Milling Rough Lumber Frustrations

[Dustin Brown]

So I had a frustrating weekend. I've been working on the 21st century bench and I was finally milling up the 8/4 kiln dried hard maple for the top after acclimating several weeks in my climate controlled shop.

I jointed and planed all the rough stock friday night and sat it aside til yesterday. Everything had stayed put so I was starting to rip it down into 2-3/4" strips. By the time I was through I had several cases where the stock was pinching the riving knife so hard I couldn't force it through and had to shut everything down. Looks like I will be lucky if I can get a 2-1/2" top thickness when all is said and done.

This was very surprising to me to say the least. I was following the video and milling everything as suggested, but I was not expecting to have this much released stress and wood movement. If I had known this I would have ripped it all down first and then jointed/planed everything up. I would have saved a lot of lumber this way.

Is this to be expected? I knew I would lose some material milling everything, but did not expect losing even more after ripping it down. Should I not have even milled it up until cutting it to rough dimensions? This has been pretty frustrating, looks like I will end up with a 2 to 2-1/2" top after spending $300 on lumber, if that is even thick enough for a bench.

[Jim Foster]

Not an expert, but I have the same problems with the q-sawn or rift-sawn white Oak I'm using, it's been stickered in my shop for years and the humidity does not vary that much. I think it depends in part on the grain direction and whether it's oriented in a "reaction" kind of direction. I'm also suspicious of Kiln work these days, but not far enough along in my woodworking education to determine what's to be expected and what's not.

[Jeff Duncan]

Your dealing with stresses that are inside the wood. When you take a piece of maple that's say 6" wide, and rip in in half, if there's any internal stress inside the wood, by removing all that wood your releasing that stress. Some woods are better than others, but maple is prone to doing exactly what your describing.

Not that it will help you now, but this is how I mill 8/4 maple when I need flat stock for interior doors and such. I first cut it to length leaving at least several inches and often more depending on the length I'm starting with. I face one side and edge on the jointer just enough to have a flat reference for the planer....in other words it doesn't have to be a clean face, just mostly flat. Then I plane the stock again just getting a mostly clean face. (For clarification....on both operations I'm happy getting the stock about 80% clean or so, I want to remove as little material as possible to get the stock flat enough to safely mill in the next step. The important thing is to get it clean all the way along the length, if the edges are rough it's fine). Now I move on and rip the blanks oversize on the table saw. I know my stock is going to move so for thick stock I may leave an extra 1/4" or more depending on the sizes, and quality of stock I'm working with. Now I'll take those blanks and joint one edge straight again and re-rip to just a bit over my finished dimension. Now my stock is still oversized and still has some rough sections left on the faces but I'll try to let it sit for a day or more if I can before going back and re-doing the process to get to my finished dimensions. I will also cut closer to the finished length as I now have a better visual of the wood, and the shorter the pieces are the easier to mill.

By milling my stock this way I can get maple parts straight enough for making interior doors. It's a little more work, but well worth it to ensure your stock is going to stay straight!

As far as your current situation. I'm not familiar with your specific bench plan, but 2-1/2" seems plenty thick enough to me. I would try to orient your stock so that you can get a clean flat top with as little milling as possible, placing individual bowed pieces up if needed. If the bows face up you can remove them without losing overall top thickness. The bottom of your bench doesn't need to be perfectly flat, so if there are some boards that are shallow from being bowed up I think that's acceptable vs trying to get it flat and losing thickness;)

good luck,
JeffD

[Paul Murphy]

In addition to agreeing with what Jeff has said, I’ll go ahaed and post this reply I had been (slowly) typing:

So I had a frustrating weekend. I've been working on the 21st century bench and I was finally milling up the 8/4 kiln dried hard maple for the top after acclimating several weeks in my climate controlled shop.
Just making sure you know that wood should be stickered to better acclimate.

I jointed and planed all the rough stock friday night and sat it aside til yesterday. Everything had stayed put so I was starting to rip it down into 2-3/4" strips. By the time I was through I had several cases where the stock was pinching the riving knife so hard I couldn't force it through and had to shut everything down. Looks like I will be lucky if I can get a 2-1/2" top thickness when all is said and done.
Jointed and planed to what thickness before ripping?

This was very surprising to me to say the least. I was following the video and milling everything as suggested, but I was not expecting to have this much released stress and wood movement. If I had known this I would have ripped it all down first and then jointed/planed everything up. I would have saved a lot of lumber this way.
Yes, it would have been better to rip oversize first, acclimate, and then mill. You never know what combination of stresses are present in a given board, and the thicker the stock the greater the possible stresses.

Is this to be expected? I knew I would lose some material milling everything, but did not expect losing even more after ripping it down. Should I not have even milled it up until cutting it to rough dimensions? This has been pretty frustrating, looks like I will end up with a 2 to 2-1/2" top after spending $300 on lumber, if that is even thick enough for a bench.

Yes, this happens, and more often when you have recently acquired your thicker stock. After a while you will know what to expect from your sources, and how much oversize you should rough dimension your parts. If I had been ripping wood that reacted such as yours, I would have increased my rip dimension at the first sign of excessive movement. I too learned this lesson the hard way.
Opinions will vary, but even a 2” thick top is going to be pretty sturdy. The classic European bench had some thicker ribs and aprons, but the bulk of the top was often about 2” thick, and lots of those benches have served well for quite some time.
If it makes you feel any better, I built my first bench from a large beech I cut on the family farm, and air dried in my barn. I went through an experience similar to yours, only I had been aiming at a 2” top and ended up with a 1-3/8” top. Well, 17 years later I still use that bench and the lumber that was to be used to build its replacement has been stacked in my shop for 15 years. There was always something more important or interesting to build, and my first bench gets the job done.

[Mel Fulks]

Irritating but not unusual. We have a particularly good dealer here in that he only buys from a small group of suppliers. He buys no "deals" from strangers. Even so ,what you are describing is typical of those dense woods. I would have ripped the pieces 3/4 inches over finished size.The top will still be fine. Gluing thick ,even kiln dried, maple often opens small cracks at the glue lines over time as it loses more moisture.Look at any fine used benches and you will see that. A notable exception are the Bally brand tops. They must be gluing those in very warm dry shop. What Im saying is your top might actually be more satisfactory to you over time. Might as well look on the bright side. We moderns tend to be a lot pickier about benches than guys of old.Ive seen photographs of old shops where a top might look like it had been attacked by Lizzy Borden. In my experience the only way to assure your top won't start opening up,if that is important to you, is to make a shallow dado in the middle of each piece about one third the width of the finished top thickness. Some of the makers of two piece glued up hand rails do that ,and their stuff seem to resist those small cracks better than those without it. I have not seen even one older building with two pc glued maple or birch or beech handrail that doesn't have a hairline crack on every foot.

[Mel Fulks]

Just wanted to say ....I started my typing when there were no responses! Good advise,all.

[Carl Beckett]

This might seem controversial, but who says you need lumber that is perfectly flat and square to begin with?

For sure wood is full of internal stesses. A batch of elm I did my workbench out of was the worst I have experienced. But as long as the piece can be clamped down and glued in place, for something like a laminatd top I wouldn't try to get perfectly flat and square pieces to begin with.

This is even true to some degree on furniture. Design is key to know when, but often you can pull a piece into place and have it be perfectly functional

[Paul Murphy]

Carl, it might help to give an example. For example if I were building a bench top from 1 x 3's I might not care that they were mildly bowed...as long as I face clamped 2 boards together to cancel their equal bows and clamped them to a known flat surface. Repeat until finished, and the stresses are in equilibrium. I would not personally try to clamp bowed 3 x 3's together, those I would joint and accept that they might then be 3 x 2-1/2 or whatever.

In the end, I have the best luck assembling from 4-square parts. With that as my intent, I have my trees sawn to enable that goal and it works for me. Every now and then I have a piece that twists/bows/cups badly and it becomes smaller pieces or even firewood. I also buy some beautiful wood from one sawmill nearly 2 hours from me...worth the trip because he saws/stacks/dries the wood properly and I rarely have problems with his lumber.

As far as twist goes, I'l never try to build a drawer or a door from twisted stock.

[Carl Beckett]

Indeed, it is all relative ( of course we can ague. What 'flat/square' is in absolute values).

He has 8/4 stock that he is ripping to 2 3/4. It's bowing, etc when being ripped. It's getting glued up over an 8 ft length (guessing here). He is having to take as much as 3/4" off o get it all squar again.

For me ( and this is just me), if you could pull his down with clamps during glue up, I would be fine with doing so. Saving some of the top thickness. If only 1/2 " pulled down, I would do that then.

I would also assume that internal stress might 'anneal' over time. That is, wood is subject to creep, and over a long time might relax the internal stresses some. Also it's likely to require re flattening from time to time, even if perfectly square to begin with

My suggestion is that, especially us that use power tools a lot, we over do it 'sometimes', on getting a perfect piece to start with.

[scott vroom]

If I had known this I would have ripped it all down first and then jointed/planed everything up. I would have saved a lot of lumber this way.



I believe you have answered your own question.

[Paul Murphy]

Carl, the devil is in the details, but I would agree agree with you up to a subjective point. As to how you know the OP is working with 8/4 stock, I guess I'm hard of reading because I don't see that stated?

As to flattening the top later, yes to both methods, however the top from 4-square stock would likely require less secondary flattening and provide a more seasonably stable surface.

[Dustin Brown]

Thanks for the info guys. Seems I just didn't account for the internal stresses being released when ripping.

The stock started out at a full 8/4, ended up at about 1.5" after jointing/planing before ripping. The stock was stickered on my shelves for a few weeks before touching it. Didn't figure there would be any movement seeing as it stayed straight and level after milling.

Do you think 2.5" is thick enough? Wondering if I should try to glue some strips or something to the bottom to get some extra thickness or not. It really sucks to spend $300 on lumber and not get what you wanted. I do have a good bit of 4/4 maple I could laminate if there was another option to help get the top thicker.

[Carl Beckett]

Do you think 2.5" is thick enough? Wondering if I should try to glue some strips or something to the bottom to get some extra thickness or not. It really sucks to spend $300 on lumber and not get what you wanted. I do have a good bit of 4/4 maple I could laminate if there was another option to help get the top thicker.


Functionally, I think 2.5 is plenty. Aesthetically, or more important as you say you spent all that money and didn't get what you wanted, might be the bigger hurdle

As mentioned by others here... I have a number of projects that didn't turn out how I wanted, but are still in use many many years later. Its a question of your personal style/objectives. (some people here would redo from scratch if even the smallest thing went out of whack. That's not me, but I get why they feel that way.

Smeone recently told me; if it's a hobby and you are enjoying it, you don't want to press to get it done quickly, right?

[Mel Fulks]

Again ,that will do just fine. Most, if not all, of the expensive factory made woodworking benches have thinner tops,the thickness you see in the catalogs is just a facing. I spent more money than I needed on my top, too.Fell for the "beech is traditional thing". Relax and enjoy.

[Paul Murphy]

Dustin, 2.5" is plenty thick enough.

[Peter Quinn]

Thanks for the info guys. Seems I just didn't account for the internal stresses being released when ripping.

Some guys have spent a lot more $$$ to learn that wood moves. When splitting wider stock, particularly into narrow staves, I'd get one face flattish, one edge straight to run along the rip fence, then start ripping your parts over on width by at least 3/8" to 1/2". After the first few you may find you can cut that back to 1/4" if the batch seems stable, you may have to push it up a bit. Then rest 2 weeks now that the stuff is smaller. I would have done that the day the wood came into the shop. 2 weeks is not even close to long enough to acclimate 8/4 anything full width, just too thick to acclimate that fast, but that may not have been all your problem. Maple is not the most stable species going IME, and any thicker stock may move around on you when you disturb its equilibrium. Frankly loosing 1/4" is marginal. If you want a thicker look, just mill up a thicker skirt board for one edge and end to give your clamps more purchase, done. Lots of commercial benches are 1 3/4" with a 3 1/2" skirt, works fine. A 2 1/2" thick maple top is brutal overkill, so 2 3/4" is IMHO just a bit extra brutal overkill. Maybe with a lighter or softer wood like SYP which seems much in fashion since the Schwartz book that might make sense, but hard maple has a lot more strength and mass than that. I made mine 2" +/- , made the frame under it stout and put some heavy stuff in drawers, it can take a hit from a fork lift and not move.

Chin up I say, this is supposed to be fun! No frustration when wood defies you expectations, just get out the sugar and make lemonade!

[Bob Reda]

I don't think I ever built a panel that was perfectly flat when it was all together. There always seemed to be a piece or two out of alignment. What I do is to make panels the size of my planner, for example if i was doing a 30" wide top and have a 15" planer I would make two sections 15" in width. After drying, I would run both through the planer to make as flat as possible. You have to run both the same number of times to get equal thickness. Then I would put the 2 panels together and try to get them as flat as possible. Then use a sander, scraper or whatever to flatten after they dry.

Bob