Wooden Straightedge

[Tom Winship]

When I was a kid, my dad made a straightedge that was about 5 of 6 inches wide x 3/4 thick x about 6' long (at least to a 3' kid it looked 6' long.
He built it by laminating a strip of oak (about 3/4 squared) on the outside of some other wood. I'm sure he used the main wood for stability and the oak for wear/hardness. He had cut a hand hold on the center piece.
Any suggestions on what the center piece of wood was?

[Jim Koepke]

Was it a dark wood or a light wood?

jtk

[Tom Winship]

Jim, it was a dark wood as I recall. Maybe even cherry, although he probably didn't have the money for that. I think I'm going to make one from plywood with an oak edge.

[Jamie Buxton]

Did you grow up in Texas? Then it might have been mesquite, which is a Texas native. Mesquite is dark, and it is amazingly stable with respect to humidity changes. If you make a straightedge with it, it should stay straight.

[Tom Winship]

Jamie, yes I did grow up in Texas, however back in the day, mesquite (at least north of Houston) was a pesky weed that we had only heard of. I have worked extensively with mesquite in the last 3 years and you are right, it is amazinly stable. It is hard to find a piece that long that would not have cracks in it. At least from my sources.
The mesquite that furniture is built from comes from south of San Antonio. That is where the "big stuff" grows. Here in central Texas it only gets to maybe 6-10" in diameter.

[John Coloccia]

Honduran Mahogany would be an excellent choice (also called South American mahogany, Geniune Mahogany etc..: swietenia macrophylla is the stuff).

If you're going to use fake wood anyway, though, I'd probably use MDF over plywood.

[Chris Fournier]

I'd be concerned about straight grain with as little runout as possible. any of the species taht the patternmakers preferred would be good with the exception if pine.

I have an 8' MDF ripping that I use.

[Kent A Bathurst]

If you're going to use something more stable than solid wood anyway, though, I'd probably use MDF over plywood.


Corrected for you, John.............:D

[Bob Strawn]

When I was a kid, my dad made a straightedge that was about 5 of 6 inches wide x 3/4 thick x about 6' long (at least to a 3' kid it looked 6' long.
He built it by laminating a strip of oak (about 3/4 squared) on the outside of some other wood. I'm sure he used the main wood for stability and the oak for wear/hardness. He had cut a hand hold on the center piece.
Any suggestions on what the center piece of wood was?

There would be no need for the oak, if mesquite was used, unless he planned to replace the face on occasion. My own guess would be Philippine mahogany for the body. Back in the mid 70's lauan or Philippine mahogany was the fancy dark wood available at a lot of lumber yards in Texas. It is fairly stable, nice enough for carving, but not hard enough for a straight edge without some facing. Honduran mahogany would be superior, but in Texas cheap substitutes have, at least in my lifetime, been more available.

Bob

[george wilson]

A carpentry book printed in the early 20th.C. advises: Never guarantee an oak door. I concur fully with that,having had experience with trying to keep oak from moving. I had to make a replica of an 18th.C. Kirkman harpsichord when I first came to Williamsburg in 1970. Many English harpsichords were oak veneered with mahogany. I had no long stored oak,so I bought several wide quarter sawn white oak planks,kiln dried,and kept them in the shop for several months while I made other instruments needed by the museum. Those planks kept changing shape for months,bowing one way,then the other,turning into S shapes,everything they could do. I became afraid to use them on the important,and LONG project of making the harpsichord completely from scratch. I ended up making the case out of mahogany,and veneering it with crotch mahogany panels and darker mahogany cross banding. It is still in service today.

Certainly,I'd never advise using oak on a straight edge. Eventually,in 1982,I used the oak planks to build the body for the 18th.C. fire engine,which was a less fussy project in terms of retaining nice joints.

[Leigh Betsch]

What do they make wood levels out of?
(I'd just use O1, or A2, or D2 or M2 or M4 or CPM3V ...)

[Kent A Bathurst]

....I'd just use O1, or A2, or D2 or M2 or M4 or CPM3V ...

OK, Leigh - now you owe me one bottle of Sierra Nevada Pale Ale - and a bunch of paper towels. Monitor and keyboard seem to be fine, though. :D :D

[Frank Drew]

If it's to be out of wood, I'd agree with Chris' suggestion of well-aged, straight-grained Genuine Mahogany.

[John Coloccia]

Corrected for you, John.............:D

Actually, I agree with you that MDF is superior and most of my jigs are made out of MDF. I meant more that if he's already decided that it didn't need to be made from a chunk of wood, MDF was a good choice...

...or fake wood, as I like to call it :)

For whatever reason, I have trouble with plywood warping, doesn't matter if it's Baltic birch or not. The Mahogany and MDF stay very straight in my shop, but my plywood is pretty unreliable. I couldn't tell you why.

[Pam Niedermayer]

Some years ago I bought a steel ruler encased in wood (maybe padouk) made by Steve Knight. The wood warped the steel, routinely. It wasn't really Steve's fault, but the only solutions were to decase the steel or hang the whole thing from a nail so it could work itself out.

I've also got a couple of maple winding sticks made by Blauvelt which seem to maintain their straightness without any problems.

However, if I were buying anything today, I'd stick with metal, aluminum, the like.

Pam

[george wilson]

The choice of wood in itself does not guarantee that it will stay straight. If the wood came out of a curved tree,etc. no telling what it can do. Also,improperly kiln dried wood can make trouble.

Even metal can be different in exactly the same alloys. It can be a little like wood on a smaller scale of "problematic". When they make replacement ribs for aircraft wings out of aluminum down at NASA,they take a billet,and cut the ribs for opposite wings out side by side from the billet to ensure as much as possible that the density of the metal is the same. They never just cut ribs out of plate aluminum.

Why would they be making aircraft parts? Some military planes are still being used way beyond their expected life,and parts are no longer available. Some planes served for over 30 years,like the A6 Intruder. How old are B-52's? Plus,they do a lot of experimental stuff not related to rockets.

This wouldn't noticeably effect a woodworking straight edge,but it is important in critical use situations,and in areas where a few thousanths of an inch of movement or distortion are important.

[Pat Barry]

I bet it was plywood. Don't laugh - it will stay straight unlike everything else.

[george wilson]

Plywood will stay straight? Do you include the Chinese stuff?

[Zahid Naqvi]

not to hijack the original post, but what is a good option for a straight edge say 24-36" long without going to the precision ground products offered for three figure costs. Granted we are talking woodworking and not a machine shop, there is a certain degree of tolerance that is acceptable.

[Erik France]

Zahid, There was a recent thread that has a little info on what you were looking for: http://www.sawmillcreek.org/showthread.php?166256-Straight-Edge

[Zahid Naqvi]

Erik, thanks those are some good options. As I am almost powerless (neander) I really don't need anything that precise to setup jointers and such.I was thinking something I could use to verify the flatness of a board or a surface I am flattening etc.

[Mel Miller]

What do they make wood levels out of?


Wood levels were usually made out of cherry, mahogany or rosewood.

Mel

[Bob Strawn]

not to hijack the original post, but what is a good option for a straight edge say 24-36" long without going to the precision ground products offered for three figure costs. Granted we are talking woodworking and not a machine shop, there is a certain degree of tolerance that is acceptable.

I have been very happy with this source for aluminum (https://www.midweststeelsupply.com/store/6063structuralangle) and other metals. Extruded Aluminum Architectural Angles are usually, (sadly not always) as straight as you can measure. For a simple straight edge, guide, winding stick and general reference, a few of these can be a very good tool to have at hand.

My own advice would be to buy about 4 or so, so they reinforce themselves a bit in the package, and so you can compare them to each other for perfection. The less perfect ones, if there are any, get used to make shorter sections, dovetail guides, saddle squares and the like. A few lengths of 2"x2" 1/4" thick and a length of 3"x3" 1/4" thick, would be a good start. The 3/8" thick is still good and solid, but I prefer the nice hefty 1/4" thick.

Bob

[Zahid Naqvi]

how about the 1/4"X2" 6061 aluminum bar (https://www.midweststeelsupply.com/store/6061Aluminumflat) 6 ft. at only $17.29, I can cut it to make two 3' winding sticks/straight edge. I have a 48" long granite slab that I use for flattening handplanes and such. I can use that to make any minor corrections if any.

[David Keller NC]

how about the 1/4"X2" 6061 aluminum bar (https://www.midweststeelsupply.com/store/6061Aluminumflat) 6 ft. at only $17.29, I can cut it to make two 3' winding sticks/straight edge. I have a 48" long granite slab that I use for flattening handplanes and such. I can use that to make any minor corrections if any.

That would certainly work, as long as you're not using it to set up machines where tolerances to about 5 thousandths or better are needed. If you prefer traditional materials, you might want to search Chris Schwarz's blog - I seem to remember him writing a few posts about recommended species, grain orientation, and geometry.

[Russell Sansom]

A few months ago I made 3 wooden straightedges 5.25 feet long, straight to .002". It's a fussy procedure, but as an interesting boot-strap sort of project that I found stimulating and very rewarding. I quickly set up my DJ-20 jointer with them and started writing an article for SMC. The article's done, but the final revision and publication were interrupted by a month-long vacation. I wanted to have the time to enjoy what I imagined would be a lively discussion.

It's a little out of the box...the box being "what wood can I used in a straightedge that will stay straight." My solution was to make three very straight lengths of wood, use them very quickly before they go to heck, and plan to redo the procedure again when they are needed.

As soon as I recover from this wicked jet lag, I'll post my article.

[Jim Rather]

Tom
I have an eight foot wooden straightedge that has served me very well for over thirty years. It is made of very consistant straight grain fir, 3/4" by 5". I curved the back as in old books I have seen which is supposed, according to old timers help the stability. There is a handhold in the center. In all this time I have only had to clean up the true edge a couple of times. Hope you have as good luck as I have had. Jim

[Ron Kanter]

In Jim Tolpin's recent book, The New Traditional Woodworker, he has a detailed "Shop Project" on building a wooden straight edge. He suggestion is to use "less dense species such as cherry or walnut (because) they are less likely to change shape with changes in ambient moisture levels."
Excellent book with lots of good information on working with hand tools.

[Russell Sansom]

I don't have access to Tolpin's book. Does he detail how to get the edge straight?