Cutting pith wood

[HectorLooi]

Just how do you cut pith wood?

When I see commercial pith wood buttons, I marvel at how smooth the cut surface is. When I cut pith wood, I always end up with a jagged, ragged, crooked cut. Regardless of using a saw, serrated knife, kitchen knife or razor.

[Neverenoughwatches]

2 hours ago, HectorLooi said:

Just how do you cut pith wood?

When I see commercial pith wood buttons, I marvel at how smooth the cut surface is. When I cut pith wood, I always end up with a jagged, ragged, crooked cut. Regardless of using a saw, serrated knife, kitchen knife or razor.

I use pithwood from the elderberry tree in my garden. Cut off branches around 50mm in length then force out the center pith with a same size diameter piece of timber. The pith shoots out of the cut branch with a pleasing "plop" sound . Oh yeah the cutting , a new razor blade with a slight sawing action, a lot depends on the density of the pithwood, some light stuff takes a little more gentleness.  I doubt you wont find anything much thinner than a razor blade you could possibly increase its sharpness with a very fine stone and then hone the edge afterwards on a strop. Sharpening and honing are two different processes. Why ?  i ask for your question Hector.

[HectorLooi]

@VWatchie mentioned recently that he wets a piece of pith wood with degreaser and pushes the pinions into it to clean them.

So, I dug out my pith wood and tried to cut some buttons off them and made a real royal mess.

I try again later with a new razor blade and see if that helps. Or maybe I just have a bad batch of pith wood.

[Neverenoughwatches]

26 minutes ago, HectorLooi said:

@VWatchie mentioned recently that he wets a piece of pith wood with degreaser and pushes the pinions into it to clean them.

So, I dug out my pith wood and tried to cut some buttons off them and made a real royal mess.

I try again later with a new razor blade and see if that helps. Or maybe I just have a bad batch of pith wood.

If its soft stuff, careful and slow slicing action. I like to use soaked pithwood for polishing jewels, wedge shape the end and pop it onto broach to use as a handle.

[nickelsilver]

I'm fairly certain it's cut commercially with a spinning razor sharp blade, like a meat slicer. I've never been able to get such a clean cut with a brand new high end Japanese razor knife.

 

[HectorLooi]

Thank you. I feel vindicated now. 

[Marc]

I cut this using a 100 year old cut throat razor and just slicing through. The holes are where I've been poking an oiler into the end of the stick.

Your razor does have to be shaving sharp though, which is a heck of a lot sharper than most (any) disposable razor blade.

You could also use a microtome blade, which is effectively the same thing but is used to prepare thin tissue sections for microscope slides.

Edited March 17 by Marc
Additional info

[fixermole]

nickelsilver is likely spot on -- pith wood has the consistency similar to polyurethane foam which is cut on an industrial scale using large band saws with smooth, razor-sharp blades spinning at high speed. Those saws even smoothly cut even the most "squishy" foam compositions. (This was one of several dangerous, nasty and/or boring jobs that enforced my decision to continue my education).

[spectre6000]

I do hand tool woodworking (luthiery, furniture, etc.). Requires have an incredibly sharp blade. I forget what grit my finest diamond hone is, but I finish with lapping compound on a steel backed strop. There exists a grade of hone called "surgical". I don't know if it was a medical standard at one point, still is, or if it was just as fine as could be had at some point in time, but I go way past that. Done correctly, you have no need for sand paper or any other abrasives. You get a glass smooth finish right off the blade with no fine dust to worry about.

The trick to cutting pithwood is a really sharp blade, and kinda roll it on the table top. That'll get you one clean side, because the bevel of the blade will slightly crush the other side. Still usable, just not as pretty. Sounds like the commercial guys can get both sides clean, which would be nice. You might be able to get away with a fresh razor blade, and that would probably get you two OK faces.

Edited March 17 by spectre6000

[Neverenoughwatches]

1 hour ago, spectre6000 said:

I do hand tool woodworking (luthiery, furniture, etc.). Requires have an incredibly sharp blade. I forget what grit my finest diamond hone is, but I finish with lapping compound on a steel backed strop. There exists a grade of hone called "surgical". I don't know if it was a medical standard at one point, still is, or if it was just as fine as could be had at some point in time, but I go way past that. Done correctly, you have no need for sand paper or any other abrasives. You get a glass smooth finish right off the blade with no fine dust to worry about.

The trick to cutting pithwood is a really sharp blade, and kinda roll it on the table top. That'll get you one clean side, because the bevel of the blade will slightly crush the other side. Still usable, just not as pretty. Sounds like the commercial guys can get both sides clean, which would be nice. You might be able to get away with a fresh razor blade, and that would probably get you two OK faces.

Agree here with you specs, I'm struggling to understand how its a problem. I use a single sided razor that i use for other things and sharpen that on a 3000 grade sintered ruby stone which is usually enough to get a clean slice. Anything better than that then i go to a 2 1/2 section of Tam o' Shanter that i took from a very old bench stone that i used to use for creating super sharp edges on Jap chisels. But yes a new razor blade out of the box cuts the pith i use just fine ?  Not sure why the clean cut is important if pinions are just pressed in to soak up degreaser ?