Bamboo Tips - Tips Area
Splitting - Post Heat Treating

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I think cane splits better after heat treating.  Here is my method, worked out by trial and error (mostly error):

Don't try cutting too close to the nodes; even if the cane looks fine it will have some crooked "grain" near the node and when you split the strips they will have a little dog-leg bend at the end.  Plan on loosing an inch on each side of the node.

I split each intranodal section in two before heat treating, and mark the inside using an art marker with a fine nib at one end and a wide nib at the other.  The section at the small end of the culm gets 1 thin stripe, next section gets 2, etc.  The wide mark is a 5.  Etc. Try to heat treat all the sections, even if it is more than you think you will need, lengthwise. You might need it.

I've got a coffee can full of nails & screws for ballast, with a bungee cord knotted around it.  I slip the half section under the cord to hold it vertical, and mark around the top using a flexible plastic ruler and a pencil.  I use 1/4 inch for the tips and a little more for the butt strips.  You can probably go finer, but cane is cheap.  On the other hand, if you make your strips too wide your splices will get longer and you will loose length.  Geometry is a cruel master.

I split with a junk wood chisel ground on both sides and a mallet.  Make your first whack at each split solid, not a little "tap" which will make the chisel bounce off the mark.  One whack then a twist of the chisel and the strip is split.

I've not tried the sanding disk method, but it sounded interesting.  I cut the bevel on a bandsaw with a fine tooth blade and a little sliding jig, then a few passes with a plane in the splicing block will smooth the cut ready for gluing.  A grooved plane sole will preserve your splicing block.  If you haven't got a grooved plane that might be a priority.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

Do most guys on this list heat treat partially or fully prior to splitting??  (Al Baldauski)

I've heat treated after node pressing, straightening and rough beveling.  Never really had a problem with splitting after I started using the Nunley method.  It's pretty darn quick too.  (Mark Wendt)

I concur with Mark --  The Nunley method  (which is on Todd's page) is, to me, far superior to the other methods I tried.  The point about splitting in half until one has a piece thin enough to bend is a very good one.  I concur with that also.  (Joe West)

The Nunley method is very similar to Kreider's method on page 49 of his book.  This method, as described by Kreider in 1951, was probably used regularly prior to his book.  Holden describes a similar method, albeit using a knife to go through the nodes, in his book, written before 1920.  (Chris Raine)

A substantial advantage of the approach I described is you are splitting the size (basal width) of the strips you need. If you discover a flaw in a strip later down the road, you can go back to your unused/unsplit sectors, and bring a new strip into your rod from that unused sector (which can involve a substantial area of the culm). You can leave those unused sectors intact/unsplit therefore, and use them as butts or tips, because they can remain undivided until the time for needing them arises -- and a plan for dividing them for their specialized purpose is dedicated to that specific unused sector.

How much of an advantage is that? Well, I often got two rods out of a culm with spare material left over, despite the substantially greater flat width of rectangular sections. I wager that you are going to have considerably more excess material, owing to the crude increments you are going to "halve." One inch splits to a half; half to a quarter; etc. If then you need tip strips for instance with a base width of 0.255, your method would require a half inch strip -- a huge amount of waste (almost only half the strip goes into end product). You also have a tremendously greater amount of waste to plane or mill away -- far greater work. In fact, versus planing or milling only the 0.025 away I described, you may have 5 to 10 times the planing or milling to do -- harder on your cutters, your arms, the number of times you have to resharpen and/or re-set-up. Not to mention how much cane your are converting to waste.

Note also then, that if you refine your process to one of least waste and greatest effect of exercising the halving principle, you will have exactly the division process which I described. It's just a matter of basic math.  (Mike Montagne)

Might anyone have an outline of John Bokstrom's plan for cutting to length, staggering nodes, and splitting?  It's very similar to what Mike has proposed, but perhaps easier to comprehend.  It was in TPF several years back, and I did a presentation on it at SRG about 5 years ago.

Good work Mike.  Basically, one plans for strips .060" over the largest diameter for butts and tips.  Multiply that number by four.  Then divide the circumference of the culm by the product.  With different culms, you will get 5,6,7,8 or possibly even 9 groups of four strips.  (I usually get 7-8 for tips, 6-7 for butts) Wrap a piece of masking tape around the culm, and mark it in 5,6,7,8, or even 9 equal pieces.  Split the appropriate number of pieces.  From that point forward, split in halves, then quarters.

The description above isn't nearly as clear as John's original instructions.  Sorry.  (Harry Boyd)

I don't have John Bokstrom's directions, but I'd like to say that David and I saw Ron Grantham demonstrate that method with John in attendance at Canadian Cane a few years ago.  Then, Saturday I was sitting with John at the Catskills when we looked over and saw that David was demonstrating  John's method to some new rodmakers. It was an amazing moment for me, and a wonderful accidental tribute.  (Kat Scott)

Many rod makers flame their cane before splitting.  Some of that flaming is very light, some almost charcoal.  I know very few who heat treat entire culms or culm halves.  Some of the Texas crew uses cane that Bob Radasch and/or John Bradford heat treat before splitting.

I built a coupla rods using culms that Bob Radasch heat treated before splitting.  I found it very easy to scorch nodes, and very difficult to get the nodes straight and flat using my normal methods.  When one heat treats before splitting, other processes must change as well.  (Harry Boyd)

Note also however, that if you heat treat after other processes, such as planing/milling, you change the size of your strips.  (Mike Montagne)

But if you heat treat after rough beveling, before final planing, what does it matter?  (Mark Wendt)

I think Mike means that the strips will shrink after heat treating. So you need to keep that in consideration.  (Danny Heus)

That was my point.  I'm final planing after heat treating, not before, so it really doesn't make a difference.  (Mark Wendt)

None of course, except that you're splitting green cane, and your heat treat will lack the flattening effect of treating the culm halves as I described.  (Mike Montagne)

What does the flattening effect give me if the way I do it is split, straighten, flatten my nodes, rough bevel, heat treat, then final plane?  Not trying to be sarcastic or anything, just curious.  I would think the flattening would be more advantageous  to quad rods rather than hex rods, right?  (Mark Wendt)

Implicitly, you admit to have a convex surface on the strips you plane.

What processes then do you deploy which ensure the very apex of that convex surface is ultimately centered in the ostensible "flat" of the finished rod, and that the corners of that "flat" end up on a true cord bisected by a radian of that apex; and how do you even measure that at any phase of the operation(s)?

From your previous post I'll assume your answer will simply be that you and your many even different processes have just as good a control over that as any other method, however comprehensively qualified and differentiated for the explicit purposes.

But maybe those whose work is to excel ought to think about that.

If the heat treat process described has the further ramification of opening the culm to a remarkable degree; and if one light pass with a scraper down the center of the strip, and hand sanding as exactly described and purposed renders a flat which will not engender the non-symmetrical defect anyone without the requested process WILL SUFFER, then you won't need such a process, will you? And your flats will be flats; and your section will have the symmetry necessary merely even to rendering a finished instrument which might not kick  out  in who-knows-what direction under flexure -- inclusive of course of any possible [DIFFERENT] direction, at any and every station of the rod.  (Mike Montagne)

Yes, I do end up with a convex surface on the strips I plane, as do you, or anybody else for that matter unless they scrape, plane, or mill the enamel side of the strip flat.  Does your method of heat treating half culms actually flatten the half culm to a bamboo "board?"  If it doesn't do that, you still have a convex surface on the enamel side of the strip.  Granted, the convexity will have a larger radius, but it will still be convex nonetheless.

I scrape a small flat in the middle of the enamel side so it sits in the forms with one 60 degree side against one side of the form, and that small flat against the other side of the form.  I measure the 60 degrees by using a Starrett 60 degree threading gauge.  Is the Starrett gauge not precise and accurate enough to measure 60 degree angles?  If so, that'll certainly upset thousands of machinists who've been using the tool for many years.  Who knows how many threads they've cut that just aren't accurate.

Maybe those whose work is to excel should have an open mind to other processes that are different from their own.

So, how do you control how much of the convex side flattens  out during  your heat treat process?  How do you ensure that you get the same amount of flattening every time on every culm that you heat treat?  Are all your culms physically identical?  Do they all shrink and flatten exactly the same amount every time?  (Mark Wendt)

PLEASE! Splitting the cane is the easiest part of rod making. Like growing matter, with properties similar to wood, they split better green than cooked. Green wood straightens easier and better than cooked wood. The amount of shrinkage is minimal at best. Split it, plane into a triangle, bind together and then heat treat. This isn't rocket science, shingle makers have been splitting for hundreds of years now. Pulling the split down the strips is the best way to control the split. In the 30 years of making rods I have tried all methods and the only two worth two cents are Nunley's method and starting the split and pulling the two pieces apart with your hands.  (Patrick Coffey)

I see there is more than one way to skin a cat. No, I mean split bamboo.

Here is another way that I have not seen mentioned, it is the one I use. Mark off the culm as to the width of the strips you will be using, I use 1/4 " most of the time. To split the culm, start the fro, put the opposite end against some thing solid. I use bottom of one leg of my workbench, and twist the fro from side to side. You can also just use your hands to split the culm in half and then quarters.  Then split half and half unless you want to split so that you will have 1", 2" or 1/2" sections.

I don't bother doing that, I usually end up with 3/4" section. This means splitting in thirds. NO WORRY AT ALL.

When I get to splitting in thirds the trick is to bend the fat side away from the split. Again no worry. Start the split with a froe, move down the split just enough so that the FAT end at the split can be placed against a solid surface, I use the 4X4 post in my shop.

With the section against your side, lean into the section so that you bend the FAT side away from the split. Work the back of the fro from side to side The split will progress straight by increasing or decreasing the pressure against the fat side of the bamboo section. After you do a couple of sections, it becomes automatic. Those that have been seen me do this are amazed on how easy and quick it goes. Nice straight 1/4" strips.  (Tony Spezio)

Enough already.  I have probably used as many methods as can be counted on my fingers and toes. (I do have to remove my shoes.)  I have even seen Mike Shaffer split a perfect 1/8"  6' strip with a pocket knife.  I can't do it and I am not about to try to learn.  I use only the Moon Method, which is a highly guarded secret.  Frankly I think that this is much ado about nothing.  Split the culm any which way.  Who really cares.  (Ralph Moon)

PS: No Offense Tony, but I can' do it your way either.

No sweat Ralph, I can't do or don't want to do it any other way either. I have given them all a try, the way I do it works for me, It may be a pain in the 4X4 for others.

I have to a agree with Mike on one thing, I do flatten the enamel side before the finish planing of the strip. I do it when the strip is close to finished. It is about as narrow as it will get as not to scrape the power fibers down.  (Tony Spezio)