Here's a brain buster, wood handle steam fit??

Brad_bb · January 14, 2011, 11:05:24 AM

I'm trying to figure out how the wooden handles were originally installed on my Millers Falls boring machines so that I can make new ones for installation.

The wooden handle is tightly adhered to the brass sleeve. The brass sleeve is captured and rides on a steel pin. It rotates freely on the steel pin. the big trick, is how is the handle adhered to the brass sleeve? The brass sleeve is inserted about 2/3rds of the way into the wood handle. I have handles of two designs from the different machines i have. The first is completely solid, while the second is bored completely through the long axis, and has plugs inserted in the ends after installation. The plugs are only pressed in and I am able to grab them with two utility knives and remove the plugs. These machines were produced from 1872 thru the mid 1930's. I believe my machines are from the late 1800's based on knowing what featured were changed through production.
I don't think they used any glue, because I suspect they didn't really have an efficient one that could do the job of bonding the brass to the wood back then. So my thought is that somehow it's a shrink fit. I think they drilled a tight fit hole and perhaps softened the fibers or expanded the hole, then inserted the brass/handle arm assembly, and then shrank the wood down onto the brass. I further suspect that the wood handle was either steamed, then quickly installed with a slight press fit and cooled and allowed to shrink, or the wood was turned green, installed with a slight press fit and then kiln dried. I would think the first scenario would be more plausible as you'd be under a time constraint working with green wood and I'm not sure they had a kiln back then. The difference in handles, solid, and with holes, may have been a solid early design, then later having the holes to allow for faster cooling/shrinkage?
I know it's a long shot, but if anyone has any information, or old books that might have this information/technology, I'd appreciate hearing about it. Thanks, Brad

SwampDonkey · January 14, 2011, 11:29:42 AM

Shrinking may have a little something to do with it, but only in drying the wood before drilling. A hole drilled into wood tends to get bigger as wood dries, like the handles on a file or lathe gouge. So they are wedged in or a rivet or steel pin is tapped or pressed on a copper or brass collar on the end of the handle. But I suspect that the end of the brass was beveled so when tapped into the wood it slides easier through the wood then coming off. While trying to pull it off, the edge of the brass will bite into wood. Otherwise the wooden handles would keep coming off. Just my WAG. ;D

Brad_bb · January 14, 2011, 12:58:27 PM

Thanks for the quick response. I show in the pic one of the arms with the brass sleeve and no handle. The brass sleeve appears completely smooth. No evidence of any taper or tangs to bit into the wood. Granted, one option in the end of the day would be to use a knurled sleeve to try to bite into the wood. But the original method seems to have worked quite well if I can just figure out how they did it. I was thinking that steaming would loosen the fibers on the surface of the hole, but not necessarily penetrate the whole handle. Then pressing the pin into the softened hole, as it dries, might get tighter on the sleeve?? I hope I can get some knowledge on this before I have to start experimenting. I wonder if it could just be straight up press fit? Incidentally, the handles seem to be of a very fine, tight grain wood.

Just Me · January 14, 2011, 04:47:31 PM

My guess would be a straight up press fit. One of those handles that you can see the wood looks like rosewood. I would say bore the hole in the wood just a bit tight, freeze the brass insert and use an arbor press to press the new handle on using dishsoap, diluted a bit as a lube, as it will dry up and cause no problem later.

I have a scrap box full of exotics that I could scrounge you up a piece big enough, or you could use osage orange that is plentiful in your area.

Let me know if you need some wood, I think I have a piece of cocabolo about the right size.

Larry

SwampDonkey · January 14, 2011, 04:59:55 PM

It would have to be cooked an hour an inch to penetrate the whole handle. Steaming would cause swelling. Then drying would make it loose on the copper sleeve. Drying is going to occur from surfaces toward the centre of the wood, surfaces including a hole. In the two knobs there, is does appear that they drove the copper sleeve in the radial grain direction which would reduce the shrinkage in about half. I think the handles were dried below EMC, like down to 8-10 %, then drilled and the moisture gain from the air made the handles grip the brass sleeve from swelling. Steaming could reduce the swelling time. ;) I would drill them so they are going to just pass over them sleeves.

Brad_bb · January 14, 2011, 05:34:37 PM

Well several people now seem to think that steam isn't such a good idea. It looks like I'm going to have to try a straight up press.
-If I wanted to dry them lower than ambient moisture, how would I do that? Did they have that ability back in 1880?
-How wood type dependent is this? Would a maple handle stand up to being pressed?
-My last resort might be a knurled sleeve with some glue on it to bite into the wood and fill the spaces with glue.

When I was talking about steam, I was thinking of only enough to soften the inside surface of the press hole, not trying to soften the whole handle all the way through. I'm not trying to bend wood, just soften the surface. I thought that it would allow some of the wood surface to compress and hopefully hold tight, especially if a knurled pin were used. The fibers could expand back into the knurls. Who knows, but I'll try the straight up press first.

Thanks for the offer of the wood. I'm probably not going to use a native hardwood like maple, walnut, and ??
I'll have to make up some rectangular blocks I can drill and try the press on. I may rough up the brass surface slightly with a scotchbrite pad before pressing.

Dan_Shade · January 14, 2011, 05:50:41 PM

hang them close to a wood stove, the high heat near the stove will drive out the moisture.

you could also put it in the oven, or maybe even the microwave.

Why not just glue it with epoxy? (we won't tell anybody

)

SwampDonkey · January 14, 2011, 05:50:59 PM

Quote from: Brad_bb on January 14, 2011, 05:34:37 PM
-If I wanted to dry them lower than ambient moisture, how would I do that? Did they have that ability back in 1880?

Yup, set the handles on a drying shelf beside a hot stove for a few days. They never had a moisture meter but could measure if moisture was being lost by weighing. Or they could have had a recipe to let the wood dry for so many days/hours.

By steaming I thought you were not bending wood, but making it swell. For what your thinking of, just drop them in a water bucket for bit. Your thinking of raising the grain I guess. ;)
When drying after the steaming, the wood would not expand, but contract.

Ditto Dan.

You know Brad, just because the Wood Products Labs around the world created testing standards and wrote books on ID of wood, don't mean those old timers didn't know about wood properties pertaining to moisture. ;) Some stuff they couldn't see, but they knew what was going on. Just not the minute things.

SPIKER · January 14, 2011, 08:13:07 PM

I remember seeing soemthing done back in the day on a black & white very old film that had them using expanding wedges (think muffler pipe expander) to expand bushing inside of some wood wheel blanks then reamed them to size internally. Not sure what the wheel/pulley was for but it was a very heavy hunk of wood that had steel bands around outside of them. they froze the brass bushings then pressed them into the wood with a large arbor press then dropped in a series of feather wedges and hit them with the arbor press again. It appeared they smeared something around the brass/wood hole prior to pressing not sure if it was water glue or oil.

Otherwise I agree with others snug fit hole and some epoxy. ;)

Mark

metalspinner · January 14, 2011, 08:58:28 PM

I like Just Me's idea, but that's just me.

If the wood is not at equalibrium and high in moisture, it may shrink around the brass and hold it just fine.

SwampDonkey · January 14, 2011, 09:41:47 PM

The hole will get bigger I'm afraid. ;)

Bodger · January 15, 2011, 01:26:05 PM

most ladder back chairs you see are built on the fact that a hole drilled in green wood shrinks when the wood is dried. Green legs (posts) and bone dry rungs are put together and will hold much longer than a glue joint when the leg shrinks to hold the post in place.

SwampDonkey · January 15, 2011, 01:45:58 PM

That must be why I'm always gluing chairs back together because the holes are shrinking tight. :D :D

SwampDonkey · January 15, 2011, 02:59:48 PM

A little experiment:

Exhibit 1:

A cherry dowel turned to 3/4" with matching hole in flat piece of cherry. Been drying for days beside a hot stove. No idea of moisture content, but can assume dryer than air in the house. Let's guess around 10 %.

Snug/tight fit same MC% whatever it is.

Submerged in water for a few days with another pair of wood pieces called exhibit #2, a flat piece of cherry we will call exhibit #3, and cherry dowel wood is also in the water bucket to be labeled exhibit #4.

Exhibit # 2 is wet wood before turning a dowel and drilling matching hole. Unknown MC. The two pieces were soaked 168 hours first.

Exhibit #3 has a wet square piece for drilling a hole, but a dry dowel that were cut at the same time. Unknown MC's. The wet square piece was soaked 168 hours.

Exhibit #4 has a wet dowel and a dry hole drilled in the square piece at the same time. Unknown MC's. The wet dowel was soaked for 168 hours.

Exhibit #1 was removed and is left to air dry in the house for a few days/weeks to see if they can be pulled apart. Exhibits #2, #3 and #4 are brought to the house for a few days/weeks of air drying as well to see what happens. ;D

metalspinner · January 15, 2011, 03:07:45 PM

SD,
You're making my head hurt. :D

My guess is that any of the holes you have drilled or will drill will come out oval after they reach equilibrium.

SwampDonkey · January 15, 2011, 03:10:12 PM

I want to look at it all four ways with pieces being dry and wet. ;D The first one we are calling dry, but I dropped them in water to speed up moisture intake and then will let them adjust to the the house air for EMC.

SwampDonkey · January 15, 2011, 03:14:56 PM

Quote from: metalspinner on January 15, 2011, 03:07:45 PM
My guess is that any of the holes you have drilled or will drill will come out oval after they reach equilibrium.

Yes, because of radial vs tangential movement. Works the same either way, drying or wetting. ;)

Brad_bb · January 16, 2011, 02:27:31 AM

A good experiment, but just a note that I don't think it addressed my original issue. I have a brass sleeve that will be pressed into a wood hole. I realize that you are probably just doing your own experiment. I suspect that the wood dowel will shrink, and the hole will not shrink as much, and you'll end up loose. Also, are you starting with a slip fit, or a press fit?

SwampDonkey · January 16, 2011, 06:12:13 AM

Your are right, that it isn't exactly the same situation since both pieces are wood and you have a brass sleeve against wood. The fit is a slip fit, but a tight slip fit, wood is compressed slightly. As to the experiment, it is done 4 ways, so not all pieces will shrink when we start with dry pieces below EMC. We'll see. ;D They are all same species and cut from the same 2 pieces of wood. It's just a lot easier to use wood since I have no sleeves of any type metal. Being the same species the drying and wetting will be the same proportions (T/R) in either of the pieces. The parts that are both dried below EMC should swell and stay tight. I've got them in water just to speed up wetting. They will be pulled out of the water and allowed to adjust to the room air for several days. I don't think much compression will happen over night to the fibres, so they won't be crushed hopefully and become loose. Water doesn't move that fast into wood unless steamed. ;)

We also have a gentlemen with a chair construction scenario. I can't imagine a wood hole shrinking smaller when it dries. Going to dry from the surface (including hole surfaces) toward the centre of the wood, not the hole. ;)

jim king · January 16, 2011, 09:10:59 AM

I have seen hot file tangs and turning tools inserted into a drilled out undersized hole in a wood handle and in the hole is a tree sap called brea, it looks almost like tar. You have to break the handle to get it off and scrape off the wood splinters attached to the metal.

Brea is also put under tin can patches tacked to wooden dugout canoes for a water tight seal. Maybe a tree sap up there has the same properties. Brea comes in peices like coal and has to be melted in a tin can to use.

?¿?¿ ???

SwampDonkey · January 16, 2011, 09:47:48 AM

Some type of bonding agent that adheres to wood and metal will achieve the same thing Jim.

jim king · January 16, 2011, 09:53:32 AM

SwampDonkey :

I was thinking that old technology like tree sap may have been how the originals were made.

SwampDonkey · January 16, 2011, 10:06:46 AM

Yeah, possibly so. The Indians used spruce pitch on canoes up here. People often assume that before some of these institutions of research were set up and funded by government that folks 4 or 5 or 6 generations before had no understanding of what's going on. Especially so for wood, since we have folks wanting to buy old furniture and pay $100,000's for it. Well, you wouldn't pay that if it was falling apart like junk. ;)

Just Me · January 16, 2011, 10:12:07 AM

For what its worth when I set new chisel handles I use a few drops of West System on the tang. It may be cheating, but I use my tools, and have no doubt that if it had been available in the old days, the old timers would have used it as well. My only concern is that the tool works to help me make a living, I have a woodshop, not a museum.

The West System not only fills any small voids, but seals the inside of the handle so it will be resistant to seasonal changes.

Brad_bb · January 16, 2011, 04:17:55 PM

The more we talk about it, the more I think a press fit and a light coat of epoxy on the inside of the hole may be the way to try. I must embarrassingly admit that I don't yet have a drill press, only regular hand drills. I need to get one so that I can use a machinist vice etc to clamp such handles while drilling.
What would be the best to use to make the holes. Regular drill bit, Brad point, spade bit? I'm thinking regular because I can get any size imaginable, whereas the other may only come in common sizes.