replacing shanks.

sawguyver · February 18, 2006, 03:24:20 AM

I would like to change every second shank on my blade to see what the difference is in performance. Like how the sawdust flies.

The reasons for every second shank are :

No.1
I only have 30 new shanks and my blade has 38 teeth and the older shanks are worn.

No.2
I want to try sawing frozen wood (poplar, pine, basswood and maybe maple). My power unit is only putting out about 40 hp. and I'd like to try putting new teeth on only the new shanks.

No.3
I'm just playing with the mill and want to see if cutting with every second tooth will work. It did fine in soft wood this summer but supposedly its underpowerd for hard wood. It would be nice to Know if this could be a solution rather than changing the motor for now.

??? Would I have to have the blade re-tensioned ???

Its fun to make little changes and see what happens but maybe this isn't worth it. :

isassi · February 18, 2006, 03:45:56 AM

I'm no expert, but if you give some thought to what you are wanting to do, you are reducing the blade's ability to cut in half. To my way of thinking, it would be like filing every other tooth dull in a blade. As to the shanks being worn, if they do not hold the bits properly, then they should all be replaced. I would guess if they are bad enough, if you were sawing through a hard spot, the bit could come out and then things would get really interesting. My guess for your power unit and blade, you need all the bits to be sharp and RPM to be optimal due to you are way underpowered. Good luck.

sawhead · February 18, 2006, 06:36:12 AM

Replacing every other shank is not uncommon but its normally a cost issue or a saw tension problem. Let me qualify that saw tension statement , replacing shanks will put tension in a saw, it's quite often that a saw with worn shanks will have symptoms of needing hammering. Worn shanks will also let dust spill out and heat the saw, I have taken a round file and squared the shoulders to overcome this for a short time. I don't beleive that you will overcome the underpower issue by leaving out teeth , that said , with sharp teeth ,good shanks and patience I wouldnt hesitate to cut hardwood . Patience because with a smaller power unit it will just have to be fed slower.

Ron Wenrich · February 18, 2006, 07:13:00 AM

I've always been told that when you change shanks, you should have the saw hammered. I'm with sawhead on the sharpening the shanks issue.

What type of shank do you have in your saw? I run winter shanks and summer bits all year long. If you have summer shanks, you could put in winter bits (standalls). That will help in some of your dust problems.

Are your logs frozen all the way? A partially frozen log will give more problems than a completely frozen one. How can you tell? If sawdust is freezing onto the side of the log, you probably have partially frozen logs. Not uncommon, but it gives big headaches. The best cure is to wait for it to either freeze or thaw. You can also reduce the lead a little for frozen woods.

The problem with slowing down the feed is that your sawdust is going to get finer. With finer dust and worn shanks, you'll have the dust falling out of the gullet and going down the side of the log. That will heat up the blade. Every other tooth will lower the power requirements, but I've never sawn like that. In effect, you reduce your feedrate by half, meaning twice as long to saw a log and double the operating costs.

D._Frederick · February 18, 2006, 12:50:46 PM

The old timers had a rule-of-thumb that you had to have between 2 to 3 horse power per saw tooth. With your 40 hp engine, you should have about 20 teeth max for optimum sawing. Replacing half of the shanks and teeth should give you better sawing performance.

For your 38 tooth blade you should have over a 100 hp for optimum sawing, with only 40 hp, you can not keep the saw cutting the chip size the gullets were designed to handle. When you reduce the feed rate, the chip size is reduced to the point were it spills out of the gullets and cause problems.

beenthere · February 18, 2006, 01:10:13 PM

D
This fits with what I used to hear from Stan Lunstrum (wrote the Circle Saw handbook often referred to here) when he would trouble shoot mills that were having blade heating problems. He said the sawdust was spilling out because the tooth bite was too small and the fine dust spilling would heat the blade (consistent with what Ron, you and others have stated). His recommendation would be to remove every other tooth. The results were apparently solving the problem and it fits with what you all are saying.
I used to hang around Stan and another sawmill specialist, Hiram Hallock, a fair amount, and listen in on their conversations. Also heard lots of stories told about different mills they visited and helped get out of trouble.

This Hiram Hallock told of building a portable circle mill that was hydraulic and sawed all around SW Wisconsin in the 50's. He lost that mill in the Mississippi river when a barge it was on took on water and dumped it off while moving the mill somewhere. Normally he towed it behind his truck and milled a lot for farmers and loggers. Wish I had a pic of that mill and how it was put together, but don't.

isassi · February 18, 2006, 03:01:18 PM

I stand fully corrected to the forum. That is what I love about this forum that we all have the opportunity to learn more. I also did a little looking and found references to running with half the teeth in place, and I would have sworn that would be a mistake...so little do I really know. :P One note I did see was that with no shanks or bits every other tooth, feed rates are more then cut in half for obvious reasons.

Buzz-sawyer · February 18, 2006, 03:55:04 PM

I do run every other tooth...BUT with a short tooth and shank in place....and the feed rate by no means is slower...I believe probably faster do to the power ratio per tooth ,I have more available horse power...definitely in regards to being in the cut, and reponding to a bog down ;)

Ron Wenrich · February 19, 2006, 11:50:42 AM

I think putting in a shank and a short tooth is a good idea. It helps to protect the shoulders on the saw.

sawguyver · February 19, 2006, 03:26:01 PM

This is great every body.

If you look at swing blade it seems to say less teeth for less hp.
My blade has only sawed 3000 bf since it was hammerd 8 years ago. It was just put on the saw this year. Too bad it was tensioned with the worn shanks. I'll change a few shanks just to see if they are tight. I don't think I'll try this if I have to rehammer. But as far as power it seems like its doable. I guess the proof will be in the pudding but its too cold this week. The wind really goes thru this place.

Ron
I have summer shanks (old and new) The first thing I'll try is to file them square and watch what happens.

Joasis
I also agree about this forum. So many differt angles really gives you a good picture I get "lost" in the archives.

Thank you every body ;D

beenthere · February 19, 2006, 03:43:04 PM

sawguyver
I like the pic of the mill shed, showing the truss over the header for extra support. Other than being exposed to the weather, it looks like a good idea. Reminds me of a much earlier discussion as to how to span the opening entry over the log deck going into the sawmill.

sawguyver · February 19, 2006, 04:41:09 PM

Yea

I didn't really pay attention at first but one day I looked up and thought " Yea makes perfect sense". That span is 20 feet with a steel rod in tension at the center (lots of tension around a saw mill :D ). The mill has been there since 1950. Waterproofing around the truss is a weak point, needs to be watched.

The building needs TLC. Lots to do this summer.

The previous blade owner mentioned never being able to saw hardwood with it. Since then its been hammered and this is a new mill for it. This info is second hand but was given to me anyway with the warning "don't expect too much" So here is this blade with this story. So, before cutting, hauling and loading my skidway with hardwood I thought I needed a game plan. The shanks are worn and its surprising it was tensioned like this. Hopefully this is the problem. Its always a question how much the other owner understood, maybe lots maybe nothing. They didn't have The Forestry Forum :D

sawguyver · February 21, 2006, 11:54:27 PM

I found a referance in a 1923 "Audels carpenters and builders guide" in which the text was prepared with the help of Simonds Saw Mfg. Co. They mention that in a mill where the power is limited the teeth should be reduced when sawing frozen and hard wood logs. They don't mention if they change the blade or remove teeth. :-\
I guess I'll keep reading. :P

Ron Wenrich · February 22, 2006, 05:48:03 AM

I take that to mean the width of the tooth can be reduced. It also takes less lead on frozen wood.

Buzz-sawyer · February 25, 2006, 08:44:58 PM

With shanks....it is much better to replace them in a cosistent manner....i.e ever other one.....remember they are the single most non mechanical cause of variation in your blade tension ...(the rim)tension...
using less teeth ....if effect means your horse power ratio is increased....same as Ron said about the size of the tooth...just less metal to cut and generate friction.....
there are some tricks for worn gullets...peening with a ball peen hammer and re installing...then latter using over sized shanks.......then after that wears out...never go to oversized shanks till you HAVE to....there aint no going back

sawguyver · February 26, 2006, 03:34:36 PM

Buzz-sawyer

Here is how I understand shanks and sawing soo far.

Horse power effects feed rate which effects how fine the sawdust is in the gullet which means the shoulders on your shanks are even more important when under powered.

So in an underpowerd situation with all teeth cutting slowly and fine sawdust pouring out the sides of your worn shanks your going to get inconsistant cuts or worse you'll heat the blade.

Therfore less teeth gives you more horsepower to keep your feed rate up and keep that sawdust where you want it. (better situation even if you don't change shanks). Sound good ???

I replaced one shank the other day to check its fit. It fit just barely tighter than the old one. I'm thinking it is because the old one was filed to square the shoulders and there is less material in the gullet which would make it weaker (or have less spring).

How can you tell if your shanks are oversized ???

If the blade misbehaves will I be able to put the old shanks back in ???

Well I'm going to saw frozen hardwood soon and I'll be ready with some ideas on what to try if I'm not getting good results.

I'll keep you posted

oakiemac · February 26, 2006, 03:39:59 PM

Sawguyver, my shanks have numbers stamped on the sides which tell you what gauge they are 8,10 or so on. Yours might have the same numbering system but I'm certainly no expert.

ex-racer · February 26, 2006, 04:03:25 PM

Sawguyver, my shanks also have the guage number and type (style) stamped on the side. For example, 3 - 8 means type 3, and 8 ga.

I found that my new shanks didn't fit any tighter than some of the old ones, and I had to peen some of them.

If a shank doesn't fit tight enough, it can be "expanded" by grasping it by the outer (grooved) edge using visegrips, lay it on an anvil, and use a ballpeen hammer around the inner edge.

Don't overdo it, 8 or 10 taps on each side will often be enough.

Ed

Ron Wenrich · February 26, 2006, 04:07:25 PM

Oversized shanks are stamped with a letter. For example, you might have a F 8 P. F is the style, 8 is the guage, and P is the oversize letter.

2 things happen to a saw that effects the oversize factor. One is that your shank can lose some tension over time. That is where the peening comes in to give it a little more spring.

The other factor is that you are pulling back on those sockets as you are sawing. Eventually, that stretches the sockets by a couple of thousandths. Your oversized shank will compensate for that difference.

Rarely have I had problems with shanks. I've put some in that were really sloppy and they held the teeth fine. Another thing I have done is to take a hammer a tap the end of the socket. Usually this is after I hit something that pulls the socket out. That generally will take care of the problem, but I don't recommend it as a cure all.

Horsepower effects how big a bite you can take with your saw. If your horespower isn't up to snuff, you can either reduce the # of teeth or slow your saw rpm. Slowing your saw RPM would mean you probably have to rehammer the saw. How many horses are you running?

If you got those old shanks out, you can put them back in. ;)

Jeff · February 26, 2006, 04:10:16 PM

I never, ever would peen a shank. You can tighten a socket up by gently tapping on the back of the shoulder. Over sized shanks will usually be stamped with an example as a F Pattern may say F8 where as the oversized will be F8 x1 or F8 x2

Some of the best running saws I have had, the shanks just slipped in easily. If you have to work at getting them in, especially if you have cleaned everything up and using lube, your sockets are to tight or your shanks to large. Having to force the shanks in will distort the rim, changing your tension.

Jeff · February 26, 2006, 04:10:50 PM

I see Ron and I get our shanks two different places. :D

Jeff · February 26, 2006, 04:22:14 PM

Rummaging around my stuff I seem to have found Ron's answer and mine on the same shank. :D

Ron Wenrich · February 26, 2006, 04:40:10 PM

Yep. Top one is oversized, the bottom on isn't.

Don P · February 26, 2006, 04:49:12 PM

I've never noticed an oversized shank, good to know if the need ever arises.

Another way of looking at teeth and feedrate is that each tooth is designed to cut between -1/10-1/8" of wood with each bite. The equation becomes saw rpm and number of teeth in relation to forward carriage travel = 1/8" per tooth per revolution. If you were cutting with 16 cutting teeth the theoretical ideal speed is around 2" of forward carriage travel per revolution of the blade.

Or, on my 540 rpm blade, each additional cutting tooth allows the feed to speed up the carriage by 67.5" or a little over 5-1/2 feet per minute. Thats why those high power production blades have teeth all over them and a fast carriage and a swingblade has 8. I could cut with one tooth, if you could ever tension for that, but my feed rate would be a board every 2-3 minutes.

I'm all the time talking to people who put a greater tooth blade on their underpowered tablesaw trying to correct the problem. Just the opposite is the real way to fix the problem, fewer teeth and slow down.

sawguyver · February 26, 2006, 05:36:13 PM

My saw is powered by a 1952 Chrysler Corporation's flathead 6. its turning at 1944 rpm. From what I'm told its putting out about 40 horses.

The saw itself is running at 636 rpm. ...(on the other side of that wall)

As far as I know the mill has sawn mostly soft wood and probably on average the size of log would be 20" in dia. I did bury the blade in a big pine and it managed it ok. I was taking my time with it and made mostly 12 wide material.

Does anybody have pictures of the tool that removes the teeth???

My tool is farm made and works good .....just wondering what a real one looks like ???