What thickness do I buy

[ken antoszek]

Hello, I want to start building some furniture for the first time and have a question about wood thickness. Plans call for 3/4" and 1" material, do I buy 4/4 and 5/4 or should I move up to 5/4 and 6/4 respectfully? I have the tools to mill the lumber but 1/16" leeway doesn't give me much room to work with. I hope I made sense in what I am asking.

Thank you, Ken

[Tom Dixon]

5/4 = 1 1/4" and normally is milled to 1". 4/4 is 1" and is normally milled to 3/4". I would not be wasteful and up size to 6/4 and 5/4. You have 1/4 of waste already. No need to throw away 1/2".

[Mark Rainey]

4/4 from a good supplier is over 1 inch throughout. Look over the boards carefully for bow, cup & twist. Often I can get 7/8 or more finished from 4/4. It should be fine for 3/4 final. The same for 5/4. It should be at least 1 1/4 & from a good supplier a little fat over that. That is fine for 1 inch final.

[glenn bradley]

Not sure where you are Ken but, I'll kick in with what I find on the southern west coast. 4/4 is a skinny 15/16 but, with careful selection I have gotten "parts" that are 7/8" with 3/4" being no problem. The reason I put "parts" in quotes is that one may be able to get 7/8" pieces out of some areas of a board but, other areas due to defects may yield thinner stock. This assumes you want your parts true and square.

5/4 will yield 1" to 1-1/8" finished parts. My preferred yard has the species I use in 10' to 12' lengths as a rule. It is important to look at boards not as boards but, as a blank that you can get "X" number of parts out of. Figure, or the lack thereof can contribute to what parts you get from a given board. When in doubt I prefer to pay for a little more material, thickness-wise or otherwise, rather than try to go back and match something that is 90% done because I goobered a cut.

[Jared Sankovich]

Really depends on the mill and supplier. I can net 1.00" for moulding for a 10' stick of the 4/4 soft maple or poplar from my local yard if I'm careful. My face frames and cabinet doors are 1.155" and I dont have any issues getting that from 5/4.

[ken antoszek]

First off, thank you for reading and responding to my question. I think I should have supplied a little bit more information to my initial post.

The furniture plans call for parts/boards to be 3/4" and 1" thick. My local yard has SBS 4/4 that measures 13/16 and SBS 5/4 that's 1 1/16. Does that change any of the answers given so far?

Thank you, Ken

[Mark Rainey]

Ken, I assume you mean S4S, which is jointed, planed & ripped to width. It should work for you, but look over the boards very carefully. Wood moves, and over time your boards can cup, twist or bow. That is how I got into hand tools. I bought premilled poplar & began my project a couple weeks later. The boards were not flat. An old timer told me about a jack plane.

[Lee Schierer]

It depends on how much labor you want to devote to the project. Milling your own materials adds a lot of time to a project. If you have a good source where you can purchase kiln dried S4S lumber of the type you need, you can start cutting pieces as soon as you get it home. I'm fortunate that I have two suppliers in my area that supply S4S hardwoods for very reasonable prices. Their quality is excellent and I can often select the highly figured pieces from their inventory as they supply to the local contractors who don't care for the highly figured wood.

[Thomas McCurnin]

Glen is correct that after planing and sanding you’ll get something around 7/8” from 4-4. You’ll get 1 1/8” from 5-4.

if you want to be slavish to the plans, then have your supplier mill it down to 3/4 and 1” after sanding to 100g, both sides. You won’t waste much. Make sure he joints one edge and not obvious what edge it is, Mark it with blue tape.

I think exact plan sizes are over-rated. You can adjust the height width and depth to suit your needs or to match the stock you are using. I use plans for design and instructions on how to mill and assemble. That’s actually the fun revising the plans.

[ken antoszek]

Thank you for the inputs/answers, I seem to suffer from anal retentiveness.

Ken

[Don Stephan]

My experience is that rough cut lumber is never flat and straight. S4S boards from the local lumberyard have smooth surfaces, but are also not flat and straight. Yes, clamps can pull pieces of wood flat and straight, but when the clamps are removed the pieces try to return to their resting states. The local hardwood lumber yard "surfaces" rough sawn boards using a machine they call a molding machine, that planes both surfaces simultaneously, so it does not remove twist.

Making a board flat and straight starts with making one surface flat, either with hand plane or careful use of a jointer. A power planer makes the top surface smooth and parallel to the lower surface, so a power planer will make a twisted board into a slightly thinner twisted board.

My experience is that making a "fairly straight" rough sawn piece of wood no longer than about 42" flat abd straight can take up to in extreme cases 1/4" of thickness, and longer pieces of wood more thickness.

[Steve Jenkins]

Also to help maximize thickness rough cut length of parts prior to any milling. I usually cut 1/2 to 1” long after cutting off all end checks.

[Andrew More]

The length of the parts is also going to have some effect. If you're attempting to mill 6" flat it's going to be easier than 6'. At 6' even the tiniest curve can result in needing to mill off quite a bit of material to flatten the board. At 6" not so much. Generally as a result it makes sense to rough cut parts down on the band saw, or circular saw before milling. Don't attempt to do this with a table saw, since it's more likely to bind if it's twisted cupped or bowed.