How much material to buy for a project?

[George Bokros]

I know how many bdft the calcs show I will need for the project. My question is how much extra I should buy. It is a simple built in bookcase. I am excluding the plywood I will be purchasing later for the lower cabinet boxes.

Some say 10%, some say 20%, some say as much as 50%. I do not want a bunch of left over, I have enough of that kind from past projects.

Thanks

[Dave Mount]

There is no single answer. It depends.

It depends on how carefully you match your board sizes to your cutlist. Just saying xx bf doesn't say much if you buy a 7" board and rip 5" wide pieces out it with nothing to do with the offcut. Same thing if you need 6' pieces and all the boards are 8' long.

It depends on how many defects there are in the material (currently visible and those you discover when breaking the material down) and how carefully you are planning your cuts around them.

It depends on whether you cut your pieces out oversize and let them stabilize before milling them to final dimension.

It depends on how you figure your needs. If you need a piece that's 1.5" by 6', is that 0.75 bf or is it 1 bf?

It depends on how worried you are about grain placement and orientation -- if you're picking out all rift sawn material for stiles and rails so you don't have grain arches that don't mesh aesthetically, you might need more because you're discarding some flatsawn portions of boards. Are you cutting around sapwood?

It depends on what you're making. What it takes to make a table top is pretty easy to project when you have a pile of boards to choose from. For more complex projects, it may be harder to connect.

It depends on whether you're buying random width material or material that's S4S so you know exactly what you're getting.

For that matter, it depends on how your supplier scales lumber. Some scale in a broad way ("oh, you've got three layers that average 3' by 7' so lets say 63 bf"; often these types allow a fair amount of overage) and some measure every piece to the quarter inch, and then round up. Some suppliers won't even let you pick your own boards, though I wouldn't buy from them unless you are buying large quantities on spec, and the price you're paying reflects the additional waste you are likely to experience from material that you probably wouldn't have otherwise taken home.

When I pick lumber for a project, I start by finding the boards that will be the "show" pieces -- the table top, the door panels, the crest rail, the drawer fronts, whatever are going to be the pieces people "see" when they look at the finished piece. Once I have those, I look at whether the offcuts from those boards will make anything useful, then figure the minor components from there. I don't go in to buy X bf of lumber. I'm not saying doing it by bf is wrong, just not how I go about it.

I'm not making light of your question. I'm just saying, "it depends". . .because it does.

Best,

Dave

[Jim Dwight]

Dave is right. I will just say that 10% is a good rough MINIMUM to get. If you can plan out your pieces you might be able to get by with 10%. But you probably want to get more, especially if you do not plan which board will go where. 50% is nice, it leaves some for the next project unless things really go badly.

What I generally do is figure out what I think I need and then buy extra, maybe as much as 50% extra, so I don't have to go back and because I like having some left over. But if it was wood I didn't think I could use for a later project I might plan it out board by board.

[Jim Becker]

So many variables as noted above...including species. I'd personally ALWAYS rather over buy than have to return to a supplier and hope I can get material that's compatible with what I already bought for color and grain matching. Extra material never goes bad and gets used at some point anyway.

[johnny means]

IMO, 10% is laughably low. That's almost assuming no waste, save for trimming the ends and edges. I use +25% as a starting point for less picky jobs and move up from there.

[Rod Sheridan]

I know how many bdft the calcs show I will need for the project. My question is how much extra I should buy. It is a simple built in bookcase. I am excluding the plywood I will be purchasing later for the lower cabinet boxes.

Some say 10%, some say 20%, some say as much as 50%. I do not want a bunch of left over, I have enough of that kind from past projects.

Thanks

Dave gave a very complete account of how wood is actually used when you're making something.

Here's a few more comments

1) if your planer has snipe, you'll lose at a minimum 5% of your material, realistically 10 to 15% as you'll be cutting and planing multiple components per board

2) Jointing and planing will take somewhere around 25% of the material (for example you'll plane 4/4 stock to 3/4. (note that you can ignore this if you're making furniture, you can't ignore it if you're selling the product by volume).

3) selecting for grain and culling defects can take 10 to 25% of the material.

In my projects I normally purchase 25 to 50% more material than I use in the project.......................Regards, Rod.

[Matt Day]

A lot more. I usually go roughly 50% more to have extra stock in case of a mistake or to make sure I have good color matching. Also is nice to fill up the wood racks a bit for other projects.

[George Bokros]

Thanks for all the insights. I had not considered what the supplier might have at the time. Grain has to be a strong consideration especially when using red oak.

Again thanks for all the insight.

[Bruce Lowekamp]

If it's a wood you're going to use over and over in multiple projects, I wouldn't worry about the extra at all, make sure you have at least 50% extra so you can pick out the nice pieces and have extra for the rest.

If it was something for a one-off project, maybe Hickory or Butternut, I'd be a lot more careful planning out the cutlist. But even then, you have to assume you might make a mistake and need some extra.

I always have a supply of poplar (for painted/utility) and cherry. I think right now I only have one board of walnut and some scraps of hard maple. Used to keep a lot of SYP around but haven't made anything with it in quite a few years so it's almost all gone.

Bruce

[Robert Engel]

When grain is important, there are many things to consider such as does the grain need to flow from one part to another? is there a part like a drawer front or top, which you want more figure or a bulls eye cathedral? this can create more waste than you expect.

It may be important to have rift sawn boards, for example, door rails and stiles.

My suggestion is to have these things in mind and take a drawing of your parts. It can get quite confusing depending on the number of parts. It can help to label the part #'s on the boards and cross of the list as you go.

That is, until you discover another board in the stack that looks better LOL.

[Ron Selzer]

Dave covered it very well
I buy at a large scale wholesaler in small quantities (300-5000bdft). I place my order and they get it ready, skip planed to 15/16", bundled together. Random length They also have a room where I can buy individual boards at a higher price. Got some beautiful rift sawn white oak 14' from them 5yrs ago that had been sitting around for too long, $2.xx a bdft. Stil have some left over. Way high now to buy until I have a specific need. have been buying 4&5' cherry for the last couple of years and always picking up some popular for whatever. i do have enough room to store 200-300 in basement shop and another 500+ in another basement room. 1000 bd ft starts to get a little tight and not spread out enough to sort like I want to. Strictly a hobby shop building furniture for wife, kids and grandkids. It is nice to go down with grandkids, wife or kids and have them pick out the boards they want me to use for the focal points of the project. Kept my 15yr old grand daughter interested in a small bookcase build 30" wide 4' tall by having her pickout and layout all boards for the bookcase. She even helped with the glue up. She had over 10 knots in the bookcase. Me i would have none. Just nice to have plenty of wood to chose from, however I understand it does take room.
Just got thru making a down sized dresser for 8yo granddaughter out of solid cherry, only to have her mother paint it. Would have been a waste to spent a lot of time selecting and matching grain patterns. Still thought it would have looked nice finished natural.
Ron

[Don Jarvie]

I have no system but will by a few extra boards just in case. If it’s a wood I use fairly regularly I buy as much as my budget allow since the supplier is an hour away.

[roger wiegand]

Dave covered it. I take a different approach, which is when I see unusually nice lumber I buy it. After a while a project evolves where that wood is a good fit-- then I just hope I have enough on hand. I don't use much other than maple, cherry, poplar, and walnut so there's not a lot of oddball stuff in storage and whatever I get will, sooner or later, be used. I can also sometimes get a better price when buying a couple hundred board feet at a time.

[Dave Cav]

I generally buy at least 30% more if I'm hand selecting the material, and as much as 50% if I'm ordering it delivered in.

[Mike Nolan]

When making a Christmas present for my daughter I bought 200% over the needed board feet. After cutting to length and width and around defects I still had a generous amount. But after I lined up boards with grain matching that I liked I had barely enough.
During the shutdown I am using up my leftovers.