Preferred base for jigs

[David Ragan]

Do most of you all prefer 3/4 MDF, or a good grade of plywood for making your jigs?

I just hauled in a sheet of 3/4 MDF from BORG Saturday, I thought, I'm getting too old for this. Too heavy.

I know that MDF holds it's shape so well ("dimensional stability"?), doesn't chip out--but doesn't like any water on it. And, prefers T-Nut instead of a regular screw in it, right?

Down side to a high grade of plywood is...not all that much lighter, and may chip out(?) But T-nuts not necessary for holding fixtures in place.....

Seems like most of those cool jigs that go over the rip fence are MDF.

Anything I miss here?

Am thinking of building the outfold extension table next week, or the drill-press table while I'm off work. (my activity on this site will spike then, I'm sure;))

[glenn bradley]

MDF is handy to have around for the reasons you state. For jigs that are to last awhile (generally my second version of something) I move to BB ply (BB/BB grade or better). For any wide surface that needs to be self supporting to much extent I also shy away from MDF. That being said, my 4 ply MDF workbench and 1-1/8" thick MDF router table are doing fine. Both are very well supported across the spans but, this does lead to a lot of weight; which is not real suitable in jigs.

[Bill Adamsen]

Nothing beats BB ... any scraps seem to immediately disappear into a jig.

[Mike Cutler]

If it's a limited use jig, MDF is fine. If it's something I know I'll use a many times and want to keep around, then it's either Lexan, or Baltic birch.

Unless you have a climate controlled shop, I'd tend to argue against that Drill Press table being made of MDF. It will eventually sag, and so will an out feed table.( Mine were very well supported underneath also.) My shop is not climate controlled and any MDF type "support jigs" have long since made it to the dump. My drill press table and router table are made of BB and they've been fine for over a decade.

[roger wiegand]

Another vote for baltic birch or its American relatives for anything I want to keep for a while. I do use MDF for one-time jigs and bending forms, though I hate lifting it or cutting it.

[Roy Harding]

Another vote for baltic birch or its American relatives for anything I want to keep for a while. I do use MDF for one-time jigs and bending forms, though I hate lifting it or cutting it.

What he said.

[pat warner]

Aluminum. (http://patwarner.com/images/new_router_table2.jpg) Threads well, won't bend nor change shape like MDF, sucks up vibration, water proof, and
jig plate is ground flat and is of uniform thickness.

[Keith Hankins]

I hear ya man on the weight. My boys are grown now and gone. I'm a doit my self or not at all now. You have several options is get them to cut it for you and do the two piece dance. Baltic birch is nice but expensive.

I'll reccomend for moving sheets around the gorilla grip. I got one because my shop is in my basement so I have to get it out and down 6 steps from the outside of the house.

http://www.amazon.com/Gorilla-Gripper-44010-Panel-Carrier/dp/B0007TYCA8

Talk about helping me get stuff around. Great leverage and it won't mar the sheet goods.

[Brian W Smith]

Probably shouldn't respond....oh well,colour me stupid.

If we can't "weld it or tap it".....what's the point?And even that is with serious reservations.

[Robert Payne]

Almost all of my jigs are made with 1/2" Baltic Birch -- flat and stable and edges can be rounded over for splinter-free use.

[Prashun Patel]

Glib answer alert: it matters what jig you are talking about. For a sacrifical fence or an auxiliary miter fence i think its nice. But for the base of a sled its heavy and you lose a critical 3/4" blade height. For sleds i actually prefer 1/2" or even 1/4" mdf or hardboard.

[Jim Dwight]

I think the biggest advantage of MDF is it has a nice smooth flat surface. Disadvantages include sagging, weight, extremely nasty dust, and doesn't take fasteners well. I avoid it. When I want a smooth flat surface, like for an extension table, I use melamine particle board. It isn't as strong as plywood but it's stronger and smoother and more durable than MDF. For most jigs, I use scrap plywood.

[Robert Parent]

I prefer baltic birch for anything that I want to last. I really don't like MDF as it creates lots of fine dust and found it to change size greatly as the humidity changes. About the only place I use MDF is for the spoil board on the CNC router as it's cheap and can be easily surfaced before each major project.

Robert

[ian maybury]

Another that generally avoids MDF. Just watch out for ordinary commercial grade construction ply - short of buying Finnish or a graded birch ply the quality has nose dived in recent years. There's often lots of warps, built in stresses caused by laminating defects, thickness variation and pulpy inner layers so that the rigidity is very poor. There's even junk birch ply about here now that's as bad as any construction ply. Even fancier stuff like pehnolic coated ply can be very rough unless the right grade is specified.

MDF isn't that much different depending on where you buy. The box store stuff we get is often low rigidity (cardboard masquerading as a structural board), less accurate and doesn't machine very well. There's very nice stuff indeed like Valchromat (an architectural variety of high grade MDF from Portugal) about too, but it costs...

The problem here is that most places don't carry the choice of grades, just the junk. So it can get in special orders, minimum quantities and the like. Doesn't seem to be such an issue in the US, near large population centres anyway...

[Bill White]

Use the all weather MDF for stability and moisture issues. I have used the Xtera brand with good results. No connection otherwise.
Bill

[Von Bickley]

I would use Baltic birch. Never had any MDF in my shop and not making any plans to get any. I don't want to work with compressed saw dust / cardboard.

[David Ragan]

Aluminum. (http://patwarner.com/images/new_router_table2.jpg) Threads well, won't bend nor change shape like MDF, sucks up vibration, water proof, and
jig plate is ground flat and is of uniform thickness.

Sounds expensive....where you get?

[Greg Hines, MD]

If I were making a drill press table or something I want to keep around a long time, I would use Phenolic coated plywood to keep it easy to move and durable. That said, my table saw sled is made of 1/2" MDF and is probably 10 years old, and has still worked fine.

Doc

[pat warner]

Metal supply houses. Cut offs ~$2.79/pound here in San Diego CA. Use it once & your precision and accuracy increase x 10.

[Garth Snyder]

...I would use Phenolic coated plywood to keep it easy to move and durable.
Another great option along these lines is MDO, which is a resin-paper bonded plywood. All the structural advantages of plywood with a surface even flatter than MDF. I haven't used phenolic plywood, but I would imagine it's very similar in these respects.

[Dave Cav]

Another great option along these lines is MDO, which is a resin-paper bonded plywood. All the structural advantages of plywood with a surface even flatter than MDF. I haven't used phenolic plywood, but I would imagine it's very similar in these respects.

Here's a second vote for MDO board. You're not going to find it at the BORG, though. You need to go to a commercial lumber yard that sells to the trade.

[John Lankers]

I don't think I've built any jigs from anything but BB yet, but I have some left over 5/8 MDF Superlite around and when soaked in Polyurethane it's durable - why not, it's cheap.

[Greg Hines, MD]

Here's a second vote for MDO board. You're not going to find it at the BORG, though. You need to go to a commercial lumber yard that sells to the trade.

At my lumber yard, they call it Sign-Makers Plywood, and it is also very handy to have for jigs.

Doc

[Jeff Duncan]

I prefer mdf for the great majority of jigs I build. It's greatest attribute is that it's flat, which your not going to get with any plywood….even baltic. It does hold screws into the face just fine, it's the edge screws you have to be careful with. Even on my shaper jigs the DeStaco clamps that hold the work down are secured by regular wood screws and haven't had any problems. As far as dimensional changes with humidity…..that would have to be a really large humidity swing to noticably change the size of an mdf panel:eek: Keep in mind everything you see for flat panels in the commercial world is likely to be mdf, from high end conference tables, to elevator panels, to hotel lobbies. So the idea that it's going to start moving significantly due to a humidity swing is just not accurate.

The stuff is really almost perfect for jigs as it's easy to machine with the most basic tools and holds up very well over time. Many of my hinge jigs and shaper jigs are well over a decade old and still as accurate as when they were made. Aluminum and/or Plastics would be good for jigs as well, but they're heavier, harder to machine, and honestly a bit overkill for anything but really high production use. The weight of full sheets is a PITA to deal with, and you can get around it a bit by going with Ultralight…..but for jigs I still prefer the heavier denser stuff.

good luck,
JeffD

[Dave Lehnert]

What does a sheet of Medium Density Overlay cost ?

[Rollie Kelly]

At Menards, who stock 1/2 & 3/4" MDO, 3/4 is ~$65 and 1/2 ~$5 less. Good stuff I like it a lot. I have a rain gauge mounted on unfinished MDO that has been exposed to the weather for 4 years. The only change has been fading of the top surface.
Rollie

[Malcolm Schweizer]

I am envious of all you guys with Baltic birch and MDF. I have to have that stuff special ordered. We are thinking about ordering a pallet for the shop to have on hand. I use the stuff HD sells that is prelaminated with white "Formica-looking-stuff." It makes nice jigs that last forever and the white gives them a clean look, but moreover it makes it easy to see what you are doing and gives you a good place to pencil in notes or make tick marks.

[Garth Snyder]

What does a sheet of Medium Density Overlay cost ?
Here in Seattle, a 4' x 8' sheet of 3/4" MDO runs about $80.

[Erik Christensen]

MDF vs BB for jigs - depends on what the jig is for (and often what is on hand in the scrap box).

if I have a choice, i pick the material best suited for the type of jig - if flatness matters but structural strength does not (like a shooting board) MDF is a better choice, also it is easier to finish shape - all my patterns for the shaper are MDF - I find it much easier to get a perfectly smooth fair curve in 3/4" MDF than BB.

I have yet to buy any material just to make a jig - in the end the jig is made from what is on hand :)