Stable Wood For Flat Reference...

[Derek Arita]

Just watched Ng's video on making a sled and he used a flat chunk of maple as a flat reference for the glue up of his fence. I'd like to make a similar fence, 4"x6"x30, out of a stable wood, but one that is not as pricey as maple. Any suggestions?
How long do you think this hunk of wood will stay true once machined?

[glenn bradley]

I used straight grain fir and have only had to joint the fence once in several years.

[Dave Zellers]

Ash is very stable.

[Prashun Patel]

mdf or plywood would be meet the stability and price criteria (but not the pretty criteria so much).

Although, 4x6 is a mighty thick fence. Consider the weight.

[Derek Arita]

mdf or plywood would be meet the stability and price criteria (but not the pretty criteria so much).

Although, 4x6 is a mighty thick fence. Consider the weight.
Just to clarify, the 4x6x30 will be a reference slab to be used as a clamping base for gluing up 3 layers of 1/2" ply for sled fences. As I will be using the slab for present and future fences, I want it to hold it's flatness over time, as much as possible.

[Erik Christensen]

you want long term flat & stable nothing beats BB ply - I take scraps all the time - rip to common width & length - glue up & put into a vacuum bag on a flat platen - can make a slab as thick as you want but I have found that after 2 1/4" (3 layers of 3/4" ply) it is a waste of time making it thicker - i have not been able to deflect a 2 1/4" slab with any clamps i own

[Prashun Patel]

Then mdf seems like it'd be perfect. Sealed and waxed, it'll be a great clamping form.

[Peter Quinn]

Box beam made from plywood. Cheap and rigid, as accurate as you make it, build it off your jointer table or similar flat surface. That's been my approach for door stiles. Works well. Think small tortion box.

[Brian W Smith]

Your shop's "climate control" is going to be a huge factor....just sayin.Then,to a slightly lessor degree how you finish the pce.And "finish" here isn't about any clear coats,although this is a factor.It's about how you go about surfacing the pce.There are marked differences when comparing a planed surface vs scraped....and if "grinding"(sanding to some)...what grit.It's how the surface finish reacts to your shops range of humidity.....and how much "stress" is involved with attaining that particular finish.Which is why sometimes grinding can be better than planing.Tough subject.

[Brian Tymchak]

Box beam made from plywood. Cheap and rigid, as accurate as you make it, build it off your jointer table or similar flat surface. That's been my approach for door stiles. Works well. Think small tortion box.

+1. I glued up the first pairs of laminates for my bench tops this way.

[Ole Anderson]

A granite or quartz countertop offcut from a large kitchen sink would trump any of the other suggestions as to being stable. At least you would start with a flat glue-up, no guarantee it would stay that way. Cheap if you can snag one from the fabricator. Otherwise I would go with 3/4" MDF, 2 layers sandwiched together with a third piece at least 4" wide with a very straight edge glued perpendicular to the other two to form a Tee or Angle.

[stan shields]

I just watched William Ng's sled video too and I have the same question. What are you using as a "Flat reference"? How about a 4" piece of square aluminum tubing?
Any other ideas?
How do they grind granite counter tops? Do you think those are really flat?

[Bill Dufour]

QS old growth redwood with no knots. AKA "clear heart" Can not buy big beams anymore will have to find used ones. Less weight then the other species mentioned here.

[Mel Fulks]

Check with a Restore . They often have granite and marble used counter splashes....for some reason it does not last as long in today's kitchens as laminate did. But might work for your fence.

[Andrew Seemann]

Nothing made of solid wood, especially a 4x6, will be completely stable. Some woods will be more stable than others: red oak, walnut, ash, white pine, basswood for example; and some are less stable than others: beech, birch, hard maple, can be challenging. The moisture content of the center of a 4x6 will probably be a season out of sync with the outside of the board, depending on the size of your seasonal variations.

For something that size, a box beam of baltic birch or fir core plywood will be much more stable than any solid wood. No thick center to be out of sync with humidity, but still quite strong. Not to mention much cheaper and easier to make.

[Mike Cutler]

Just watched Ng's video on making a sled and he used a flat chunk of maple as a flat reference for the glue up of his fence. I'd like to make a similar fence, 4"x6"x30, out of a stable wood, but one that is not as pricey as maple. Any suggestions?
How long do you think this hunk of wood will stay true once machined?

It will stay flat for a long time as long as the humidity doesn't swing all over the place. I imagine that William just makes a reference, as he needs one, from a scrap pile.
Wood wouldn't be my choice for a long term, known, flat reference standard. Building a box beam, as Peter detailed, would be my choice for a "longer term" standard.

[andrew whicker]

could someone show a photo of a plywood box beam workbench? I'm having a hard time picturing what you are describing.

[stan shields]

Went to a granite counter top shop today and bought a 6" X 30" X 1.25" backsplash cutoff for $40. Looks to be flat enuf for woodworking, my precision ground straightedge looks great on it.

[Bradley Gray]

I have a bench that I use for most of my glue-ups - laminated maple 2 1/4" x 12" x 8ft. It is mounted on cast iron legs intended for a lathe stand.
Once in 30+ years i thickness sanded and refinished it, mostly to get rid of glue residue.

374803

[Brian Tymchak]

I don't know that I would call it a workbench per se but I guess it could be. Here's the box beam I built to be a flat reference when I laminated pairs for my bench tops. 3/4" ply, 5" flange, 4" web, 8' long. I think that thing could hold up a vehicle. :)

PS: In hindsight, I didn't need 4" webbing. I could have done 2" and it would be just as good and likely easier to assemble.

[Jerry Wright]

Think bowling alley!

[Osvaldo Cristo]

My worst fear is when I die my wife will sell all my tools for what I told her I paid for them.

:D

[mike waters]

Melamine on mdf

[Tom Trees]

Find a fire door in a skip, I suggest looking around hotel renovations for a nice slim one.
Good luck