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Building my Workbench #6: Do these sticks make my slab look flat?

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Blog entry by HokieKen posted 11-10-2016 01:22 PM 1094 reads 0 times favorited 3 comments Add to Favorites Watch
« Part 5: It's Knot So Bad Part 6 of Building my Workbench series Part 7: Brief update and vise opinion solicitations »

Oh dear… What is he doing? Is this the second entry in a single week? Yes, yes it is :-)

I got a couple of free hours last night so decided to sneak in a little bench work. I decided I was going to flatten the slab I glued up over the weekend. But wait, aren’t you supposed to wait until the bench is done to flatten it? Well, yes. And I didn’t completely flatten it, that will be when I finish the build. But, my thinking is that this is the bulk of my top. Once I dimension one more timber, I’ll glue it with some spacers to this slab. The render below shows the final top with the lighter pieces being what’s left to be added.

So, I think flattening this now and leaving the rest slightly proud at final glue up will allow me to just plane the back down flush and give better flatness than flattening the whole thing at once. Then, I’ll do a final “shave” with a jointer plane followed by a smoother to finish it off in earnest.

So, here is how I flattened it…

It was fairly flat to begin with but, the middle was a bit high after glue-up. I would have much preferred the middle to be a little low but, it was what it was.

The front section seemed to be the better reference to start with so I laid a straight edge across the slab making sure it was contacting the front edge and marked with a pencil everywhere it touched. This left marks showing all the high points that needed to be planed down.

Before I marked out with the straight edge, I ran my jack down the glue line a few swipes to even the 2 pieces up. Then I worked in 24” sections marking lines and working straight across the grain with the plane.

I took me a little less than an hour to get it flattened across the width. At that point, it made sense to check for twist so that I could straighten it out before the next round of planing. So, out came the winding sticks I made in a previous entry. I am soooooo glad I took an afternoon to make those guys! I laid one across the right side to use as a reference and starting at the far end, checked the wind and marked the high spots. It’s hard to get a good picture of the sticks in action but I think this one shows the obvious twist at the far end.

It turned out that there was little-to-no twist along the majority of the slab. It started with a little bit about 36” from the far end and got progressively worse up to the end. I marked the high side with “H” being a lot of twist and “h” being just a little.

Rather than straightening the twist going cross-grain, I decided to just work it out during the next stage which was working at 45 degrees to the grain with the jack plane. When I got to the twisted section, I just took an extra pass on the high side of the slab on each pass.

I worked down the full length of the slab in one direction and then worked down it again in the direction perpendicular. I continued to do so until I was taking shavings at almost every point on the slab.

One thing worth mentioning: After the first 2 passes, I found I was actually creating a “hump” in the middle. It was slight but it was there. I had to really focus on making sure all of the pressure was on the front of plane at the beginning of the cut, even pressure on front and back during the middle of the cut, and all of the pressure on the back at the end of the cut. Even slight pressure on the tote at the beginning of the cut caused me to be cutting “uphill” and any pressure on the knob at the end caused “downhill” cutting. It was almost like I had to try to cut a hollow in the center to end up with a flat cut. 2 more passes pretty well evened out the “hump” I had formed.

It took me about 45 minutes and 8 passes (4 in each direction) to get consistent shavings down the full length of the slab. Then I switched to my jointer plane and repeated the process.

It’s surprising how much different the feel of the jointer is than the jack. The extra 8” really makes a difference. I was getting full shavings with the jack but, it took a couple of passes before I was peeling shavings all the way across with the jointer.

It’s also worth noting (as I think I did in the last entry) that parrafin wax is probably the greatest substance on earth ;-) I didn’t apply any initially and the extra size on the jointer really adds a lot of friction. I was getting a bit tuckered after the first 2 passes. I rubbed a little wax on the sole and it was like Chevy Chase’s sled in “Christmas Vacation”.

3 passes in each direction did the trick with the jointer. It only took 20 minutes or so since the jack plane had done the heavy lifting.

I went back down the full length spot-checking across the width with the straight edge and took a couple swipes in a few spots to flatten a hump in the center. Then I put the winding sticks back on.

It was pretty good. Still a little twist at the far end. The 2 knots make it kind of hard to get a real good, consistent swipe across the width in that area. I may try to straighten it out but, it’s pretty minor and that section will be on the front left of the bench which is where I keep my layout tools so most likely I’ll just leave it as-is.

I don’t have a real good way to gauge the flatness length-wise. Checking in sections doesn’t show any obvious issues and eyeballing it looks darned-near perfect. I wish I had a reliable, long straight-edge but a 48” drywall square is as good as I have and it ain’t great. I’m probably being overly-anal about it anyway. If it’s flat enough that I can’t detect a problem, It’s a pretty safe assumption that it’s flat enough to suit its purpose.

So, now the front slab of my benchtop is flat. I’m glad I went ahead and did it, it instills some confidence to know that I can get it done with hand planes ‘cause I wasn’t at all sure I was capable to start with. It just took a little reading about how other people do it and developing my own methodical approach though and now my worries about that part of the build are greatly alleviated. Now if I could just say the same about chopping mortises in this wood…

The best part about last night’s exercise is that these were all the tools I used to flatten it:

No cords on any of them!

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



3 comments so far

View JimDaddyO's profile

JimDaddyO

578 posts in 3285 days


#1 posted 11-10-2016 02:24 PM

Looks like you got your exercise for the day. Looking good!

-- my blog: http://watertoneworkshop.blogspot.ca/ my You Tube channel: https://www.youtube.com/channel/UCA5AretE3xPoVDV61AxUdUA?view_as=subscriber

View Ron Aylor's profile

Ron Aylor

2649 posts in 853 days


#2 posted 11-10-2016 03:13 PM

Way to go! I look forward to seeing this completed. What color are you going to paint it? LOL!

View HokieKen's profile

HokieKen

7190 posts in 1344 days


#3 posted 11-10-2016 07:28 PM



Way to go! I look forward to seeing this completed. What color are you going to paint it? LOL!

- Ron Aylor

Red of course, that way blood doesn’t show up ;)

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

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