Dovetail Checking Square

[Jim Koepke]

Just for the fun of it some of the scrap from making a rosewood handle for dovetail saw is in the process of being used to make a small square for checking pins and tails for square.

A small piece of scrap rosewood was cut and then squared all around.

The hard part was finding something to use to make the blade. My first thought was to use a 0.040" feeler gauge. Then I remembered a piece of a ruler that came with a group of rulers purchased on ebay a few years ago. It was easy to mark with one of my gauges and cut with a hacksaw. It is kind of different ripping 0.031" steel with a hacksaw than it is to rip a piece of wood with a D8.

To clean up the edge a very shallow rabbet was cut on a piece of wood:

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Another piece of wood was placed on top of this and together it was all clamped up in a vise so it could be filed down smooth.

After fiddling with it to get it an even depth over its length a slot was cut, different saws were tried to find which one made the kerf to match the blade. Turns out it was the band saw.

After a bit of fiddling to get everything square it was glued with epoxy:

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One side is barely 3/4" and the other is not quite 1-1/2". This will work well with my most common sizes of stock.

After the glue dries overnight there will be some brass pins installed through the wood and blade for some added strength. Ace Hardware had some 1/2" brass strips that will be used on the bearing faces of the square. It will likely be a few days before much more can be done on this will post the next steps as they happen.

jtk

[Frederick Skelly]

That's nicely done Jim! Adding the brass will really dress it up. Look forward to seeing the finished product!

I made mine using 1/8" round brass rod for the blade and Purpleheart for the handle.

Fred

[Jim Koepke]

Learned a few things on this about mixing metal and wood in a project. Also learned to make the brass rod a bit longer when using brass rod for rivets. Too long can be dealt with. Too short leaves some of the cavity unfilled. Aside from that the order of the different steps would have likely been better if it was rearranged.

All in all though it will be a decent tool for a specific job. If another one is ever made, it will surely benefit from what was learned on this one.

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Here is is shown with the saw handle that had the left over scrap to make the square.

I will likely do a bit more work on the finger grip slots. They were bigger but lost a little area when the whole thing was worked on the belt sander.

jtk

[Derek Cohen]

Jim, that infilled look is outstanding. Are you able to adjust the arms for depth? That is important for half-blind dovetails or mortices. I can see you incorporating a set screw to hold the arm in place in a channel ... ?

Chris Vesper version of a small double square has options worth looking at for ideas ...

https://www.vespertools.com.au/vesper-squares/precision-double-squares/

Regards from Perth

Derek

[Tim Cooper Louisiana]

That looks really nice Jim!

[Jim Koepke]

Jim, that infilled look is outstanding. Are you able to adjust the arms for depth? That is important for half-blind dovetails or mortices. I can see you incorporating a set screw to hold the arm in place in a channel ... ?


That looks really nice Jim!

Derek, Tim, Thanks for the kind words.

Derek, this one is not adjustable. The short arm was planned be able to reach into my most common size of half blinds and full dovetails.

I have been thinking about making another with an adjustable arm since the left over half of the rule is still available. Have to give it a think for a while.

Thanks for the Vesper Tools link, it does have some ideas to think on.

jtk

[Pat Barry]

Nice project Jim. I take it you used belt sander to true up the sides. Did you have any issues with brass embedding in the wood?

[lowell holmes]

This is the square I use. It never occured to me to make one.:confused:

http://www.leevalley.com/us/wood/page.aspx?p=44279&cat=1,42936http://www.leevalley.com/us/wood/page.aspx?p=44279&cat=1,42936

[David Eisenhauer]

I like the finger grooves. cool.

[Jim Koepke]

Nice project Jim. I take it you used belt sander to true up the sides. Did you have any issues with brass I'm bedding in the wood?

The only problems were of my own making. The brass should have been cut and fitted before securing the blade. Though the assembly order was scrambled it still came out okay.

jtk

[Pat Barry]

The only problems were of my own making. The brass should have been cut and fitted before securing the blade. Though the assembly order was scrambled it still came out okay.

jtk
It would be difficult to keep everything planar by any other method than to sand it like you did after assembly. Hence my question about the brass embedding into the wood. Apparently this wasn't a problem for you. Good to hear it worked out ok.

[Jim Koepke]

It would be difficult to keep everything planar by any other method than to sand it like you did after assembly. Hence my question about the brass embedding into the wood. Apparently this wasn't a problem for you. Good to hear it worked out ok.

The top pieces, with the rivets to hold the blade, were set into cut laps. The side face pieces are on the surface and held in place by #4X1/2" screws. The hard part was to cut a slot to fit over the blade. My hacksaw blade is a touch narrower than the thickness of the blade. Used some sandpaper and a knife edge file to get the slot to fit over the blade.

jtk

[lowell holmes]

I use a starrett depth gage as a dovetail square. Try it, you might like it.

[Jim Koepke]

I use a starrett depth gage as a dovetail square. Try it, you might like it.

A quick look indicates the most economical model, #237, starts at ~$50. For that kind of money I would have bought the Lee Valley Small Double Square:

http://www.leevalley.com/us/wood/page.aspx?p=72730&cat=1,42936,42941&ap=1

In fact, it was seeing that in the Lee Valley catalog while walking back from the mail box that got me started on wanting something better than my nail in a block of wood gauge.

jtk