Reaming wood?

[hotponyshoes]

I'm looking to fit a bit of round metal bar into a piece of hardwood (counterweight for a knife handle)

If i used a piece of ground round bar could I drill the hole in the wood, finishing it off with a regular metal working parallel reamer to the correct size?


I'm wondering if putting the bar in the freezer and tapping it in would hold it in?
Or just tap it in with some adhesive?
Or make the hole oversize and fill with some pigmented adhesive?

Although my main question is how to get a accurate smooth hole in wood in the first place!

 

[eLuSiVeMiTe]

Wouldn't bother. Drill it just about right and epoxy the metal in place
End result will be the same with a lot less effort

 

[mtt.tr]

As above, if you want it tight but silly tight regrind a spade bit to desired size

 

[TechnicAl]

Wouldnt the wood split

 

[mike os]

tight and round are both bad

If its just a weight then you don't need the accuracy and its better to be epoxied in anyway

 

[gaz1]

before you epoxy also check its balance too heavy on handle and it will drop handle first

most blades drop blade first

 

[Parm]

Didn’t the Vark mention something about melting soulful to fix a handle ?
Think modern epoxies are a much safer alternative

 

[hotponyshoes]

I might just spade drill oversize it then fill with some pigmented epoxy.
I wanted a good fit as I am planning to leave the back side of the handle flush with the wood so it will be visable when finished

 

[hotponyshoes]

Didn’t the Vark mention something about melting soulful to fix a handle ?
Think modern epoxies are a much safer alternative

Is that predictive text or some sort of product?

 

[Parm]

Is that predictive text or some sort of product?

Bloody stupid keyboard on the iPad, should have read sulphur

 

[Agroshield]

Easy way is to use the ground bar itself as a toolmaker's reamer. See top of:

https://www.homemodelenginemachinist.com/attachments/reamers-gif.32194/

 

[bigegg]

I'm looking to fit a bit of round metal bar into a piece of hardwood (counterweight for a knife handle)

If i used a piece of ground round bar could I drill the hole in the wood, finishing it off with a regular metal working parallel reamer to the correct size?


I'm wondering if putting the bar in the freezer and tapping it in would hold it in?
Or just tap it in with some adhesive?
Or make the hole oversize and fill with some pigmented adhesive?

Although my main question is how to get a accurate smooth hole in wood in the first place!

You cant get "accurate" in wood - it changes size and shape with temperature + humidity.

 

[The_Yellow_Ardvark]

You don't whant the metal to be tight in the hole.
Wood moves and a tight fit will cause issues.

As @Parm said, sulphur can be used. But a good 2 pack glue will do just as good.
Or if you want to go the whole hog.
Hot animal glue mixed with sawdust from the wood you are using.

 

[Seadog]

You cant get "accurate" in wood - it changes size and shape with temperature + humidity.

But you can get close, surely? Boxwood, Ebony, to name two (I can't think of any more this early on )

 

[bigegg]

But you can get close, surely? Boxwood, Ebony, to name two (I can't think of any more this early on )

For a given definition of "accurate", yes.
But even then - never to the point that reaming is neccesary.

 

[Seadog]

Ah, the coffee kicked in - Lignum Vitae

 

[hotponyshoes]

I have had a go with a few bits and it sort of works.
I am using iroko for the tests.
The only bit of round ground stainless I have that matches a reamer i have is 12mm
I am drilling into the end grain.

First hole was done with a 12mm drill bit just to see what would happen. After a bit of trial & error I have managed to get a hole that the bar only needs a light push to fit but it's out of round.
Possible that the wood could be clamped firmer on the mill etc. but probably more hassle than it's worth

I tried the 12mm reamer, first drilled out to 11.8mm than ran the reamer in by hand. Reamer just pulled the grain in and splintered it.
Bit more messing and a 11.5mm drill, then countersink, then reamer at high speed in the drill did a very good job.
There is obviously a little spring-back in the wood (or the reamer/bar are not exactly the same sizes) as it's a rubber mallet job to fit the bar.

It could then be carefully sanded on the end to get a decent gapless finish. I would be concerned that any expansion of the wood and the bar could just drop out although the blade will be fixed with a through-bolt so I could add another for the bar. Or if the wood contracts/bar expands its probably enough to split the handle along the grain.
Probably other forms of wood that are stronger, one of the engineered types like pakka may be a better choice for something like this.

Anyway, I have stopped messing with this now as I cut off a test piece of 25mm and it's not heavy enough. I wanted to use 22mm or so on the real thing.
I'm now thinking of either a bigger bit of bar that I turn part down to glue inside a hole so the rear part of the handle is stainless or I hollow out the rear and fill it with something heavier?
Maybe a lead plug? I have got various heavy metals, osmium, tungstan, tantlum, etc but they are all in ball form so I don't know if they will actually be any heavier as a lot of the hole will be filled with gaps.
If the balls did weigh up a decent amount heavier i could put them in then fill with epoxy but then i still need to make some sort of end cap for it anyway.
I might rough profile a bit of 35mm bar later and see how that weighs up...

 

[slim_boy_fat]

Surely the grain structure would have a part to play in how accurate any drilling would be?

 

[hotponyshoes]

I think so. A denser wood is going to go a lot better than a less dense one.
Once I had the pilot hole the right size a sharp reamer just cut into it nicely and left a very smooth finish.
I may have had decent results with a wood drill bit but I only have metal ones.
I was also drilling on a pillar drill, could have made the thing better by putting it in the lathe or mill I expect.

It seems like a lot of knife handle wood is a epoxy laminate formed under very high pressure or even wood powder mixed with epoxy. Those types may be fine but only seem to be easily available as scales rather than a block.

I was planning to use a one-piece handle and fit the existing tang of the rasp stock I am using into it.
After forging the first blank down i do actually have enough metal that i could make another and fit a scaled handle. But I spent several hours forging the first one...

I might do another mock-up with a full stainless handle but I don't think that's really going to get the weight at the back where i want it.

 

[bigegg]

It seems like a lot of knife handle wood is a epoxy laminate formed under very high pressure or even wood powder mixed with epoxy. Those types may be fine but only seem to be easily available as scales rather than a block.

It's not difficult to cast a block.
Make a mould from a piece of 3x2 as a base + ends 6x1 (or 18mm ply) as sides.

Make up a batch of slow cure resin.
Dip strips of fibre glass or card, or cloth, or felt (or all four!) into the resin, then lay in the mould.
When it gets to about 3-4" thick, lay another piece of 3x2 on top, and tighten down with clamps/weights.

You'll need to wax/oil the mould to stop it sticking.
I use cheap margarine from asda.

If you want a *really* slow cure resin, use cascamite glue - takes about 24-48 hrs to cure

Felt + cascamite knife scale experiment: