184 - Coves on the Tablesaw & the Parallelogram Cove Jig
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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 www.finewoodwor...
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Possibly the best woodworking video on TH-cam! Thanks!
Always wanted to try the coving process and now at, 76, I finally have a project that requires it. Thanks for the straight forward and easy tutorial. Takes all the mystery and most of the danger out of it.
At first I didn't think the a-symmetrical was going to look good being a symmetrical guy. I always have to figure things out on the job and this video really helped show me a whole dimension with the table saw I haven't discovered yet. One of those outside the box ideas for sure. Most people just think in terms of straight lines with table saw. Thanks for the great video Marc.
I was just wondering. I inherited a workshop with a lot of tools and i am trying to learn how to use them. You and Steve Ramsey have been a ton of help! Thanks and keep up these great videos!
Thank you - you always explain processes so well. I used this with good success.
Yes indeed. Feel like we can really get on with our lives now. Quite a relief!
One thing you might consider doing is dovetailing the joints first. You can even do this technique on the fully assembled box. That way you won't have to worry about joinery after the coves are cut. It'll take some practice runs and planning but it can certainly be done.
I am making a jewelry box for a fundraiser and am doing mitered corners with sliding dovetail splines. If it was all assembled do you think I would blow out the miters? Fully assembled sounds safer and more convenient
Fantastic demonstration. I love the jig you made for this process. Love your channel and will continue to watch. Thanks again,
Al from Maryland
Quite a good coverage of the topic, thanks.
great video, I'm trying to make some fancy handrails and this is the answer I've been looking for, thanks
Thanks for the awesome video! I really want to try this. But as you said, the limit is my creativity. :)
One idea for cutting 8/4 with that jig (without the bridge interfering) would be to get your angles and width and all of that set, clamp the main rails to the table saw, and then just unscrew the knobs and remove the bridge altogether.
Thanks for the awesome vids!
great vid. been doing raised panels on the table saw for years. gonna have to make up one of these jigs for moulding tho. i like the looks and function of it and alot safer than one fence.
Congrats on selling the old house! I know that must be a big weight lifted off your back. Thanks for the video Sir!
Never thought to use a table saw as a shaper. Thanks for the tip!
Thanks for sharing your insight and details on this process. I screwed two planks into my table saw sled, clamped the sled down and began my passes. Perfect semi-circles for my project! (I used this "step" for my dividers and completed my version of Steve Ramsey updated utensil tray) Again, thank you!
Heres a possible sanding solution:
Place a piece of scrap at the end of the work piece so you can draw the exact curvature of the work piece. Cut multiple pieces out on the band saw at the same time so they all have the same curvature. Sand these down to get them as close as possible to the exact curve of the work piece but it doesnt have to be perfect, just close.
Now attach these pieces together so as to create a form for your sandpaper. Attach a piece of foam to the sanding side of the block (any kind of soft flexible foam will do) you just made using spray adhesive ( or something like that ). Wrap on the appropriate type of sandpaper for the job and go at it. The foam will offset any flaws in your sanding block giving you that flexibility from not being perfect on the band saw.
There are many ways to adapt this method or change it to your liking, but you get the idea.
really amazing technique. and very well explained too. thanks so much
I did this on a faux log bed I built for my wife. The footboard was two 6" horizontal logs sawn in half attached to a vertical 12" log for the leg. I had to cove the end grain of the smaller logs to mate with the posts. I started by mitering to remove most of the material. Then I build a sled to support the 50" or so long board in the air and to keep the mitered end grain flat against the table saw top. One hand in the air holding the log, other hand operating the sled. Got to be a better way.
Another great video Marc. Thank you very much!
Here’s a thought , if the knobs were reversed so the jig could be turned over, the jig “could” potentially be more secure while cutting the cove.
Great video!!!
yeay! free video! thanks mark!
Marc,
I'm kinda new to woodworking & like your videos. w/o any help, I made a cove jig that has some properties like yours. I failed to make it into a parallelogram (mine is simply two different fences) & I see that as an easy change. W/ that being said, I found it difficult to clamp it at times & made slots in each that have Tbolts that run in the slots on my table saw. It did allow me to minimize the clamping. Food for thought.
Thanks for the ideas.
Rob
Hey Marc that jig looks like it would work as the exact dado jig.
I like the parallelogram. I cut coves before using only one straight piece clamped to the table, but only incrementing a tiny bit each pass. Your way is safer. Thank you
There's no way you're old enough to recall the Laugh-In reference on your T-shirt!
I made a night stand out of cherry back in junior high and the shop teacher did this to the feet. It went to a pawnshop to pay some bills years ago so now I want to build a set I can keep now that I am older and that money grubbing, I digress. I have wanted to learn how to do this and now I have an idea how to do it safely.
Wife: Honey, why are all my clothes on the floor in the closet. Me: Feel how smooth this cove is!
Brilliant, just what I was looking for - perfect.
Great tips. This must be cheaper than buying molding.
Excelent video- very clearly explained
Hi Wood Whisperer, Thank you for sharing your wonderful idea regarding crown molding. I'm from the Philippines and currently working in Saudi Arabia. I'm going home for good this coming December and continue the finishes of my house. My question is how are you going to get the angle of crown molding that is attach on the ceiling and on the wall.
great videos. i do think its worth mentioning that if you do use a single fence that it goes behind the blade (closer to operator), so if anything the blade is pushing the material into the fence. a few years back i was set up in reverse and cut my middle finger off as the peice left the saw and my hand came down in place of it.
I guess I'm a bit late to the game, but I have exactly the same observation. If using a single fence, it should be set such that the blade tends to push the work piece into the fence. If in doubt where that should be, use 2 fences like Mark does - definitely the safer way.
Excellent video.
A flat ground blade is best. Most ripping blades will suffice. And you can certainly use purpleheart wherever you want in the piece. Depends on the design and the look you're going for.
I think turning the saw off is the "proper" way to do it, in terms of absolute safety. But to be honest, I frequently make small adjustments while the blade is moving. Probably shouldn't do it as much as I do.
I will make one off those jigs but one thing i think i will do is on the loong pieces ( front and back fence) i will make a 1/4" groove in the middle to take T nuts /bolt to be able just attach the jig to table t slots and not needing to use clamps , if that will work
Thanks Mark.
Top marks!
The wood whisperer, more like Peter puffer lol
One of the few times I'v tried this , I used a noodle (pool toy) which was good for symetrical shapes.
I was going to make the same comment, pool noodles are the best for contour sanding.
cool idea, well done
I need to make a 1/2" deep grove across a 3' 2x4. It is to allow a 4" vent pipe pass under it in a limited space. Any thoughts?
When I build mine I think I'll fit dowels in the extra height spacers and keep them on the fence rail until I need them.
An old timer told me he uses glass for curved things like the seat of a chair. Would that work to smooth this out?
This is an old video from before the wall went in. And I can't give you a shop tour because someone else owns that house now. :)
Would it be possible to safely make rosette block molding using a variation of this process?
My question is this: when you find the length and the apex and then you try to offset the cove by say 1/2 inch. Can you just measure from the center to the top of the cove offset to get the angle required to set the tilt of the blade?
Хорошая Столярка!
Same jig can be used on a router to make grooves. I should build one for my 10 sq ft shop.
If I want a tighter radius can I use a 6" dado blade with a 1/4 "setting?
What is the best table saw blade for a cove cut? I presume it is a crosscut blade, but is there a specific type that is best?
Great video. Thanks!!!!!!!
For higher pieces, why not clamp down both rails and simply remove the bridge pieces?
Wouldn't it be easier to turn the parallelogram jig upside down and removing the support blocks? That way there would be no restriction on the height of the material you are using, and you could put one of the connecting rails right up against the top of the table saw, which i think would make setting up the jig a little quicker? Those are just my idea's and I would greatly appreciate your opinion on if you think they would improve on the design our not.
Hi I just that thought this was a great informative video I have made coves before bit my method was a bit more hit and miss. I'm not sure how stupid this suggestion sounds but if you are only working with smaller material would it be practical to use a long sanding drum with soft outer fitted into a chuck on the headstock of your lathe secure the other end with the tail stock and sand the cove out at low speed on the lathe.
Thanks for another great video, Marc. I have some 6" cove crown molding to make, and I'm wondering if it would be easier to remove the bulk of the cove with a dado blade in a conventional fashion, first. You know - deepest at the apex of the cove, drop down a little and make a pass flanking the middle channel on the left and right, and repeat, working my way out. Then use the parallelogram jig to cut the coves like you show above. Make sense, or am I thinking too much about it? Thanks again.
I think I"m just gonna buy the Rockler cove jig. I might need a whole house worth of cove, but I don't have a whole shop at my disposal.
Maybe you could just make it longer then turn the parallel jig over so the knobs are underneath ?
that is an amazing miter gauge
What is the name of the adjustable sander (that takes the shape of the groove) in your video?
Instead of placing spacers in the jig for thicker stock, why not flip the jig upside down? Wouldn't that work just as well?
thank you
If you want symmetry, you could do 2 asymmetrical pieces, flip one around, butt them up against each other, and boom, symmetry. ;)
Great video. I know it’s been a while since you put this out. Not sure how thick your wood is but the piece I’m trying to do is three-quarter inch a little less. Can’t raise the blade enough to get the width I need what do you do with thinner stock to get the width ?
Philip Breau
Go across the blade at 90 degrees. If the cove is still not wide enough, you can bevel the blade. It won't create an offset cove because you're going across at 90. Only combination angles will yield offset coves. One more way is use larger diameter blade if you have access to a machine that has one.
1 second ago
I would put on my fence, set my angle gauge, and gently line my parallelogram fence off of that, over the blade.
I'm also thinking I'd make a parallelogram jig long enough to go well beyond both edges of the tablesaw so I could tighten from below. That would let you put long and thick boards through.
You took the wall out. How about a shop tour.
Even though I've seen this before, I still watch this video and all I can see are the clamps in the back.
Great! 16:24 Hey those headphones protectors are wireless? where did you get them? Thanks!
Oh, also, what if you don;t have an INCRA mitre guage? just go 30 deg. then back off just an "unta" ? Plus, My CRAFTSMAN table saw has a piece of TIN for a bevel indicator; you can bend it back-an-forth. Maybe set blade to 90 deg., set tin arrow, then lay the blade over to desired bevel? Thanks, good idea, W.W. !!
Is it okay to raise the blade while the saw is on? I always turn my saw off.
If the rails are long enough and you don't have an outfeed table, you can certainly do that. With my setup, it wouldn't work.
Rather than a bridge that interferes with the workpiece why not flip the parallelogram jig over, you could then have the connecting short pieces flush with the height of your table saw. A slot in the connecting short sides of the jig could be cut so the locking bolts can be adjusted along the length of the short sides to account for varying width in each workpiece each short side could ride on the front & back edge of the table & the jig locked parallel again using the workpiece?
Good method...
if you die before me can i have your tools please? So so jealous!!!! going to cry myself too sleep now! look after that baby.
👍
how did you find the center of the apex?
Sure is. Along with diddly-whacker and doohickie. :)
Anybody know where to get that little adjustable sanding block?
It appears to be a VarioPro Profile Sanding Block. Also check out www.finewoodworking.com/2008/10/28/greatest-hits-custom-profile-sanding-blocks for a method to make a perfect fit sanding block.
I miss the old introduction music
thank you for the video, it was interesting. I am surprised that you didn't cut slots down the center of each long rail and use those to attach them to the miter slots.
I do think though that even if you personally choose to use the sliding power miter box incorrectly I don't think you should be showing novices the wrong way. I am amazed at how many 'teachers' on tv do this very same thing. I think they are trying to mimic using a table saw but not realizing that the blade on a table saw is below the work and the leading edge is pushing down into the table where as the power miter box and radial arm saws are above the work causing the leading edge of the blade to try to lift the wood off of the table. please check out the instructions that came with the saw, ty.
I'd suggest that you take up reading..... as in manufacturers manuals, because every manufacturers manual I've ever read says that you cut on the push stroke with a sliding compound mitre saw, but hey, the Internet is full of "experts" who know better......
Why don't you just make the fence longer and put the bridges on the bottom side to allow thicker work pieces to pass through it.
Updated link to the calculator www.finewoodworking.com/online-tools/cove-angle-calculator
Could you help me please with a cove cut problem my name is Diana
eyeball the damn thing and push the wood.
I see that you only use say timber that was 12" long what would you do if you had a pice of timber that was 10 ft long i don't think your jig would be much good.
Do you ever interact with your commentors?
tmnt in this vid
calculator link is broken. finewoodworking dot com /online-tools/cove-angle-calculator
cakeller98 g
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Thanks Mark.