band tension adj. failure

[mike p]

well yesturday as i was milling i had problem with my hyd band adjment
the guage wood not read at all so my tension was a guess not good
called the factory got an idea of problem

[mike p]

so i took it appart & put in new orings
success

[Kirk Allen]

What did they think caused the old O-rings to go bad?  Moisture?

[mike p]

they didnt give a reason just said that that is common repair problem. i suspect that sawdust getting in there worn down the out side oring as sawdust e=was pilled up aganist the piston on out side .
a neibor of mine has a woodmizer & he had a simlar problem with his hyd pressure thingey & it only required new orings allso.
my pressure when operating runs betwen 600-800 lbs on hyd pressure guage ,tops out at 1000lbs. his woodmizer guage has a green & red zone & its way up there like 2500lbs  why the big difference

[chaikwa]

my pressure when operating runs betwen 600-800 lbs on hyd pressure guage ,tops out at 1000lbs. his woodmizer guage has a green & red zone & its way up there like 2500lbs  why the big difference

I don't know why there is a difference either, but when I built my mill I was also told that the optimal pressure for the band, (by the reading on my gauge), was 2300lbs.

chaikwa.

[JP Sinclair]

I'm surprised that mill runs on 1000 lbs max pressure.  My LT40 likes it around 2200-2400.  At 1000, the band would slip for sure.  May be differences in feed rates too.  Slower at 1000 may work ok. 

[mike p]

well my oring repair lasted one day so i called the Kasco factory again & got the part # for the seals now have to go get em
i asked about the pressure diff & he said i should only be running at 400-500 lbs as the size of the cly is different compaired to woodmizers & there for pressure is different
i dont follow that as psi i thought is psi regardless or so i thought

[Kirk Allen]

It is!  PSI is PSI, big cylinder or small. 

[mike p]

well i found out orings rated for hyd use are different that orings you buy in an assortment
got some from the case dealer they are thicker & soposed to be better rubber
any way they are holding as we were milling most of the day with no problems other than hitting barbed wire in 3 logs. & i logged these trees, theys no old fence anywhere around but iguess 60+ years ago there was

[joasis]

It is!  PSI is PSI, big cylinder or small. 

Ok now....I don't know the diameter of the cylinders were are talking about, but the "force" it applies is directly proportional to the pressure. A 2 inch diameter cylinder would have an "area' on the piston of 3.14 inches, and at 500 psi, exert 1,570 ponds....at 2400 psi, the force would be 7,536 pounds, or 3 and 1/2 tons. A 3 inch in diameter piston with 500 psi would exert a force of 3500+ pounds and at 2400 psi, nearly 17,000 pounds, or 8 and 1/2 tons.