Sign in to follow this  
applejackson

Tapered cove on table saw

Recommended Posts

Does anyone have specifics on how to taper a cove on a table saw?

I understand the approach but my best guesses on the curvature of the auxillary, over-the-blade fence, and the cleat tacked to the work piece that rides that fence, aren't getting me close. 

If anyone has successfully performed this cut, I'd sure love to hear about the specifics.

(I'm aware that a bearing guided cove bit is another approach. I'm only interested in doing this on the table saw. Thanks)

Share this post


Link to post
Share on other sites

Do you mean like the coves on these bracket feet? They were done on a TS using two boards one on each side of the piece I was coving. To change the cove you change the angle that you push the blocks through the blade. Not sure if this is what you are looking for or not.

IMG_3540.JPG.26b00540ffdbff29821003ec86466457.JPG

IMG_3541.JPG.8adbb0337c0bf4d1b9aa9763882c0955.JPG

  • Thanks 1

Share this post


Link to post
Share on other sites

Can you clarify? By tapered cove, do you actually mean one that is deeper / wider at one end of the board than at the other?

If that is the case, your fence(s) on the saw must have a ramp or taper on top. Attach a block at the 'shallow end' of the piece being coved, such that it begins to engage the ramped edges of the fences at the point where you want the cove to begin getting shallower. This will cause the trailing end of the piece to be pulled up, away from the blade, as it is pushed along, resulting in a tapered cove.

Be sure the piece is rigid enough to not flex as it loses support from the saw table. A poor cove , or a nasty kickback could result. You could attach a 'strongback' with double-stick tape, to remedy any flex.

  • Thanks 1

Share this post


Link to post
Share on other sites

Sorry I am late on the reply guys. I want a cove as a profile on the long end of a panel, tapering to an end about 2" shy of the short sides. I'll post a pic.

Share this post


Link to post
Share on other sites

here is a bad picture that conveys what I am trying for. The cove, cut as a profile into the panel, needs to taper down to nothing, stopping just short of the short sides of the panel (the short sides will feature a full cove profile). 

NOTE: this pic is not my workpiece. It is just a pic of a panel that I drew on to try and convey what I am asking.

 

Thank you in advance. 

panel w taper.jpg

Share this post


Link to post
Share on other sites

Looks like it would need a curved fence set diagonal to the tablesaw blade. Much trial & error would be required, especially the error side of the equation.

  • Thanks 1

Share this post


Link to post
Share on other sites

@wdwerker that is EXACTLY right - the problem is that my trial and error isn't getting me close. I dont have feel for that curved fence (that has to sit over the blade, incidently). I have cut 4 curved fences and gained a lot of firewood, but I am not there yet. 

It is a very specific effect so I am kind of shooting in the dark in hoping someone else has done it. But it never hurts to ask. 

 

Thank you for your reply !

Share this post


Link to post
Share on other sites

@pkinneb those are some beautiful looking feet. But I think what you cut is a straight, consistent cove when you made them. Sorry, my first description wasn't very good. It's hard for me to describe in words, hopefully the picture helps. 

 

 

Share this post


Link to post
Share on other sites

MDF is cheap !  It just might be that you need a section of a oval instead of a segment of a circle. Many years ago I built a jig to cut oval shapes with a router. I expanded on plans for a 2' x 4' Jig and made made one with a 8' arm which would make a  14' x 16' oval , or smaller  down to around 4' x 8' ovals for conference tables.  It's based on a  " X " shaped dovetail groove in a baseplate that guides the arm with a router on the end. There is probably some math to calculate the rise and run of the oval segment but if I understood that level math I wouldn't be a professional woodworker !

Maybe a bent thin strip that would cross the width of your panel x the desired change in height of the cove cut could be an easier way to create the curved fence you need. 

Warning ! Cutting coves on a tablesaw is definitely risky behavior ! Cutting curved coves on a tablesaw might be possible but it is definitely dangerous behavior.  If you try it please post the results.... hospital or raised panel would be informative and or entertaining !

Share this post


Link to post
Share on other sites
6 minutes ago, wdwerker said:

...Cutting curved coves on a tablesaw might be possible but it is definitely dangerous behavior...

In my opinion this is asking for trouble I would strongly suggest for you own safety you find another way. If you do choose to proceed I hope you have a sawstop and a face shield. I think kickback would be a likely result. 

Share this post


Link to post
Share on other sites

The explanation at the hospital would be entertaining I think. A pair of Grrripppers might avert the need for surgery.........

Share this post


Link to post
Share on other sites

I don't know if it's possible to do this with a curved fence.  Won't the curve change the angle the panel makes with the blade which will change the cove?

One option to get close might be to make each pass stopped.  As you raise the blade for each shallow pass you start and stop closer in, which will taper the cove towards the ends.  It will take a lot of handwork to clean it up after but it would be straightforward to do with a set of marks on the fence.

Share this post


Link to post
Share on other sites

Maybe you need to find someone in your neck of the wood that can do it on a CNC.  Probably a lot safer too.

Share this post


Link to post
Share on other sites

If you want to cut a curved cove on a straight piece, I think you would need a two-piece curved fence. One piece would be attached to the back of the work piece, the other to the saw table, and elevated to match the height of the first one. The mating curves should carry the workpiece through the cut as a bearing does for a router bit.

For the curve you described, the fences should be arranged to form a "smile" as viewed from the operator's side of the saw.

Now, this will only work well with a smooth curve. If I read your description literally, I think you want something more like @krtwood  mentioned. A "stopped" cut might work, or you might use opposing wedges on the fence to direct the ends of the workpiece away from the blade at the ends of the cut.

Each method will get close to what you want (I think), but will yeild slightly different results.

Now you have me thinking of interesting ways to modify a cove .....

And please take the safety warning seriously. Tablesaw coves can be done safely, but you must be patient and use your head. Small bites.

Share this post


Link to post
Share on other sites

If you’re that gung-ho about the design, I would use a combo of rasps and card scrapers to get there. 

Share this post


Link to post
Share on other sites

@wtnhighlander that's exactly right. There's a convex fence set over the blade and a mating cleat fastened to the work piece. 

I've seen this done in this way. My trouble is in creating that fence. I don't know the length, or the concavity (not sure if that's a real word?).

I also don't know the correct angle of approach to the blade. 

 

I appreciate the safety warnings. I've been working on this for several weeks now, so far so good, in that I've been safe.

 

I appreciate all of the answers/advice/concern. 

 

 

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Who's Online   2 Members, 0 Anonymous, 47 Guests (See full list)

  • Forum Statistics

    27,496
    Total Topics
    366,936
    Total Posts
  • Member Statistics

    20,682
    Total Members
    1,529
    Most Online
    gregcooper669
    Newest Member
    gregcooper669
    Joined