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Floating shelf edges

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Forum topic by willhime posted 09-21-2018 03:45 PM 437 views 0 times favorited 10 replies Add to Favorites Watch
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willhime

122 posts in 1683 days


09-21-2018 03:45 PM

Topic tags/keywords: jig question resource tip trick joining finishing

I’m trying to make (3) 12’ floating shelves. So I made (3) 8’ ones and (3) 4’ ones and plan on biscuiting and reinforcing the inside joining areas to pull them together for hopefully a seamless 12’ shelf. The problem I’m running into is how to cut the joining edges clean and square. It’s about 3/4” thicker than the height of my table saw blade so after running the across that then flipping, I attempted the cuts on my radial saw but that just chewed up the edges. I then attempted it on my miter saw with a stop in place but went south as well. Is there a good way to cut the edges clean and square that I’m not thinking of ?

-- Burn your fire for no witness


10 replies so far

View HokieKen's profile

HokieKen

6271 posts in 1283 days


#1 posted 09-21-2018 05:36 PM

If your sled/miter gauge is square to the blade ad your blade is square to the table, you should be able to do this on the table saw. The only other thing that comes to mind is if you aren’t taking enough of a cut to fully envelope the blade (in other words, just skimming the end) the blade may be flexing enough to leave an un-flat surface.

Only other suggestion would be to do it on the band saw.

-- Kenny, SW VA, Go Hokies!!!

View RobS888's profile

RobS888

2490 posts in 1989 days


#2 posted 09-21-2018 05:43 PM

Wouldn’t the edge be the most important part for the seamless look? If so could you cut them with the small front side down, like a U shape then cut the otheside with the blade barely above 3/4”

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

View Matchew's profile

Matchew

1 post in 27 days


#3 posted 09-21-2018 07:31 PM

Sandwich a piece of scrap thick enough to fill the void and go back to your miter saw. I’ve done this before for a similar application.

View BFamous's profile

BFamous

166 posts in 265 days


#4 posted 09-22-2018 12:37 AM


Sandwich a piece of scrap thick enough to fill the void and go back to your miter saw. I ve done this before for a similar application.

- Matchew

This is exactly what I was thinking… Why are you trying to cut them while they are flapping without support? Pack them with some sacrificial scrap and you should be fine cutting them on the radial saw if you put a good blade in it. You probably also want to use a zero clearance insert to prevent tear out from the blade, or at worst, use some tape to hold reduce the tear out… You are cutting plywood, so you need to treat it as such…

Oh, and one last idea… You could have just done standard butt or lap joints on the corners instead of miters, and then planned to just run some laminate down the full 12’ length… You still could do the laminate. That hide the joints better than any cut you ever make because the grain pattern won’t line up perfectly…

-- Brian Famous :: Charlotte, NC :: http://www.FamousArtisan.com

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willhime

122 posts in 1683 days


#5 posted 09-22-2018 05:34 AM

yeah, I kind of feared that the unsupported open side was effecting the quality of precision cutting. I wanted to either stain them or use gel stain so I was going for a flawless look. I didn’t even think about blade deflection on trying to cut a gnat’s eyelash off but that is probably a contributing factor as well.

-- Burn your fire for no witness

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Peteybadboy

464 posts in 2094 days


#6 posted 09-22-2018 10:20 AM

Add a blade stiffener ? I have one from Forrest for about 37 bucks

-- Petey

View Kazooman's profile

Kazooman

1144 posts in 2096 days


#7 posted 09-22-2018 05:22 PM

You could do this well with a simple jig and a router. First, I agree, make a block to insert to stiffen the piece. Then make a U-shaped jig that that mimics your profile and sized to fit snugly on your form. Be careful to get the two long sides parallel to each other and perpendicular to the shorter front piece. This edge will be used to guide the router. Put a straight bit in the router and clamp your jig on the shelf the proper distance from the end so that it will guide the router bit along the edge you want to get perfectly straight.

Hard to describe, but I think you should get the idea. I would try to make a crude drawing, but I am sitting in a hotel in Valletta, Malta.

View Lazyman's profile (online now)

Lazyman

2520 posts in 1532 days


#8 posted 09-23-2018 12:17 AM

I think you’ve got a couple of different problems going on here. When chipout is a problem, especially on plywood, try making a first pass just scoring the surface. The blade should be set just deep enough to cut through the surface veneer and into the layer beneath it. After the scoring cut, you can raise the blade to the maximum height needed for the cut. On the miter saw, make a scoring pass across the top, pulling toward you and them make a deeper cut pushing away from you. Try this with a piece of scrap plywood to see how this works. A scoring cut works very well with a handheld circular saw as well.

I think the problem you are having on the table saw is a function of how long these pieces are. First, you obviously need to make sure the blade is at a perfect 90° to both table and your miter gauge. With pieces that long, you need a way to make sure that the piece stays flat on the top and flat against the miter fence. Instead of using the miter gauge, a long cross cut sled for your table saw might help make sure that it stays square to the blade as you move it across the table. It might help if your sled is large enough that you can clamp the piece down while you cut.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Kazooman's profile

Kazooman

1144 posts in 2096 days


#9 posted 09-23-2018 06:58 AM

One more thought, although it is too late for your project. Unless there was a reason to make the pieces in eight and four foot sections (transport to a job site for example) I would not have made all three joints align in one spot. Having the joint in the top at four feet from one end, the front piece joint at six feet and the bottom joint at eight feet would give a bit more intrinsic strength. It would have also eliminated the problem you are having with squaring up the ends on your large pieces.

View Sailsnsaws's profile

Sailsnsaws

11 posts in 1413 days


#10 posted 09-24-2018 03:46 PM

Some good suggestions here about how to make a clean cut through this situation.
I think you are optimistic about making a joint clean enough not to catch your eye when finished with a clear coat.
Maybe too late for this project but allow me to suggest another approach to making 12’ floating shelves.
I would have started with a couple of 12’ lengths of 4/4 stock. One for the front edge and one narrower to form a back but recessed inside the box to accommodate your floating hardware. Use your biscuit joiner to butt joint the plywood pieces to the front and sandwich the back piece inside while clamping it all up. It will be very strong and the leading edge will be seamless. I see your nice miter joint there and you could do that with the solid stock but it’s is ambitious to try it over 12’. The advantage of the butt joint is you can ease the sharp edges without risk of going through the veneer. For an even tighter fit rip your 4/4 one sixteenth wider than needed and set your joiner to cut the slots 1/32” lower for the front. This way your front edge will have a slight lip and will hide any unevenness in your glue up. Then take a router with a flush trim bit and cut it to size.
No biscuit joiner or Domino,but have a table saw? Spline joints.

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