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Shim Cutting Jig

As a finish carpenter, I have gone through god-knows how many shims in my career, and I have a feeling I’m going to need a few more in the years ahead.

I have tried a few different variations: the shingle split into 1 1/2-in. pieces, the composite, the solid plastic, the “stack shims” which come in varying thicknesses, and, of course, the pre-cut cedar shims (of which I have probably gone through a pallet-load). All have their place, and I still use a few of the solid plastic shims for exterior projects, but for the past few years I have been cutting my own. This may seem like an exercise in the mundane, but the cost of high-quality shims became prohibitive, and fumbling with poorly-cut cedar shims finally became too much trouble.

First of all, I want to point out that the jig I designed is not an original idea. I’m sure some of you out there already have a similar setup. I simply tweaked the design to be a little bit easier to operate and, in my opinion, a bit safer, too.

(Note: Click any image to enlarge. Hit the “back” button on your browser to return to article.)

Just for basic understanding, this jig is simply a fixed tapering jig. I started with a piece of 3/4 birch plywood that is roughly 10 in. x 10 in.. Why birch? Because that was what I had on hand.
Next, I attached a piece of 3/8-in. x 3/4-in. hardwood to ride in the miter gauge slot of my table saw. Use staples, brads and glue, 1-in. screws, whatever’s handy.
I attached the piece parallel to one side, roughly 6 in. from the edge.
For the handle, I grabbed my shop-made push shoe and traced it on another piece of 3/4 ply.

Really, the style of the handle is up to you: The first shim jig I ever saw just had a chunk of 2 x 4 screwed into it. Just make sure your handle is at a comfortable working height, that it is far enough from the blade for your safety, and that the angle of your grip allows you to press down and forward in the same motion (you can see why I just copied my push shoe).

After you cut out your handle, round over the edges.
I just ran in a few screws to attach mine.

Check your saw before attaching. The distance from your blade to the miter gauge is all you need to know. It’s not imperative that you be exacting or even exactly square with the edge.

All you need is for the base to ride in the miter slot, and for enough of the base to hang past your table saw blade.
Once fixed in place, you simply set the jig into the miter slot and run the base through the blade. Now the edge of the jig is exactly square with the guide.

The shims I like are edge grain, 9 in. long, and taper to 3/8 in. at one end. This is worth noting because the next step sets up your desired length and amount of taper. If you like a shim that is 8 in. and tapers to 1/2 in., or say you prefer 7 in. shims that taper to 1/2 in., the process is still the same regardless of dimension.

I begin by making a mark 1/2 in. from the leading edge of the jig along the same line where I just made the squaring table saw cut. I then make another mark 9 in. from my first. This represents the length of stock I use. Next, I make a line 3/8-in. square to the edge of the jig. If you connect the end of the 3/8-in. line and the first mark that is 1/2 in. from the front of the jig, you will see the exact size of shim this jig will produce. However, I go a bit further.

At the end of the 3/8-in. line, I make another line that is 3/8 in., parallel to the side of the jig and pointed towards the front, then another line that is 3/8 in. and square to edge like the first. This allows you to cut shims that are either tapered to 3/8 in. or 3/4 in. (for those times when you need a SHIM) depending on where you index the stock. At this point, I draw a line with a straight edge from the end of my final 3/8-in. line to my first mark 1/2 in. from the front. I cut out all the lines with a jigsaw. At this point, you are technically ready to cut, but now for the safety part.

My biggest gripe with this jig was that once you passed your stock through the blade, it would occasionally send the freshly cut shim flying because it would catch on exiting the blade. To remedy this, I took a piece of 3/4-in. hardwood that is 1 1/4 in. x 3 in. Off of one corner, I created a haunch that is 7/8 in. x 7/8 in. I installed this piece so that the haunch hangs over the new shim, but not the rest of the shim stock. This acts as a hold down, and will keep your shims from becoming missiles (see drawing below for more detail).

(Click to enlarge) The small hold-down at the rear of the sled is a critical safety feature and prevents the shim from slipping into the saw blade after it's cut. Notch the hold-down so that it applies just a bit of pressure to the top of the stock, and chamfer the leading edge so it's easy to slip the 2x under the hold-down.

As for technique, I take my shim stock (which is usually a 9-in. off-cut of 2 x 6 framing lumber) and nest it against the front of my jig and into either of the notches.
Pass the stock through,

then flip the stock so that the front faces back and the top faces down. Then you repeat this process, “cut, cut, flip… cut, cut, flip…” If you just “cut, cut, cut,” you’ll end up with a chunk that looks like a piece of pie (I know from experience). Of course, you won’t be able to utilize the whole block, but I usually have less than 2 in. of waste for every piece of stock I use.

I have always just cut edge grain shims, but I know there are some carpenters who prefer end grain shims. Supposing you wanted to cut shims from 2 x 6 framing lumber, all you would have to do is change the 9-in. dimension to 5 1/2 in. and use the same notch setup that I described, or use a different layout that suits your fancy.

The only thing I would do differently is change from a ripping blade to a combination. It would probably produce a better and smoother surface.

Finally, a word on safety. We all know that woodworking can be dangerous. Don’t try anything that makes you uncomfortable. Start with a blank, and only cut 6 or 7 shims till you feel comfortable with the process. Also, you can raise the riving knife to where it extends over the top of the blade as an added bit of safety. It won’t interfere with the function of the jig; you’ll just have to take off the anti-kickback mechanism.

. . .

THISisSafety

Please don’t try anything you see in THISisCarpentry, or anywhere else for that matter, unless you’re completely certain that you can do it safely.

. . .

AUTHOR BIO

As a senior in high school, Matt had yet to decide what to do with his life. One of his teachers owned a cabinet shop which had a general labor position open. Having never taken shop, Matt thought he’d try it out. His first tool was a broom, dust pan, and a piece of sandpaper. That was over 16 years ago, and now he can’t imagine doing anything else (the carpentry, not the sweeping).

Matt has participated in many aspects of construction: designing/building custom furniture, installing custom interiors on $10 mil+ luxury yachts, owning a small finish carpentry business, and working as a project manager/lead carpenter; not to mention fixing leaky faucets and rotten siding for little old ladies.

Matt is committed to constantly learning about our ever-changing profession and how to share his knowledge with others. He has been fortunate to have met and worked with many craftsmen in the field who have been generous enough to share their insight with up-and-coming carpenters. Matt feels it’s only fair that he try to do the same, now that he’s in a position to do so.

In the last few years, Matt has begun to focus on sustainable, or “Green,” building practices. He is currently pursuing his Certified Graduate Builder (CGB), Certified Graduate Associate (CGA), Certified Green Professional (CGP), and Master CGP designations from the NAHB. He plans to have them all under his belt by January 2011.

Matt occupies his spare time with two things. One, he has a budding carpenter who, although only 3, has helped Matt out on more than a few jobsites; and two, his helper’s 2-month-old baby brother, who already owns a custom-turned, maple baby rattle. Budding woodworkers? Time will tell.

Matt also finds time to volunteer in his community. He is the co-chairman of the international service committee of his local Rotary club, and is also an honorary member of the foundation board of his local library. He’s also participated in community building projects such as parks and a community boardwalk. Any time beyond that, he enjoys spending with his beautiful wife of nearly 11 years…and falling asleep through most movies they attempt to watch together.

 

Comments/Discussion

38 Responses to “Shim Cutting Jig”

  1. Jesse Wright

    Sweet jig! I cut mine on the miter saw with 1x scrap usually, but I love the jig, Ill have to try that. Great video too! Thanks for the article!

    Reply
  2. Jed Dixon

    Clever jig Matt. Great minds think alike. I use a similar jig to cut wedges for housed stringer stairs, except mine screws down to the plywood sled I made for my Delta 10″contractors saw. Now I’m going to add a holddown to it!

    Gary, I’m glad to see Todd Murdock’s name on the masthead. His sketchup illustrations add clarity to every article.

    Reply
    • Matt Follett

      Hi Jed
      Holy cow I just realized that I hadn’t even replied to your posting.
      I have only met you a few times in person but I have a lot of respect for you & the work you produce. I really appreciate your feedback. I still have to make some time to come to RI & take a hand carved volute class. It’s on my agenda if I can ever break free. Oh, & I’m also with you on Todd Murdock. SketchUp certainly makes illustrating our work much easier. I’m still fairly novice but it is such a powerful tool even at my level of understanding.
      Thanx again.

      Reply
    • Matt Follett

      Ah Jim, to true. The other safety feature I usually use is raising the riving knife over the blade. Put it down for clarity in a few shots & neglected to put it back up. Thanx for the input. We all need to strive to work efficiently, but also as safely as possible.

      Reply
  3. Action Jackson

    I’ve cut my own shims for years as a stair builder and cabinet installer, but here lately I just grab several packs of edge grain pine shims at Lowe’s. I’m usually there about 3 times a week picking up supplies anyway, so I always grab a few on the way out. At $1.50 for a 14 pack that’s just a little over .10 per shim. Most of my jobs are very time sensitive so I try to save time where I can. So, cutting shims, at least for me, is a waste of time and money. But, of course, the best part is just making the jig!

    Reply
    • Gary Katz

      Action,
      You’re absolutely right about the time it takes to cut your own shims. It’s hardly worth the trouble. But for cross-grain shims, which you can’t buy…I’ve cut thousands of them with a jig like Matt’s.
      Gary

      Reply
  4. Rich Atwood

    Matt, I like your approach. I especially like the 3/4″ Wink wink…….. One can never have too many jigs……

    Reply
  5. Joe Stoddard - Mountain Consulting Group

    Sorry to throw cold water on this one –
    There’s a reason Norm starts every show with the “no more important safety tip than these…safety glasses” schpeil. Russ Morash is no fool.

    More importantly -since that video is hosted on a public space (YouTube) that will not have the requisite safety warning in print, all it’s going to take is one DIYer to put out an eye or cut off a finger and you’ll have a personal injury attorney knocking at your door. Even if there’s no fault you’ll have to mount a defense to whatever claim they make, and that alone can ruin you financially and destroy your business.

    I’d embed some strong safety language in the video itself – beginning, and end, both by you the narrator and as text. Ditto for the missing bladeguard.

    On the Jig – IMO would be much safer if you made two gigs – one for ‘shims’ and another for ‘SHIMS’.. vs. having that void when using the thinner setting – where something could slip and potentially kickback and/or shatter. IMO it relies too much on expert-level two-handed control of the piece. And as far as turning the piece 90 to make end-grain shims… I think that would be even more likely to shatter if there was a void behind the piece.

    Again, some DIYer is going to try this, not keep it tight enough in the notch… and end up picking toothpicks of shattered shim out of his cheeks and forehead (and eyes). Someone with no experience doesn’t realize they can get pulled into a running blade in a fraction of a second.

    Finally – having to reach across a running blade with no guard to retrieve your shim is another big no-no. We’ve all done this a million times and most pros will never have a problem – but what about the time someone grazes the blade with their sleeve, or drops the piece on to the running blade? There’s still a hole in the wall of my old shop where a small piece I was ripping got away from me and was hurled completely through the wall. It was over before I realized what had just happened.

    Sorry man – this one really worries me.

    Reply
    • Gary Katz

      Joe,
      GOOD POINTS! Thanks for the advice. I’ve updated that video and included the stuff you suggested!

      Reply
    • Matt Follett

      Thanx for your posting Joe. Your comment concerning YouTube is definitely taken to heart. Honestly, I just posted it there because it was to large a file to send via all my available methods.
      As far as the void between the 3/8″ shim & the 3/4″ notch, I can see your point on the end grain shims where there could be more potential for them to break apart, but after cutting probably 1000s of shims (I usually cut an apple box full in a sitting) I can’t recall ever having kickback. I will say that the wider the blank, the more awkward the feel. I had some left over 2×12 off cuts & thougtht ‘hey, it’s so wide that I will certainly get more shims out of this.’ Which is true, but you also get the feel that you are crossripping, as your blank is wider than it is long. Can this be done…of course it can. Do I do it…no, doesn’t feel comfortable, pure & simple.
      Finally, if you read my reply to comment #8 you can see that I totally agree that safety around tools is no joke. It’s not the million times we do something; it’s the million & first when we don’t pay full attention. Thanx again.

      Reply
    • Bill Tsolias

      Sorry guys this worries me also… I think this is a dangerous jig and makes it a lot easier to hurt ourselves.
      It gives me goosebumps just looking at the last two pictures. All I can think of is as the jig and material is being pushed through with both hands, a slight skew or inward pressure on the material with the left hand, and the blade is pinched and pieces start launching. (Speaking from experience!)
      The holddown also seems skimpy and misplaced. Lauch or “liftoff” is from the backside up not the front of the sled.

      Bill

      Reply
  6. Lavrans

    I’d say it would be pretty easy to address Joe’s concerns about the jig itself by mounting the whole thing in a sled. That’s going to provide zero clearance to the blade and a good drop-area for the shim. The back riser of a sled would also act to stop any runaway shim missiles. Also would make end-grain shims easier/safer.

    Reply
    • Gary Katz

      Lavrans,
      I agree! Even though I still sometimes use my little shim jig for cross-grain shims, you’re right! I should be using a sled–though carrying that to a jobsite….

      Reply
    • Matt Follett

      Interesting thought on the sled. Never really thought about it as I’ve never had much trouble with this one (save the occasional knot in my material). I’m sure there would be some way to tweak the design to make it zero clearance. Perhaps you should do the next evolution & see where it comes out then. My only advice…don’t forget your safety glasses ;)

      Reply
    • Joe Stoddard

      Lavrans – that’s exactly what’s needed here – a sled. Good thinking !

      JLS

      Reply
  7. Patrick Grieco

    Since we’re talking about safety I would add that wearing gloves around any power tool is a BAD idea. Wearing gloves could turn a severed fingertip into a far more severe injury as the blade grabs the fabric and pulls it around. Don’t believe me, take a circular saw and lay it down on a rag, drop sheet etc. as the blade is coasting to a stop. It’ll take you an hour to cut the fabric off the blade that’s been wrapped around it about 50 times before the blade finally stopped. Now imagine if your hand was in that piece of fabric. Not a pretty site. This happened to me once, thankfully it was only a drop sheet that got hurt. I also know a cabinet maker who had his hand pulled into a cabinet saw because he was wearing gloves. Luckily he only lost one finger but I can guarantee he has never worn gloves around machinery ever again. This goes for bandsaws, drill presses, and every other tool you can think of. I know our chosen profession is inherently dangerous but we shouldn’t make it any easier to hurt ourselves.

    Reply
    • Matt Follett

      Really like the last line of your comment Patrick. That sums up nearly every concern about safety in our profession. Have never had a close call with gloves in the years since I’ve started wearing them, but I hear ya on the ‘thread’ example. Had a belt sander grab the front corner of an untucked flannel shirt & before I knew it, the sander had bogged down right under my chin. Needless to say, ever since that day I like a my shirts with short sleeves & tucked in. Good comment.

      Reply
    • Matt Follett

      Oh, & if you must wear long sleeves…UnderArmour COLDGear. Course it gets chilly around here. That’s the best option I’ve found.

      Reply
  8. Jim Bunch

    Made this jig yesterday, works GREAT,have enough shims for the next year,plus some kindling for the fireplace..

    Reply
    • Matt Follett

      Very nice. Thanx for posting Jim. Did you cut your shims with the grain or cross grain just out of curiousity?

      Reply
      • Jim Bunch

        Did with the grain,since I have Fien tool for trimming shims and such…………

        Reply
        • Matt Follett

          I do likewise minus the fein. I have a fein but I just use a pullsaw. Although my biggest issue with hand cut shims is that I usually cut them from KD fir & they certainly don’t cut nearly as easy as cedar or pine shims. The Fein (or any of the current knock offs) is a good idea.

          Reply
  9. Don Kerkhan

    Somehow, I like to use the old 18″ cedar shingles that I usually remove from an older home for shims. Sometimes I’ll stop by a site where they’re being removed from the exterior and discarded….and they’re usually free for the taking. As long as they’re as whole as can be, I take the shingle, place it on the bench, and slide my knife over the face of the shingle about 1-1/2″ from the long edge, once or twice. Pick the shingle up and just bend it @ the score mark. Repeat as many times as you need shims. Always cut more than you think you need. They usually disappear quickly. Now you’ve got shims of quality material that can shim most anything. Another good thing is that they’re 18″ long. If I ever cut the thin end off, and it’s long enough to use somewhere, I always save these little jewels ’cause they do come in handy for those tight shimming jobs. I don’t tell you how I do the actual cutting of the shims ’cause you might hurt yourself. I’ve been doing it for some 39 years, and I haven’t had a problem with this system yet. Happy shimming to ya.

    Reply
    • Matt Follett

      Hi Don. Anything that suits your needs is the way to go, especially if you don’t have to travel to tablesaw to cut them. I’m assuming that these shingles are a bit better quality than what we use today. I’ve tried spliting left over shingles as I usually work in new construction, but they are always so rough & random.
      39 years & no issues? I’m shootin’ for the same number & so far so good. Thanx for reading.

      Reply
  10. CodyNCanada

    When I was taking my 2nd year schooling, the class was doing some shop work and the instructor had a couple of us cutting 2×6’s down to 10in. We had to do about 50 of them but had no clue what they were for, so I cut my 5 that I needed then proceeded to the table saw. The instructor called all the students over to show them the proper way to cut shims on the table saw(Matt’s Jig). He gave the class the lesson, and said DO NOT PULL THE STOCK BACK through the blade. I cut my shims, then I remember looking over at the chop saw and one of the students was trying to buck through 5 2×6’s staked on top of each other and told my buddy that guy is going to chop a finger off….. this guy proceeded to the table saw, and cut a couple of shims and said this is too slow and pulled the stock back with the jig, and the blade bit the 2×6 and pulled his hand right across the blade, he was lucky enough that he only grazed his hand and all of his digits were intact but what a mess.

    So just be careful when you use this jig, like any other operation on the table saw.

    Reply
    • Matt Follett

      Cody
      Thanx for posting your story & especially your last line.
      I agree there will always be those (hopefully a small minority) who try to speed things up by bucking safety or arbitrarily working without proper focus. Either can quickly be a nasty statistic. I’m sure everyone who has posted on this feed has experience ‘kickback’ or some other tablesaw mis hap during their career. We all need to be cognizant that what we do can be dangerous, but with proper respect for the tools we weild, using techniques that maximize safe practice & being attentive to the task at hand, we can be safe, productive & even possibly enjoy the work we are doing.
      Thanx again for reading.

      Reply
  11. Rob Potter

    Thanks for the article and great video.
    I quickly put together this jig the morning after seeing the article to cut some wedges for the project I’m doing. I worked great. Thanks for the inspiration.
    I appreciate all the comments here on safety. It’s a good discussion to be having, and always like when TIC authors respond to the comments posted.

    Reply
    • Matt Follett

      I whole-heartedly agree Rob. That’s why I like this forum. The constructive give & take makes us all better in the end.
      Glad the jig worked out for you & thanx for posting your results :)

      Reply
  12. Bill Amaya

    We made shims on a table saw with a jig that is existentially identical to the one in the article. the last time we did this the shim got lose in the jig and exploded bringing the throat plate with it. I thought we were going to end up in the emergency room. We now cut shims on the band saw. So much safer there is just no comparison. Please, please do not use a table saw to cut shims!! Anytime you make a cut and end up with a piece of wood trapped that is not completely under control you are just asking to be hurt. IMHO Specifically if the leading end of the shim can drift away from the jig and/or lift up it is not safe.

    Best regards,
    Bill Amaya

    Reply
    • Matt Follett

      YIKES! Throat plate & all? Not cool. I’m trying to wrap my mind around how that could happen if your jig was over a portion of the throat plate. Either way, hope everyone was alright.
      I do like your idea of cutting on the bandsaw. I would do likewise…if I had a bandsaw, but it’s sounds like a great alternative.
      Thanx for taking the time to post.

      Reply
  13. Ray Menard

    I would NEVER do this! Too many variables – too much 2 hand dancing over & around the saw blade. Yikes, yikes & more yikes. The gloves & the no safety glasses issues made me very uncomfortable too. I know you knew better, but it is just that moment of inattention to putting your glasses back on that reinforce my other concerns. Not trying to be a smart alek here, or disputing your years of success & professionalism, just saying that even with my 30+ years working a table saw I would not be sanguine with this technique – just my 2¢. The sled concept has merit.

    Reply
    • Matt Follett

      Hi Ray
      I too would like to see the sled concept reach fruition. Is anybody out there using a sled to cut shims? I feel you on the glasses. The gloves are worth noting but I have to say I’ve never had an issue. Of course we all know it just takes one ‘issue’ to make a lasting impression. It just seems to me that if you are being cautious of the blade, gloves should be a none issue unless they had some sort of loose cut or they were terribly frayed. The ones I had in the video have been used for a couple of months but they get replaced quite often (I buy in bulk) as they just get torn up. I figure my hands could look like that or the gloves.
      I do appreciate your posting. You chime in with your 2 cents anytime.

      Reply
  14. David Tuttle

    This week I tore out some bad work and when I was looking at how I had to put stuff back in I remembered your “SHIMS” So I’ve made the jig, now I have myself SHIMS and Shims for the next couple of weeks, and they are sweet shims… Sometimes the humble shim is over looked, thanks for the article.

    Reply
    • Matt Follett

      Haha, thanx David. I keep toying with the idea of writing a ‘shim sled’ article because of the lashing that I took on the safety of this one. Still, good to know it’s working for someone other than me.
      Thanx for posting.

      Reply
  15. Dan van Nes

    I like to cut my own shims because I always have a ton of scrap and I find its a good way to use it up. But I was once told that spruce shims (or shims cut from framing material) will cause shifting due to the expansion of the shims more than cedar shims. Is this true? Am I better off cutting cedar shims ( which would be less cost effective)?

    Thanks for your input

    Reply
  16. Rene

    Hi, Can you use something like this to cut 4 inch wide wooden shingles?

    Reply

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