I screwed up and need some help - Bench Top Buildup

[Patrick F Graham]

I'll just go ahead and admit it - super stupid move on my part.

Project Setup:
Building a Roubo Split Top bench, my first real bench in my life (57 years old, working with wood since at 13 in boarding school).

It's not an exact Benchcrafted version but that's not important right now (but I am using one of their Acme Screw kits - NOT in love but another story later).

I'm doing it with a HomeDepot 2x6 build up, 3-3/4" thick top, slightly dressed 2x6's to get something close to square, etc., etc. (mostly I'm doing it this way to understand the entire process so I can build a better one at another time).

So, to make top align (flat), I put #20 biscuits every 12-15" down the 6' cut board. Quick picture of last night's glue up here>
20210823_111429.jpg

So, I had to adjust the biscuit jointer to a shorter distance from the referenced top down to accommodate the thinner space near the area around the end-vice cutouts to 3/4" then back to 1" for the other 10 or so slots - 5 each.

Here's my steps, should be easy to see my HUGE dumb move:
- Using my existing 1" biscuit jointers settings, I put all 5 slots on the glued-up bench top
- Adjusted the biscuit jointer to 3/4" and slotted the 1 spot that couldn't take the 1"-er.
- Took my next piece to add to the top (shown in the pic as the top of the stack), remembering I adjusted to 3/4", I adjusted back to 1" and slotted my to my corresponding locations
- Changed the biscuit jointer to 3/4" then did the slot for that singe one.

At this point the damage is done - can you see it?

- Did the glue up, added all the clamps etc. etc., time, etc.....

The mistake is, I touched the stupid biscuit jointers height adjustment BETWEEN one side and the other - TWICE!!!!

So, now I have a slightly, 32'nd +/- board sticking up and still need to add one more board to it.

Considering each of the '2x6's are cut down exact finished height, I can't, and don't know how I can thickness plane my way out of this screw up AND don't know how to fix it so I can accurately add my last board to this 'half' of my Split Half bench top.

Any ideas about how to fix this dumb move? The bottom is to uneven to simply run through the plainer - maybe a 'carrier' for the whole section then through the plainer - I don't know - so mad at myself.

Thanks, Patrick

[Paul F Franklin]

Patrick, if this is your worse goof...well, I'd wager you have something else to look forward to cause we've all been there.

I'd say either mount it to a sled, shimming as needed, and run it through your planer, or rig up a flattening jig for the router, like folks use to flatten large slabs. Either way, I'd probably attach the last board before the flattening step. You only need to get it close (aim to have it a tad high) because it will get leveled to the others in the flattening step.

Of course, if you have hand plane skills, you could go that route; most folks do a final flattening with a hand plane anyway once all is mounted and done.

For the future, one way to avoid having to muck with the setting on the biscuit joiner is to leave it set at 1" and use a 1/4" spacer under the fence when you need 3/4.

[Steve Fish]

I admit I have never built one of these benches so I’m not sure if this will work for you. Plane it upside down on a sled with the offending board off the edge of the sled, flip it and then do the top.

[Patrick F Graham]

Photo with clamps off - light from garage door coming in from right of photo exaggerates the screw up but illustrates it for clatiety.
20210823_121627 (Medium).jpg

Damn, I'm so mad at myself!

[Patrick F Graham]

As I mentioned Steve, I've left the bottom to be whatever to deal with or not later so, I have NO flat surface to reference to - Paul's idea of a sled is maybe the only big picture fix.

I don't know, thinking, thinking...

Patrick

[Patrick F Graham]

Electric hand plane????

I don't have one, haven't for years, used them a lot for hanging doors.

I remember then to be LOUD and rather unforgiving if not set up right.

Maybe???

Mikita KP0800K 3-1/4" Planer - ~$170 ? ? ?

Patrick

[Steve Fish]

I was in agreement with Paul about using a sled. I was maybe not explaining it well. If you fix the bottom first you can then use it to reference from to fix the top using your planer. Or do you not have a planer?
edit; of course you do, I see a nice Jet unit in your last picture. This video is somewhat close to what I was suggesting. Your evenly glued boards would be substituted for the partially jointed board
https://www.youtube.com/watch?v=vzmSjlXJ2fg

[Bryan Lisowski]

Couple questions. 1) is this the bottom? 2) is the other side flat? If the answers to both are yes, you could pour epoxy along the mess up. Then you can sand or send through the planer. I had this happen when I glued mine up, partly because I didn’t use biscuits or dominos, so I got some creep. With the epoxy being on the bottom nobody will see.

[Mike Rambour]

Its only a little bit that you have work with, I would make up a slab flattening jig and hit it with that. I know you said the boards are already at finished dimension but I would make a new finish dimension and flatten it.

[Scott Winners]

I think I wound put the last board on, positioned so the bottom of the bench will be as flat as possible. You will have a little valley in the bottom however deep, but other wise "flat" all the way round the perimeter and most of the field.

Then you could run it through your thickness planer bottom side down to flatten the top, and then if you must (I don't know your undercarriage joinery) flip the slab again and flatten the bottom.

The "flaw" you have pictured is pretty minor as bench tops go. With a properly tuned scrub plane that would be a ten minute job. Buying a plane and then turning it into a scrub plane and the tuning it as a scrub plane; use the power planer your got, it will be faster and less work. I see being able to run the two slabs through a thickness planer as one very attractive element of the split top design.

[Derek Cohen]

Patrick, a hand plane would take that down in a few minutes. A Stanley #5 is designed to do this.

Regards from Perth

Derek

[Richard Coers]

Personally, I think your first screw up was buying Home Depot 2x6s. With recent prices you could have purchased hard maple from a lumber dealer for less money. But most importantly, you would have material dried to 6-8% instead of 19+%. I'm working on the bench I made 40 years ago.
workbench.jpeg

[Myk Rian]

Run the top over the table saw and cut the board off. Then redo it.

[John Kananis]

I agree with those that said use a hand plane (#5, #7, take your pick). That's really not bad at all and don't worry about the lost thickness, 3.5" is very substantial - if anything, hold fasts will sometimes hold better on less than 3.5 inches.

[Patrick F Graham]

Alright - this site is AMAZING!

I took a couple bits from Paul, Mike, Scott, Derek, etc.

So, what I took was to get back to flat then deal with the 'bump'.

This is a picture of the benchtop on it's side, illustrating the problem and the 'fix'.
20210824_145956 (Medium).jpg

I decided to use my biscuit jointer set at 1" depth and cut slots on the glued-up portion of the benchtop, offset the next board to be below the mistake by exactly the same amount then run it through my Jet 13" planer or use a hand plane (#5, #6, etc.) to flatten out the bump.

Steps:
- After getting over the fear and reading everything you guys contributed, I reset my Dewalt biscuit jointer (not a particularly precise tool, sadly) to 1" > doesn't matter what I set it to since it's going to work with the new dimensioned 2x6 to be added.

- I slotted the glued-up side first - all the way.

- Then, I took a sharp scrap (fully square) and made the same slot on one end > picture
20210823_233056 (Medium).jpg
Marked from L to R - Test #3, Test #2, Test #1, Matching

- I started adjusting the biscuit jointer (in my case down) shallower then mad a test slot, add a biscuit and test it against the glued-up benchtop using a killer Skarrett 6" Double (first time I EVER measured in 64ths).

- Once I got it, 3rd try - I cut corresponding slots on the new board. The mistake was 5/64ths.

- Glue up - L to R - Top, Bottom
20210824_115911 (Medium).jpg 20210824_122058 (Medium).jpg

The first picture at the top is what's in the clamps now - pretty darn (I hate the word, but....) close.

I'll pop the clamps around 6 tonight (PST) - 5 hrs of cure time, see how she looks.

Then, taking more advice, I'll give up on target dimension thickness and see if I can run it through the planer bottom side down first to remove the mistake. Maybe one tiny pass flipped, maybe, just to clean it up, or wait to add my last board for this section of the bench top.

I'll post the after clamp pictures and post planer pics tonight.

QUICK NOTE on why the thickness is important - I bought the Benchcrafted tail vice and it's SOOOOOO complicated to install - overly complicated (more at another time, another thread). The key dimension among all the the key must not change dimensions is the thickness of the base. Anyway, I know why they want it that way and stuff like that.....

- Patrick