A Purpose-Built Measuring Tool

[Blue Chips]

Just a little purpose-built project.

I'm in the process of installing roughly 250 short lengths of tongue-and-groove boards between the ceiling joists/beams in the old house that my wife and I are restoring. There will be fiberglass insulation between the T&G boards and the underside of the attic floor boards. Additional insulation may be added in the attic later on.

Each T&G board has to be measured individually because the beams are hand-hewn (over 200 years old) and vary dimensionally, and we want to get a snug fit against the beams for a clean and rustic Federal-period farmhouse appearance while eliminating the need for a molding strip to cover the ends of the boards, which will also leave as much of each beam exposed as possible for aesthetic reasons.

There were three prerequisites: 1. The measurements need to be accurate; 2. Measurements must be made exactly perpendicular to the beams for best accuracy; 3. Measurements need to be quick and easy to transfer to the boards to be cut.

Getting accurate inside measurements with a tape measure can be done, but the tape must be held exactly perpendicular to the beam for accuracy, which isn't always easy to do. Also, measurements from a tape would need to be committed to my short-term memory (or written down), and then transferred to the boards to be cut, which introduces the possibility of adding to any measuring error.

(BTW, I have a laser distance measuring device that is supposed to give +/- 1/16” accuracy, with increments of 1/32”, but I’ve found that it can vary a little with factors like reflectivity, temperature, small dimples/nail holes, etc., and there is still the need to make sure that it’s aimed exactly perpendicular to the beam.)

Okay, TBH, I was actually just looking for an excuse to play in the shop and make a tool, so I fabbed up a purpose-built measuring tool that will provide quick, accurate measurements taken perpendicular to the beam and make it easy to quickly and directly transfer the measurement to each piece of wood without significantly compounding any error. I’m sure it’s not a new idea, but it was a fun little project and an excuse to dust off my mill.

First, I milled a couple of small stainless plates on my Bridgeport:





Then I drilled mounting holes, welded a couple of nuts onto the plates, mounted the plates on a 2-inch-wide rule, and installed a retractable spring-loaded drag and a locking screw (both with nylon tips). I also chamfered the edges a bit to avoid sharp edges. As you can see, the black L-shaped rule that slides in and out of the the longer rule makes it easy to take a measurement perpendicular to the beam.





All I do is add the extended distance to the 24-inch length of the larger rule, or even better, I can simply lock the length with the locking knob and transfer the length directly to the board for cutting…no need to even note or remember the measurement.

Here’s a demonstration of measuring between the beams with my gadget. Note the hand-hewn surfaces of the beams. FYI, the beams average anywhere between 7.5" x 7.5" and 8" x 8" and are about 16 feet long.



Work in progress. We've installed about 2/3 of the boards between the beams so far, but it won't be finished for a while, as I've temporarily shifted to a couple of higher-priority tasks in the house renovation work.



If I want to use this gadget for longer inside measurements later on, I can remove the small L-shaped black rule and install a longer 1-1/2-inch-wide rule.

 

[MadeByMiller]

Well done! Great solution, implementation, and the result speaks for itself.

 

[txvwnut]

Very nice on both projects.

 

[kyrbz]

I usually refer to these type of devices as "story sticks". That's one nice story stick

 

[stinkity stoink]

very clever, nicely done a!!

 

[Blue Chips]

Thanks @MadeByMiller, @txvwnut, @kyrbz.

I usually refer to these type of devices as "story sticks". That's one nice story stick

Thanks, and yes, I think it could be considered a variation on a story stick. I have a friend who uses a story stick to set up his table saw fence-to-blade distance, among other tasks.

 

[Sumboodie]

Without some room for expansion, how is that going to work out when it swells from humidity this summer?

 

[Blue Chips]

Without some room for expansion, how is that going to work out when it swells from humidity this summer?

It's a good question, and I would say that there won't be any problem at all with expansion.

• First, boards expand and contract very little lengthwise (with the grain) as compared to across the grain (which the tongue-and-groove joints will take care of).
• Second, there's roughly an average of about 1/32" gap between the ends of the boards and the beams, which is due primarily to the rough surface of the beams, so the gap probably ranges from 0 gap to a maximum of about 1/16" gap.
• Third, before installing, the boards were acclimated inside the house for a few weeks at a relative humidity of roughly 60-65%, which is above the mid-point in terms of the expected min-max RH range inside the house, so there shouldn't be much expansion at all, even across the grain of the boards.
• Fourth, all of the ends of the boards were cut an an angle to facilitate installation, so at any spots where the boards may actually be in direct contact with the beams, the contact area is only a hairline or a point, which is easily able to crush a bit (or push slightly into the beam) to absorb any small amount of expansion. Here's a cross-section of how the boards were cut (not to scale), showing how little of the end of a board might actually be contacting a beam.

I've seen the same approach used in other antique homes with no issue.