184 – Coves on the Tablesaw & the Parallelogram Cove Jig

Video - October 11, 2012

Many people are surprised when they find out they can make incredibly beautiful (and large) coves moldings on the tablesaw. I know I was! In this episode, I’ll give you a rundown on the process for creating both symmetrical and asymmetrical coves. I’ll show you several ways to set up for this operation, but my favorite involves the use of a parallelogram jig that was inspired by a Fine Woodworking Article by Stuart Sabol (subscription required). His jig is primarily for setup only, so I figured why not make a jig that would also double as a fence system.

Once you have your coves cut, you’ll need to clean them up. Unfortunately the blade leaves a fairly rough surface. So I’ll show you a few good ways to smooth the surface to perfection.

And I didn’t mention it in the video, but the best blade for this type of operation would be one with a square tooth grind. That should leave you with the cleanest surface. My 40 tooth Forrest Woodworker II did a pretty decent job without any square teeth. And here is the link for the program cove calculation program over at FineWoodworking.com: Cove Angle Calculator

The Parallelogram Cove Jig

I made my jig from 3/4″ Baltic Birch plywood and several parts from a Rockler Jig IT Hardware Kit. Here are the dimensions of the jig parts:

2 main rails – 54″L x 4″W
2 cross-rails – 13″L x 1.5″W
8 rail supports – 4″L x 2″W

Remember that none of these dimensions are in stone. You might might to make your jig longer, wider, taller, etc.

Products Used

Rockler Jig IT Hardware Kit

Resources

Cove Angle Calculator

Discussion

Brandon October 11, 2012 10:56 am

After clamping the rails down couldn’t you just take the bridge pieces off the ends? Then it wouldn’t matter how tall the piece is.

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- Ronn October 11, 2012 11:31 am
  
  I noticed in the last scene of the video demonstrating the spacer blocks to allow thick stock to pass under the cross arm that the spacer block was skewed at and angle. This lets the corner of the spacer project into the path of of the work piece. I suggest that the spacer be significantly smaller so that if it does rotate or if it is not aligned perfectly when tightened, that no part of it will project into the path of the workpiece.
  
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- thewoodwhisperer October 11, 2012 12:50 pm
  
  Sure!
  
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- Michael R. Alvers October 16, 2017 3:29 am
  
  Ingenious :)
  
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Andrzej October 11, 2012 11:51 am

Maybe an idea for a jig to operate thick pieces without limits.
Try doing the jig long enough to go outside the table and… flip it over to have connecting bars below the long rails.
Just an idea :)

Best regards
— Andrzej

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- Andrzej October 11, 2012 1:07 pm
  
  A sketchup draft of my idea:
  https://dl.dropbox.com/u/6075617/jig.jpg
  
  Regards
  — Andrzej
  
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Ronny October 11, 2012 12:38 pm

Great show I have seen this done several times But nobody realy shows all the steps Thanks for taking the time to show this step by step

And thanks for the Spagnuolo Fix

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TerryMcK October 11, 2012 1:15 pm

Clicking that Blip button starts the audio somewhere else. I couldn’t find where it was playing. I had three audio feeds going at once, one from the actual video and two others from the ether. I’m using Windows 7 and Chrome. Very spooky!

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- TerryMcK October 11, 2012 1:42 pm
  
  Great video by the way
  
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Alan October 11, 2012 1:48 pm

great video marc
something funny happening in the vieo for me aswell. your voice was a bit out with your mouth moving. kinda looked like when you see someone foreign talking but it is dubed in over them ,lots of mouth movements but no sound.

i really must try this sometime. i have no use for the resultant piece but i want to play anyway.

i would agree with putting the bridge piece underneeth.

how do you feel this teckneque works when doing a whole projects worth of components.

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- thewoodwhisperer October 11, 2012 4:16 pm
  
  It is certainly a time-consuming technique, but it does work. And even a full project’s worth really wouldn’t amount to that much material. I imagine it would be used for trim or molding so there shouldn’t be too many linear feet.
  
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  - BarryO October 21, 2012 2:27 pm
    
    FYI, CMT makes a special cutterhead just for this operation: http://www.amazon.com/CMT-235-.....s=cmt+cove
    
    I bit pricey (although the price seems to have come down alot from what it used to be), but maybe it’s worth it if you do alot of these cuts. I’ve nver talked to anyone who has ever used one. It would be nice to see someone review it sometime (hint, hint. ;)).
    
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pagel October 11, 2012 7:59 pm

I was paging through the Rockler professional catalog just now and on page 37 I see that Rockler is selling a souped-up version of your cove cutting jig. They call it, “An ingenious clamping system…” :)

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Patrick Schupbach October 12, 2012 5:41 am

Once again, well done. Very imformative video!!! The possibilities are endless!!!

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Keith October 12, 2012 6:27 am

Mark,

I think you got it right the first time, the cove offset was 1/2″ and you marked it that way on the piece. The cove height was 3/4″. The added text in the video corrected your audio saying the offset was 3/4″. I think you got it right in your audio. Or did I miss something?

Thanks for the information. Where have you used this technique on a project?

Keith

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Philip Shie October 12, 2012 10:18 am

Love your shirt…

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Joel October 12, 2012 2:34 pm

doing this to make my own crown molding for a built-in

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Scott October 12, 2012 6:41 pm

Another way to sand out the cove is to build a little box out of lightweight cardboard which covers the whole width of the work piece, and has the bottom edges cut to match the contour of the cove. Then place a “more-than-big-enough” piece of cling wrap over top of the work piece, set the cardboard box on top of that, and fill the box with some prepared auto body filler.
Once the body filler has set, you will have a perfectly form-fitting sanding block that covers the while width of the cove. If you have a number of large pieces to sand, this will speed the process greatly.
Great video Mark, can’t tell you how much I appreciate all your efforts with the Woodwhisperer… Rock On!!

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Michael E. October 12, 2012 8:15 pm

Great video, but I’ve got to ask, what was that little yellow sanding block you used that you could adjust to the shape of your contour?

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- thewoodwhisperer October 13, 2012 7:15 am
  
  It was a free gift at a woodworking show. I’ll have to track down the manufacturer for you. IF I can find it. :)
  
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Kevin October 12, 2012 8:37 pm

Someone mentioned Rocklers jig…I bought it on sale a while back but have yet to use it. I like yours better and looks like it would handle thicker stock better, and I dont think rocklers is guaranteed to be parallel…however, rocklers does have miter slot bars so it securely stays put. Nice work and thx for this.

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Ben October 13, 2012 8:12 am

I just found your site and I just have to say you guys are amazing. This video was really cool, I would have never imagined you could do something like this with your table saw. I’m really looking forward to going through the rest of your videos and and seeing future videos but for now I just wanted to say thanks!

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jared October 14, 2012 8:02 am

michael e. i believe the yellow sander said ex factory on the side of it

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Paul October 14, 2012 9:29 am

Marc, have you tried using a festool LS130? Would it work well in this situation?

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jlaviolette October 16, 2012 5:39 am

What would be the best blade choice for something like this? Am I unnecessarily concerned about deflection with a thin kerf blade?

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- thewoodwhisperer October 16, 2012 7:01 am
  
  A square tooth blade is best. And I don’t use thin kerf myself but I imagine if you take it slowly with light cuts, you’ll be fine.
  
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Matt October 16, 2012 7:04 am

Marc, just wanted to thank you for the informative videos you have produced. I am a hobby woodworker, and wish my day job would quit gettng in the way of the funner (is that a word?) things in life! I’ll keep watching and learning, you keep up the great site! Thanks for helping us weekend warriors!

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Larry October 16, 2012 7:02 pm

Thanks Marc! This is awesome. I don’t have a project at the moment requiring a cove but I can’t wait to incorporate this into a project. Thanks again.

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Tom Collins October 19, 2012 5:17 am

Great video! Thank you. Is this process hard on the blade? Does it dull it faster? Do you use you normal saw blade, or do you use a special blade for cutting coves?

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- thewoodwhisperer October 19, 2012 6:29 am
  
  I don’t think it dulls the blade any faster since you’re just cutting wood like you always do. You’re just cutting a lot of it. I use a regular ATB blade for this but as mentioned in the article above, a square grind blade would be ideal.
  
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Jerry MD October 20, 2012 3:39 pm

Hey Marc what gives with your videos I can’t watch anything. A while back I got this red screen saying I needed a Blip player. I checked out Blip.com and E-mailed them asking them why I couldn’t watch your program. They E-mailed the following : “As that message explains we do not allow playback outside of the Blip player and are taking more aggressive actions toward limiting this behavior as it causes excessive bandwidth usage and many times is used by accounts to circumvent our add network in favor of their own.” Then they said I could find directions how to embed a code to watch a single episode player at their web site. Whaaaat. Their telling me that I can’t watch any episode on you own web site but have to go to theirs. Whoaaa! Today I see your format has changed but still can’t watch anything. Got an answer?
Sincerely, A sad woodworker.

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- thewoodwhisperer October 20, 2012 6:33 pm
  
  Hey Jerry. I know Blip made these restrictive changes recently and it’s a real shame. To my knowledge, this only affects direct downloads. Some people can still download though and it depends on what browser you’re running and with what operating system. Either way, the policy sucks, but we’re stuck with it. That said, there should be absolutely no restrictions on watching the embedded version here in our site. I haven’t heard any other complaints other than one guy on Lumberjocks that couldn’t the embedded version to play. The video has been downloaded and viewed nearly 20,000 times already so this is definitely not a widespread issue, which would make it very tricky to diagnose. So I would suggest two things. First, makes your browser is updated fully and make sure your Flash is updated. Second thing to try is a different browser.
  
  The final solution is to perhaps use something like iTunes to download the videos. Blip has not yet blocked that particular method of downloading.
  
  Sorry for the inconvenience, but this is what we get for using a free service. Well technically it isn’t free as I do pay for the “pro” service, but apparently that doesn’t buy me much love in this regard.
  
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Dave K November 3, 2012 6:47 pm

Great video Marc!. I used this technique to make some crown molding to match the rest of the room for trimming out some built-in cabinet / bookcases.

I have another suggestion for a sanding block. I’ve had good success with using 2″ thick extruded foam insulation board to make custom concave or convex sanding blocks. You can use a rasp to cut the profile, then just use adhesive backed sandpaper or regular paper with spray adhesive.

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John December 6, 2012 6:15 pm

Interesting way to use a table saw, you are right this goes against everything I have ever learned about how to use it. I like jigs.

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Bob Crosley December 10, 2012 11:03 am

Excellent video Marc. I never would have guessed that assymetrical coves were anything other than the product of trial and error and more than a bit of guessing.

I do have a question. Fairly new to the hobby and want to make sure I get the terms right. You used two aids in this video for setup and sanding. You referred to the sanding tool as a dealie, but the angle finder was a dealie-whacker.

What is the proper usage of those terms and what is the real difference? I’d hate to embarrass myself in front of experienced woodworkers by using the wrong one.

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- thewoodwhisperer December 10, 2012 11:14 am
  
  Was the sanding tool the one that conforms to the shape? I am not sure there’s a good name for that. It’s a “sanding tool that conforms to various profiles”, lol. Maybe a “profile sanding block” might be a good description. The angle finder was a bevel gauge.
  
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  - Bob Crosley December 10, 2012 12:01 pm
    
    Sorry Marc. I was trying to be clever by asking for a differentiation between dealie and dealie-whacker. I failed. :) Have a great holiday.
    
    Reply
    - thewoodwhisperer December 10, 2012 12:43 pm
      
      lol well it is my fault for using such complex terminology in the first place. You see, a dealie is like a more basic version of a dealie whacker. So you can expect to pay significantly more for the additional whacker functionality. That pretty much sums up the difference. :)
Brad December 12, 2012 1:16 pm

Well done Marc. I’ve used my router table for smaller versions of that cove but was looking for a good way of making larger cuts. I’d heard of this technique, but wasn’t sure how to get started to get it right. Learned a lot as usual. Thanks again.

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Edward December 25, 2012 2:05 am

Can we call it a lucky coincidence?
1. My neighbour broke her beloved glass table bowl 4 days ago…
2. a present I ordered for her early december didn’t arrive in time…
3. browsing around I found this technique…
4. I happened to have some nice Maple leftovers from some window sills….
5. all this together turned out into a new table bowl…
6. so I had a fairly nice shaped, personal and creative X-mas present for her after all …and she liked it :)))

I’ll post some making-of-pictures on my blog!

Merry Christmas and a happy 2013 to you all.

Edward

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Brandon December 26, 2012 5:17 pm

Are there any safety concerns with the size of your table saw when using the method? I have an older craftsman portable table saw. Its a bit on the narrow side from front to back. I suppose support rollers or in-feed/out-feed tables would be sufficient to offeset the weight of the longer boards.

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Donovan December 30, 2012 1:00 am

This is perfect, i’ve been thinking about buliding a fram for some art my wife bought at an auction. I think I’m going to incorporate a cove in the final product.

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Jesse June 11, 2013 7:45 pm

Great video as always. How would you recommend doing this on a 10′ piece of wood? Say, if you were going to do some cove for crown molding? Thanks, Marc.

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- Marc Spagnuolo June 11, 2013 7:47 pm
  
  Hey Jessee. I’d probably use the same techniques and set up some feed rollers at both ends to support the work. Should still work.
  
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Mick July 13, 2013 12:21 pm

If you used round support/spacer blocks you don’t have to glue them to the main rails and they would be stackable if you need more clearance on the cross rails for thicker pieces of wood. They also wouldn’t interfere with any angle that the jig is set to. You could also drill holes in the main rails at different lengths making the jig length adjustable, that way it might make clamping the ends of the jig to the saw table easier.

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dale rex September 22, 2013 4:57 am

Great video Marc. I do alot of repairs on old homes for a living and needed to make some large cove molding to replace areas that had rotted from roof leaks. I had to match the existing trim on the house. I never used the table saw method before and was a little scared to try it.these moldings were too large for a router bit to make. After watching the video I was going to experiment a bit a make some test pieces. I traced the profile I needed on the end of a piece of cedar (just in case I was successful with my test pieces I could use them for the actual replacement moldings). I sighted in the blade height and angle of feed from the table top, set up 2 fences with scrap 2 x 4 material. Ran it through with multiple shallow passes and in one shot I had my perfectly matching coves moldings! I could believe how easy it was!Took 15 minutes.! Thanks Marc for the great video. P.S. I am probably going to make the jig soon for future use.

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Marc Choronzey November 28, 2013 6:48 pm

Nice video. As always, great fun to watch. I learned to set-up with a (much) smaller parallelogram and then we would use two 8′ long 8/4 jointed oak boards. (Or just one if I was cutting a cove on the side of a raised panel (as an alternative to using a router table). Of course, it requires to make sure the oak boards weren’t warped but that system worked very well. I also like your “mach 2” cove jig very much! =)

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Pat January 19, 2014 8:50 pm

Marc, I would like to use this technique to make small coves for drawer pulls, and having trouble in my head trying to figure out how to make 4 coves on one piece of stock offset to the left and right and then rip the stock to the correct width?? I will definitely building your jig. Thanks for any thoughts, Pat.

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- Marc Spagnuolo January 21, 2014 10:35 am
  
  For something of that size, have you considered just using a router bit instead?
  
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Phillip Andrews February 3, 2014 4:15 pm

Mark, really enjoyed the video. I have made the jig and the molding. It worked out great. I plan to use this as crown molding on top of a large bookcase. Is there a specific angle that the bottom should be cut to make it work with the angles for store bought crown? I have never worked with crown before. Thanks in advance for your help.
Phillip Andrews

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Tom June 4, 2014 9:01 am

I’m in the process of making a bar including bar rail. After watching the video of Cove cut on table saw I tried in out on scrap and feel confident but How can I find the angles of the rabbett cuts on the underside of bar rail?

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- Marc Spagnuolo June 4, 2014 8:23 pm
  
  I’m not cure I can answer that without some sort of image of what you’re trying to produce.
  
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  - Tom June 5, 2014 9:23 am
    
    I have images available. Do you have an email address to send them to?
    
    Reply
    - Marc Spagnuolo June 5, 2014 11:53 am
      
      you can use our contact page: http://www.thewoodwhisperer.com/contact/
Billy D August 15, 2014 1:41 am

looks like a great idea, with many other applications, was wondering tho, does a regular saw blade flex too much while cutting, would maybe a stackable dado blade work better?
thanks bunches, I have gotten alot if inspiration from your work

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- Marc Spagnuolo August 15, 2014 6:17 am
  
  Hi Billy! As long as you don’t take too big of a bite, there isn’t much in the way of flex or deformation of the blade. Obviously a dado stack would be stiffer but I’m not sure it really buys any sort of advantage.
  
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Scondor November 16, 2014 9:09 am

Great video, just got my jig knobs from Rockler and I’m building my jig now. What I’d like to know is whether grain direction is a factor when cutting with this jig, like grain direction is important when using a router?

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Robert Henry August 2, 2015 11:53 pm

You can make an inexpensive and significantly more aggressive single pass cutter by simply stacking multiple ripping blades with the teeth staggered to nest. Move to a single blade for the final pass.

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Ronnie Struble April 10, 2016 8:54 am

Great video. I’m building my jig now. I’m using your cove molding to build legs for and old chest and it looks like it will work very well. I have to cut a cove in them on flat stock. Where can I get the calculator you used on show for angle of cove? Maybe I missed it on video. Thanks again great job!!!!!!!!!!!!
Ron

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wilson robey April 17, 2016 10:31 am

Is there any way you could incorporate the tee slots on the table saw to do the clamping for the jig ?

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Wellington Rabelo November 2, 2016 4:11 pm

Parabens pelo video explicativo e profissional como voce que colhe os frutos de sua profissão por ajudar a todas as pessoas … PARABENS

Wellington Rabelo – São Paulo – Brasil

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Surren Wijeratne January 8, 2018 9:14 pm

Great , making the coves on a table saw and cove , a very good lesson , Thanks Marc.
All the best to you.
Wish you happiness & Good health.
Surren
Sri Lanka

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Cliff Leonard February 2, 2018 5:42 pm

Couldn’t find the little yellow EX-Factory adjustable sanding block but I did find a little green one.

https://www.scosarg.com/variop.....ding-block

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Charles Frean April 6, 2019 7:05 am

Thank you for this and your other excellent videos! Please could you provide a new link to the Cove Angle Calculator? The link in the text doesn’t seem to be working.

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Jeff Hinke November 15, 2020 6:59 am

Hi Mark,
I didn’t see anyone comment above so forgive me if i missed it. The apex of the asymmetrical cove is cut to the opposite side to what your drawing (plan) was. See 16:09 and 16:30 marks in the video. In your case, it doesn’t really matter as the wood doesn’t have any specific grain characteristics that you are trying to highlight or capture, if you will, so you can just turn your piece. My sole use of this technique has been in making the Jewelry box from issue 46 of WoodSmith magazine, and until this particular rendition (#7) I have always been able to use the settings given in the magazine article. This time, using a piece of bocote, I am trying to center some particular grain in the center of the asymmetrical cove to waterfall around the box. After ripping the stock to width, it took on a pretty severe end-to end warp which I eventually had to mill back to flat. So now, faced with thinner-than-planned stock, I needed a new cove depth, so I have computed the new parameters necessary using the Sabol calculator. But I couldn’t figure out in my left-handed brain which direction the apex would be from center. Your video has distinctly pointed that out to me and I am now confident that I can get that grain located in the cove exactly where I want it to. I specifically want to complement you on leaving these shots in the video as is, as some might consider these a goof-up. But actually it points out a detail of the asymmetrical cove that I was specifically looking for when watching the video. The apex is set towards the rear of the saw (or back of the blade). So Thank You! I actually use the Rockler Jig (I had a coupon :) ) only because of it’s method of clamping using the TS slots. My outfeed table doesn’t move out of the way and to use clamps would require a super long jig.

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184 – Coves on the Tablesaw & the Parallelogram Cove Jig

The Parallelogram Cove Jig

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