Page 1 of 2 12 LastLast
Results 1 to 15 of 29

Thread: Preferred base for jigs

  1. #1
    Join Date
    Sep 2007
    Location
    Atlanta, GA
    Posts
    1,356

    Preferred base for jigs

    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)
    David
    Confidence: That feeling you get before fully understanding a situation (Anonymous)

  2. #2
    Join Date
    Mar 2006
    Location
    SoCal
    Posts
    22,480
    Blog Entries
    1
    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.
    Last edited by glenn bradley; 05-11-2015 at 3:53 PM.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  3. #3
    Join Date
    Nov 2012
    Location
    Southwestern CT
    Posts
    1,392
    Nothing beats BB ... any scraps seem to immediately disappear into a jig.

  4. #4
    Join Date
    Feb 2003
    Location
    Griswold Connecticut
    Posts
    6,923
    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.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  5. #5
    Join Date
    Sep 2013
    Location
    Wayland, MA
    Posts
    3,651
    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.

  6. #6
    Join Date
    Mar 2007
    Location
    Terrace, BC
    Posts
    519
    Quote Originally Posted by roger wiegand View Post
    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.
    I love mankind. It's people I can't stand.

  7. #7
    Aluminum. 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.

  8. #8
    Join Date
    Oct 2007
    Location
    Pottstown PA
    Posts
    972
    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-Grippe.../dp/B0007TYCA8

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

  9. #9
    Join Date
    Sep 2012
    Location
    Mnts.of Va.
    Posts
    615
    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.

  10. #10
    Join Date
    Nov 2007
    Location
    Hendersonville, NC
    Posts
    331
    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.
    ______________________________
    Rob Payne -- McRabbet Woodworks

  11. #11
    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.

  12. #12
    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.

  13. #13
    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

  14. #14
    Join Date
    Aug 2009
    Location
    'over here' - Ireland
    Posts
    2,532
    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...

  15. #15
    Join Date
    Nov 2004
    Location
    Belden, Mississippi
    Posts
    2,742
    Use the all weather MDF for stability and moisture issues. I have used the Xtera brand with good results. No connection otherwise.
    Bill
    On the other hand, I still have five fingers.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •