20, 2014 5:03 pm

That is nice WimZiggy. I would like to see that in use. By chance do you have plans for that ? I like to try and make my own Jigs if it is safe and can save money in my book that is the way to go. But, sometimes you cannot skimp on certain items. Thanks for sharing that with us.

terrydowning · Post by **terrydowning** » Thu Feb 20, 2014 6:34 pm

Miter Jack is on my long list. One of these days.

shipwright · Post by **shipwright** » Fri Feb 21, 2014 12:47 am

+1 for the miter jack. Here's a link to the one I made recently.
Here's a link to the plans from Shop Notes.
BTW, the donkey's ear plan on the same Shop Notes link is a great way to get perfect miters on longer edges.

Fred Grover · Post by **Fred Grover** » Fri Feb 21, 2014 12:59 am

Thanks for sharing this with us Paul.

dusty · Post by **dusty** » Fri Feb 21, 2014 6:41 am

algale wrote:Wonder how many thousandths of an inch that 0.2 degree error amounts to per cut.

Some would consider it close enough.

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reible · Post by **reible** » Fri Feb 21, 2014 6:46 am

One could call that a hairline, seeing as that is what it is.

Ed

dusty wrote:Some would consider it close enough.

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BuckeyeDennis · Post by **BuckeyeDennis** » Fri Feb 21, 2014 6:56 am

dusty wrote:Some would consider it close enough.

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Are you modelling a 0.2 degree total error there? I thought that your original example had a 0.2 degree error per miter cut, giving a total error at the joint of 0.4 degrees.

dusty · Post by **dusty** » Fri Feb 21, 2014 8:32 am

The original post was the result of a .2° in each of eight miter cuts that would be required to form a box. The pieces were jointed together (in Sketchup), one corner at a time, forcing the error to accumulate at the last joint.

Purpose being to show that this is not the best way to fit together the pieces. Tiny error accumulates. This is a lesson that I learned recently while trying to build some items for one of the kids. These were items that I wanted to be as perfect as I could make them. I did not do so well.

I posted this image in response to a question from BuckeyeDennis. It only vaguely relates to the other images in this thread.

dusty · Post by **dusty** » Fri Feb 21, 2014 8:38 am

reible wrote:One could call that a hairline, seeing as that is what it is.

Ed

Yes, it is a small gap but if that gap was allowed to accumulate during a glue up, it could become very noticeable. Final assembly can be as important as the individual cuts.

In reality, many of our cutting errors seem to cancel one another out as we do the assembly. In fact, an experience wood worker probably utilizes that possibility in the process.

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The Corners Don't Fit

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