Weighing logs - hanging scales

mitch · January 16, 2003, 05:10:52 PM

Weighing logs with hanging scales using a hydraulic cylinder and pressure gauge
To mill large logs, I am adding a top saw to my old Vance Mill which has a wooden log carriage that is probably older (62) than I am. When I purchased the mill it had been in the open in a cow pasture for years. Anyway, I am somewhat concerned that the carriage could "break down" under the weight of a several thousand pound log. Unfortunately, I don't know what weight would break it. I had already setup a hydraulic cylinder for weighing round bales of hay so I just used it to weigh the logs. After weighing them, I machined two additional new trucks to place underneath the headblocks.
View of 2'' bore and 1" rod by 6'' stroke hydraulic cylinder supporting an eight feet by 40" (on butt end) red oak log. To determine the weight recall that pressure (P) is related to the weight (W) and the difference in the areas (A) of the bore and rod through the formula
W = P x 3.14 ( R^2 - r^2) where R refers to bore radius and r to rod radius. For this example W = P x 3.14( 1 - 1/4) or
W = 2.36 x P with P in PSI units.

The gauge reads 1400 PSI so the weight of this log is 3300 lbs.

Full size images are at
http://shagbarkfarms.com/Sawmill/HangingScales

Tom · January 16, 2003, 05:54:12 PM

That's some neat info. Sure beats picking the log up, standing on a bathroom scale and subtracting your weight. :P :-/ :D

Jeff · January 16, 2003, 05:54:51 PM

This is a good time to post something that slipped my mind.
The latest Forestry Forum Calculator. Another Ron Wenrich idea.

Ron should get the risiduals from this now so he can split them with me.

Everytime you DONT break your mill send Ron Money.

Everythime you DONT get an overweight ticket send Ron Money :D
Everytime you DONT break your log hauler SEND RON MONEY! :D

Here it is use it wisely. ;)

Log Weight Estimator

DanG · January 16, 2003, 07:21:18 PM

So, how much does Ron send back when we do break our sh*t? ;D

Seriously, though,....Thanks Ron. You be the Khaki-later GURU!

Captain · January 16, 2003, 07:38:55 PM

Jeff,

Pretty great, but how do I load it into my Palm Pilot?? :D

Captain

Jeff · January 17, 2003, 09:58:37 AM

I sure wish I knew how to write aps for palm pilot. we could put together a killer little software package for it.

Until I come up with a solution for that, just use it here. You should be checking into the forum at least 3 or 4 times a day anyway so it shouldn't be a problem. ;)

D._Frederick · January 17, 2003, 11:05:46 AM

Mitch,
On are No. 2 American, my father had rebuild the carriage with 4 X 6 fir timbers. While he had the carriage apart, he put 1/8 plate on the outsides and on the tops of the 4X6s. He did this more to protect the timbers from being gought up from peaves used to turn logs. We sawed 3ftx20ft fir loggs and never had carriage problems.
On your mill mandril sticking out 2 ft beyond the husk, why don't you put in an out board bearing? Better yet, a line shaft. We had a 10 ft line shaft on are mill, this gave more room around the mill to move lumber and be away from the belt.

RobK · January 17, 2003, 01:15:52 PM

Pretty great, but how do I load it into my Palm Pilot??
I don't know much about Palms but if it has a web browser on it that supports JavaScript all you have to do is save the log_weight.htm file and load it on to your Palm Pilot.

If there was a version of Perl for Palm, which alas, there is not yet, I'd write a version of this in Perl. I may just do that anyway...

And back on topic, that's a great way to weigh stuff...

Fla._Deadheader · January 18, 2003, 05:44:28 PM

OOOOOKAY, Been there and back. I figger this is for land logs. NOW, how much do I add for these wetlogs ????? How much would I also allow for the denseness of the old growth?? How would I apply it ??? Thanks for the great tool, Ron

mitch · January 19, 2003, 04:41:50 AM

Fla._Deadheader,
You have asked the right question!!!! A measurement is always preferred over a theoretical calculation. The density of logs of the same type can vary all over the place. If you know the density of the wood and if you have a reasonably uniformly tapered log then the weight can be calculated treating it as the frustum of a cone
weight = density x L x 0.2618 x(D^2 + dxD + d^2)/144
with density in lbs/cubit-ft and length in feet, the diameter of the big end D in inches and the little end d.
Example: red oak 65 lbs/cu-ft, L 8 ft, D 40", d 32"
Weight = 3690 lbs

dan-l-b · January 19, 2003, 04:54:25 AM

Why the worry on weight? If my machine won't pic it, it's too heavy. Or better yet, I just get a bigger machine 8) 8) 8)

Fla._Deadheader · January 19, 2003, 05:11:33 AM

dan-l-b, ever hear of D-O-T ?? They LIVE for weight checks. That was my concern, otherwise, slap another on the bed and MOVE AWAY !!! :D :D :D

dan-l-b · January 19, 2003, 05:29:53 AM

Yea, I've been pulled over a number of times, red tagged once, and now have my old 300 big cam cummins in storage waiting on an opportunity. DOT doesn't bother ya much if you have realitivly new truck, (avoid the scales) and keep up with your lights and stuff. I have really enjoyed your pics and posts Mr. Deadheader.

Don P · January 19, 2003, 06:50:49 AM

This is a more compact version of Mitch's rig from Northern Hydraulics. Could you suspend it from your trailer loader?

http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=4006970&storeId=6970&productId=7185&langId=-1

mitch · January 19, 2003, 11:30:42 AM

Hey Don,
I too have a "store bought" 650 lb capacity hanging scale... bought by my great great grandfather to weigh bales of cotton prior to the Civil War. Not too good for weighing logs as a bale of cotton usually weighs 500 lbs. We used the scales to weigh the picked cotton... it takes 1500 lbs of cotton locks to make a bale after ginning out the seeds. Also great for weighing hogs at butcher time provided the hog weighed less than 600 lbs. Just weighed the head then and multiplied by 10.

Don P · January 19, 2003, 12:32:46 PM

Neat,
Dad has one of those hanging beam scales up on the wall at their house. It's of more modern appearance, flat stock with marked notches for the weight to stop on. I think theirs was used mainly to weigh sheets of tobacco, but they did grow some cotton.
I saw on your Bio you were a Physics prof. at UNCC, did you ever know Dr Githens over at Duke? He wrote our Quantitative Physical Sciences book for 9th grade, his wife was my English teacher. I did their handyman/yardwork for a few years in jr and high school. Never had much of a clue in class till I got him to 'splain stuff while we worked together around their place. He had some neat stories of being a telegraph operator on steamers on the Great Lakes in the early days before voice radio. I hope to end up with one tenth of what was in that man's head.

Bro. Noble · January 19, 2003, 01:37:46 PM

Don,

My folks have scales like you describe. In addition to calling them 'cotton scales' they also call them 'steelyards' but I'm not sure that's how they spell it :D. Did that name come from weighing metal in a steel yard?

Those things would be good for teaching fulcrums and levers to dummies like me ----- you can see what's going on. :P

Noble

Fla._Deadheader · January 19, 2003, 02:03:13 PM

Thanks, dan-I-b. Glad that I can contribute in some way, to all the good info on this forum.

Tagerts_crossing · January 19, 2003, 02:07:52 PM

Hey guys, I think they are called STILYRDS. We have some here on the farm and that is what my grandma called them years ago. They were what most farm familys used around here to trade with years ago. John

dail_h · January 19, 2003, 02:50:51 PM

OK GUYS,
Splain something to me please.Thats a really kool way to weigh logs,have to be careful,git my ways mixed up.I can sorta follow the idea, but who'da thunk a sawmill guy woul have figured that out ???Way to go Mitch.Handy stuff to know.Now for the part where I need help----if I wasto say want to weigh the little lady,what size chain &cilinder should I use,and do you think she would get mad if my 3600FORD tractor&boom wouldn't pick her up?Should I start with something bigger????HELP.It aint loaded till no more will stay on.

mitch · January 19, 2003, 03:00:10 PM

D._Frederick,
Thanks for your as usual knowledgeable comments about circle mills. I suspect your Dad's No 2 American Saw Mill was of heavier construction than the lightweight "tractor/farm" Vance mill that I have. Mine was probably made before WWII since it has drop dogs. All mills that are around here (NC) have ratchet dogs. Prior to WWII most farm tractors had less than 40 HP. The legendary D JD only had 42 HP in its last year of production (1953).

I should and intend to replace the flat belt drive with 16-18" 4 groove C belt sheaves placed near the outside mandrel bearing...this would eliminate the flexing of the mandrel under heavy belt load. In the meantime last week the old G JD was cutting a full 19.5" of dead red oak at a reasonable feed speed. It is hard to "fix something that is not broken".

bull · January 19, 2003, 05:09:45 PM

Hmmmm whole lot of figurin x+y+z= ONE BIG HEAD ACHE

  HERE A SIMPLE FORMULA
  LITTLE LOG = not to heavy put it on your shoulder
  MEDIUM LOG = GET OUT THE PEAVEY
  BIG LOG = GET ANOTHER PEAVEY AND A HELPER
  BIGGER LOG = BETTER GET THE TRACTOR
  BIGGEST LOG= SELL IT TO ANOTHER MILL SO YOU CAN GET BUSY CUTTIN ALL THE OTHER MEDIUM LOGS YOU'VE GOT IN THE YARD+