Norris #61

[D_W]

Is that shrinkage after drying or in the drying process? I had thought it quite stable and have used it in knife handles a bit. Cocobolo is generally unobtainable here although it is fantastic stuff. I got a bit for knife scales from the US some years ago. I'll see if I can get Rosewood. Again, fairly difficult to find here. The last lot for a guitar was from Oz but there has been difficulty importing due to the protected nature of many of these woods.

Yes on the import, someone has to import it and take care of the cites paperwork. If they do, it can be very reasonable ($40 for quartered 8x8x3).

Bubinga and purpleheart will continue to expand and contract for a while. If you make a plane in the dry season, the pins and tails may telegraph their lines due to wood expansion. Btdt. Less movement means less telegraphing, but everything moves a little unless you can find really old wood.

 

[D_W]

David, I have enough trouble with dust in my shed without creating mini dust-storms!! Even the toughest of woods yields to a saw, rasps & files which are pretty hard to beat for efficiency when it comes to shaping plane totes & buns imo. Still dusty work with bone-hard woods, for sure, but at least the dust is more limited to the immediate work area & not dispersed over the entire shed. (My dust-collection system has been waiting to be set up 'properly' for 15 years).

Shaping the woodwork for an infill is far less taxing & more satisfying to me than most of the metalwork. The trickiest part is cutting the rebates to fit over the tops of the sides when overstuffing, and there are no powered tools that I could use safely to do that. I find filing off the peened dovetails on a medium to large plane a bit too 'contemplative', & not a very rewarding activity so I do sometimes wish I had a decent belt sander to alleviate that bit of drudgery. But wherever possible, I much prefer a quiet approach that doesn't obliterate the background music. Ain't got no deadlines, these days.

Ian

I've never fitted infills with anything other than hand tools. Working to invisible lines isn't difficult but there are some tricks that make non-show parts easier.

That said, the rough sizing would be easy to do with belt grinder. I leave an open path to the door and run a box fan (mostly grinding metal, to keep the flow of dust and smoke headed out). Leaf blower at the end solves any setting dust and out it goes. But this does require a large opening to push everything out. The portaband and belt grinder are a poor man's fabrication setup. Everything else is finish work that can be done by hand.

 

[IWW]

... Bubinga and purpleheart will continue to expand and contract for a while. If you make a plane in the dry season, the pins and tails may telegraph their lines due to wood expansion. Btdt. Less movement means less telegraphing, but everything moves a little unless you can find really old wood.....

Every wood remains hygroscopic and will move no matter how "old" it is. "Stable" woods are simply those that move least within the typical annual relative humidity ranges they are exposed to. This doesn't equate to initial shrinkage values, one of the more stable woods I use has very high shrinkage from green, but once it finally equilibrates, it is extremely 'stable'. Denser (& especially oily) woods absorb & release moisture very slowly, which makes them a pest to "dry" but once equilibrated, this slow response to humidity changes is what makes them 'stable'. However, they will never stop absorbing/discharging some water vapour in response to RH changes & must & do move a little.

The dovetails on a reasonably well-constructed body should tolerate the small amount of annual movement involved with a 'stable' wood without any external signs, the wood at their level is the most 'protected'. I've not yet seen any indication of the dovetails being stressed on any of my planes, but I have noticed a couple of the rivets through the upper part of the woodwork showing some faint feathering at their edges, indicating there's been a bit of expansion & contraction of the wood.

From my own experience, the most likely scenario with very dense woods is that you'll use them before they fully settle to EMC and end up with shrinkage after a year or two. I've had to replace one front bun when the wood shrank after installation (I think I mixed up some pieces due to poor labelling). It was only a small crack either side, but it thoroughly ruined the look of my plane! So far that's the worst that's happened, all of my other infills have remained tight & the only evidence of wood movement is the slight feathering of a couple of rivet heads as mentioned. The old makers & some new makers use an internal metal sleeve around the rivets. I've never understood the point of these, tbh, the wood can still shrink & open up cracks, and the sleeve doesn't resist expansion. I think teh best I can do is to make sure the wood has had more than enough time to settle & bed the infill with epoxy, in the hope it will slow down moisture ingress & egress a little.
Cheers,

 

[D_W]

Older wood moves less. There is a springback factor with wood. It springs back only a fraction of its expansion, and subsequent cycles equate to overall shrinkage over time. Eventually, expansion in humidity is less and less, but not zero, and moving from a more humid climate to less with old wood can still lead to cracking.

 

[D_W]

Good information about wood stability with seasonal aging is hard to find, probably because it doesn't have much commercial value.

The best I could find was a discussion on internet forums with professional violin and viola makers. Somewhere around 5-7 year old wood is where the makers stop seeing seasonal movement problems. Old wood is a selling point with buyers as far as tonality goes, but I've never seen the difference in guitars from good makers. The discussion with violin makers confirms the same, that tonality is usually adjusted by fine makers and physical characteristics of the wood are more important than age. But for stability, some cycling of expansion and contracting is needed to lower movement and reaction to moisture changes.

Is it absolutely necessary for planes? No. Is it nice to get wood with lower volumetric movement and that is a few years old? Yes. Some limitation of change can be had by allowing at least a season of wood movement in the same place where the plane will be used.

If the infills that I've made, movement is lowest in wood that I've had on hand for a while. I had made a skew shooter out of new kiln dried purpleheart and the springback in the summer was far more than desired, making for telegraphing that can be seen and felt on the tails.

The first large infill that I made 11 years ago with an extremely old blank of bios de rose shows no telegraphing kept in the same area. No gaps or noticable movement at all, but it's not practical to try to find wood like that, either. It's more practical if one is going to do this for the long term to find good blanks at a low price and store them.