Re-Milling S4S Lumber? Perfection, Spearguns, and Other things

All depends how bad the wood is twisted or if it's straight and flat and if it's all the same thickness. Some s4s I have used I went right to work with it. No milling was needed. 

Too many variables: what kind of wood; how it was stored including whether it was stickered, in a consistent weather environment, and getting air circulation.
Also depends on what you’re project requires: a bowed 8’ board might not be a problem for a small box or cabinet. And, if it’s for the shop or somewhere where it’s not fine furniture, you might not need to worry about a little imperfection.

S4S as sold to end consumer is actually very rarely anywhere near S4S done on a jointer, TS, and planer. Yes it is "surfaced" but more often what is also known as skip planed. Because of all the variables that can make it go to Crapsville if/when it sits unused for a period of time. This is my experience in 60 years of using hardwoods anyhow. 

Thanks for all the replies everyone! Especially as per @GeorgeWest ‘s reply, I’m realizing it might be a lot easier for me to just state my project specifics and get your thoughts from there.

For my upcoming project of building my own spearguns using teak, I won’t be using singular pieces of teak- instead, it’s multiple pieces I’ll be epoxying together into a laminated blank. This is the norm for teak speargun builds, since laminating allows you to run the grain direction opposite in adjacent boards which counteracts warping/expansion forces  that are likely, given that this will be frequently submerged in saltwater. Here is a pretty useful blog documenting the process: https://aoshunspearfishing.com/blogs/news/speargun-building-101-making-blanks

In my particular case, my current plan is to have a total thickness of 2.75”, using 3 plies of teak. 2.75/3= 0.916. With that said, it seems like a wise idea to have a blank that is thicker than just 2.75”, so if it warps at all during the epoxy-cure hanging phase, or otherwise needs to be redimensioned at all, I’ve got room to spare. Looking at close fractions, 15/16 =0.9375, meaning that if I were to make a laminate out of 3 boards each 15/16” thick, I’d end up with an end laminate thickness of 2.8125”, which leaves me with 1/16” of reserve on the final blank, which should be enough to account for any re-milling that needs to occur if the blank goes off perfectly straight during its curing process. 

Interestingly, the outstanding challenge has been sourcing high quality teak. For those who don’t know: in the past teak has typically been sourced from Burma, or by it’s modern name, Myanmar. Due to some political conflicts maybe a decade or more back, the US stopped allowing the import of Myanmar goods, including Burmese teak lumber. As a result, the US market has resorted to sourcing teak from other countries. This is typically referred to as plantation teak, because these other countries are planting it in massive quantities with the sole goal of producing lumber, and are subsequently cutting down these trees the minute they are big enough for their lumber goals. The unfortunate byproduct is that these young growth trees have nowhere near as good properties as the older growth stuff. I’ve seen it with my own eyes- the grain density isn’t even half what an old growth piece would have. This higher porosity, paired with lower natural oils in the younger wood, makes it less dense, more likely to warp in boating/marine applications, largely defeats the point of using teak.

As for where that leaves me, in trying to source higher quality teak- I either have to track down pieces that have been sitting unused since before the ban, or look through lumber yards hoping to find the occasional piece that has higher grain density than the rest of the new-growth stock. This also significantly cuts down on what dimensions I am able to find the higher quality stuff in. For instance, I went to a pretty well-stocked lumber yard in the Bronx (NYC), they had quite a fair bit of teak, but a ton of it was new growth stuff, and the old growth boards I was able to find were either 0.75-1” or 1.5-2+”, nothing in the 5/4” category. If I’m seeking a milled thickness of 15/16, and I don’t have a bandsaw for resawing, that means those boards would be either not thick enough, or too thick such that I’m either trying to resaw it on a table saw or just running it on a planer a bunch, either way, wasting a lot of money buying unnecessarily thick material to start.

Then, I stumbled upon a guy on facebook marketplace, much closer to me than that lumberyard was, selling some teak boards. In the photos where he’s holding a measuring tape against them, they are clearly 1-1/16” thick. Also, while I have yet to inspect them in person, the photos he’s sent me indicate that the grain density isn’t as awfully sparse as some of the boards I’ve seen in other places, such as that Bronx lumber yard. Seems like these were either a lucky batch post-Burma ban, or maybe he’s had them sitting around since before then, not sure. Assuming they look as good in person, I could see myself buying them for my first speargun build.

The question becomes then, is it likely that I’ll be able to take 1-1/16” boards and mill them to square at 15/16”?

I know a big part of milling also comes down to board length. This guy is selling boards in 6’,7’, and 11’. I am going to be making hybrid spearguns, so instead of a 48” long speargun needing a 48” long piece of teak, it would have, say, a 24” long piece of teak, a 24” long carbon fiber tube that is inserted 6” into the back teak stock, and a 10” teak muzzle that is inserted 4” into the carbon fiber tube (24+24+10 total, -6-4 accounting for overlaps, so 48” total). Hence, my point being, the blanks wouldn’t have to be as long as the end length of the design. But with that said, it would certainly be easier if I could laminate one long blank, take it over to the miter saw, and cut out multiple small parts, as opposed to needing separate glueups for each component. But, I believe that a bowed 6’ board would lose less thickness correcting than a bowed 11’ board would. So if I had to resort to cutting to length pre-milling for the sake of preserving thickness, that would be an option too.

With all this out of the way: do you all think it would be possible for me to start with a 1-1/16” board and get it milled up at or before the thickness is reduced to 15/16”?

As another possible solution to your drilling conundrum, since you are thinking of breadboarding, you could use a core box bit on the router table to accurately route half diameter channels that would line up when glued.
If you go slightly under sized (smaller diameter), it would make for an excellent pilot where using your final diameter bit  can ream to the exact size and be straight. 

@splintergroup I’ve never heard laminating refereed to as breadboarding before, haha. With that said, my father suggested effectively the same thing. It’s not a bad idea, but there are a variety of cutting operations that, according to my current plans, would come between laminating the blank and cutting the deep hole, and if any of those force me to rethink geometries or shave a little here or there, I don’t want to then have my tube off the necessary positions. Moreover, since my impression is that a forstner bit relies heavily on it’s central point- hence why using a forstner bit to upsize an existing hole is difficult- removing the central material would be strolling it of it’s guide as it digs deeper into the wood, no? And since I’m looking at using an odd number of boards for my layup, not sure how what you’re suggesting would be feasible. Still, very clever. I’m not closed off entirely to the idea, just doesn’t fit well within my current intended specifics. 

For the final drilling/reaming I was thinking of a standard (pointed) drill bit. Yes, a Forstner bit would not be happy 😞
What diameter are you aiming for?

Thinking a bit more, if you can get a straight hole drilled with reasonable accuracy, start point to end point, and have your material a bit thicker/wider (1/8"?), you could then use a drum sander or planer with one end wedged up so the top surface is exactly parallel with the hole. Repeat for the adjacent side. The wedging could be a simple wedge or you could insert a steel rod with a slip fit and have the end protrude a bit to place over a raised support on one end.
You would need to be sure the wood was fully supported so it didn't bow down from the cutting so maybe a thick chunk-o-something underneath and the wedge support under that.

Think of it as a tilting table.

Once two 90 degree surfaces are parallel to the hole, you can just lay it flat to surface the opposing sides to the correct offsets.

Look at "lunch box planer sleds" for a better description.

@splintergroup are you suggesting this as a way of reducing the importance of the hole being initially straight to the board?

It’s a clever idea, but not sure why I’d bother with that as opposed to just trying to get it right the first go around. The other thing- this first speargun is gonna be for me, but provided my design works well in practice- I’d be open to selling them as a side project. From a buyer’s perspective, seeing that the laminates do not run perfectly straight to the gun, i feel like that would look incredibly sloppy? And there are other geometries in the gun that would really highlight that error in the end product.

I like your thinking, I have with all the solutions you’ve suggested haha, its just always half a beat off where I’m hoping to be haha. Who knows, it’s still a super useful backup measure to keep in mind.

With that said… all the lathe stuff had been in the comments of my drill press table post. I’m hoping you can offer your thoughts a bit more in regards to the thickness milling question I raised in this specific entry?

Yeah, just tossing stuff out, that's what we do here 🤠

My bad on commenting in the wrong thread, had no idea!

Certainly getting it perfect with the drilling is best, I'm just thinking that planing afterwards to the hole could correct for any errors. After doing that, there should be no issues win laminations running crooked since they are square to the hole .

Anyhoo, to your question here, if the S4S wood is warped, you'll need to lay a straight edge across the boards concave surface and measure the depth at the deepest point. Multiply by 2 to get the minimal wood thickness needed to remove (plane the convex surface flat, flip, then flatten the concave side).
If twisted, lay it on a flat bench, hold down one corner so it isn't rocking, then measure the place with the biggest gap above the table. This will be 1/2 the amount needed to remove.

Which lumber yard did you go to in the Bronx?

@Corelz125 Rosenzweig Lumber.  Was extremely impressed with their overall selection despite being slightly disappointed in their teak. Also, not 100% sure since I didn’t confirm it with the manager or anything, but I asked a few questions of an employee and I was a little bit disappointed in some of their policies given how they impacted my search for teak. A lot of boards, maybe like 25-50% of them, had waxy paint on the ends, preventing you from making out the end grain. Since I’m trying to make sure I get good boards with ideal grain density and direction, the wax covered ends prevented me from choosing those boards. According to the employee, if i were to even just scrape some of the wax off to see the grain, it’d be a “you break it you buy it” situation. Came across as VERY far fetched, but didn’t care to argue as a first time customer there.

With that said, being there gave me a first hand appreciation for the difference between old growth and new growth teak. Just take a look at the difference in this grain structure!

The rings on the board in the less zoomed in photo are easily over twice as dense as the other board.

Why’d you ask? Do you shop there or something?

@SplinterGroup absolutely no worries. 

You’ve got me curious now though- I don’t fully understand what you had in mind. You mentioned using a steel rod or something as a jig to then keep the planer/jointer passes aligned with the drilled hole. Can you draw it out? I don’t follow based on just what you wrote.

Yea thats one of the lumberyards I will use.  Half the time not many people are around on the upper floors so If the teak is up there you would be able to scrape the wax off and they wouldnt know the difference. 

The rod just gives you an option for raising up one end of the wood. You could place a wedge under the wood or arrange a way to raise up the bar and hold it.
Thinking on it, just make a sled with two boards, hinged at the end. The wedge can then go between the boards while the wood sits flush on the upper board (lower hinge pin end goes into the planer first).

Crude drawing with exaggerated hole at an angle:

The bottom board rides on the planer or drum sander bed

@splintergroup reminds me of the hinge solution used in most “drum sander jig for lathe” solutions posted on YouTube.

The thing I’m still unclear on though- how will I go about determining the necessary angles to then have alignment? How will I measure off the cut hole?

You should be able to use calipers to measure the offsets and some trig to know how much of a lift the end requires.
If the hole is a larger diameter (maybe 1/2"+) you can use the calipers directly as the radius of the hole might only add a few 0.001" or so with the flat on the caliper jaw not seating fully. If small, you can insert a rod of equal diameter and read directly from the rod to the edge of the wood.

@SplinterGroup, Unfortunately, still not sure I’m following.

One of the things that’s been driving all my decisions for this project has been a question of ideal vs reality. I’ve already had a detailed, almost entirely complete set of CAD plans for this intended build for months now. The issue has been though, Figuring out how to measure weird geometries, pull off weird cuts, that sort of thing, is a lot easier to do in a computer operation, than it is to do IRL. One of my early takeaways was to go back, and redesign the entire CAD model, only this time doing so with the steps in an order-of-operation that could prove possible outside of just this software’s ’fantasy world’ so to speak. Even now, most if not all of the outstanding unknowns in the project are all based in ‘does it make sense to actually do step 16 before step 13’ or ‘yeah, step 8 looks great on paper, but how could I ever do that cut with that level of accuracy in practice?’ Time and time again, I’ve had to adjust my logic on this project after discovering that it’d be impractical to accomplish it with my previously chosen order-of-operations.

Here, from a hypothetical standpoint, it seems like what you’re proposing sounds great. But I’m not following how in practice I’d be able to come to a confident verdict based off a caliper jaw not seating flush?

If you wouldn’t mind, I’m going to request you draw out an idiot-proof diagram of what you mean with how the measuring with the calipers would work IRL.

Well, for measuring the offset, hopefully these pictures will help:

Since a calipers jaws are not a knife edge, measuring from an edge to a hole will always be slightly greater than reality.
The smaller the hole diameter, the greater the error.

This is a board to represent what I assume you'll see in the end grain of your part.

Measuring to the inside edge of the (1/2") hole directly:

Note, 2.540"
Also need to have the calipers perpendicular to the edge (minimum distance).

Here is the same board on my router table circle jig. The post is 1/2" and this board was actually used on this jig so it's a "perfect" fit.

This uses the dept feature of the calipers and the largish square shoulder on the calipers makes squaring up easier.
Note, 2.538".
A 0.002" difference.
The last measurement is the one I'd consider accurate, but requires the fitted post in the hole.
The first method is quick, just measure and done. 
If I was going to need to get that hole exactly 2.5" away from the edge, I know that I'll need to trim the edge back 0.040". If "close enough" was what I was after, I'd just use the first measurement, lop off 0.038" (or now knowing the error, 0.040") and done.
So with this measurement complete on each end of you stock, measured to the same side, I now know that the greater number - the smaller number gives me the amount of material to be removed.
With this known, I can then place the wood on the hinged sled with the planer set to just kiss the wood. Shims of the calculated dimension can then be used to lift the "fat" end up. The planer will then cut parallel to the hole.
The part then can be flipped 180 and run through the planer until the distance of the hole matches. Since it is already parallel, that part is easy.
Repeat the process from the adjacent side (90 degrees off) and you'll have a square part with a centered and straight hole.
The pieces ends can now be cut square to lenght.

Ok so this would address if the hole was out of position, but are you saying this also makes it possible to measure how “tilted” the hole is relative to the overall wood?