lose chains...

[ENTS]

I don't lose a chain very often but you're right, if they are too loose, then one could lose them.   ;)

THANKYOU.  You know what I mean.

 

[Cedar Savage]

A loose chain tears up a bar pretty fast...peens a dip in the bar just before the roller nose, after that, the bar wears out chains, & then ya got to start all over, & buy both new...$

[gspren]

Well, this should be easy enough to prove one way or the other. Someone needs to measure the link of a chain cold, then check it hot. I'm betting you can't measure the difference.

  I'll take that bet if you want to lay out some cash! As an old machinist I've got some precision measuring equipment. Now to get practical the chain probably grows in length a bit more than you would think but so does the bar length so most of the time its no big deal unless you get a chain hot without heating the bar.

[ENTS]

gspren,

I'd love to see the results.  If you can do it, photo document it.  Good luck with it.


Hope all is wll,

[gspren]

gspren,

I'd love to see the results.  If you can do it, photo document it.  Good luck with it.


Hope all is wll,

I have done quite a few heat shrink assemblies through the years and it is not that hard to calculate the change, in the old days we looked up the expansion of various materials in a machinist handbook but now you can look it up on the computer, then figure your starting and ending temps. The chain will change in temp a few hundred degrees F. and with a 20" bar the chain is about 48" long. I'm heading for the mountains in a few minutes  8) if no one can figure it I'll do it next week.

[nmurph]

A chain should not change "a few hundred degrees." I doubt they get much above 200°F. I have an IR gauge and maybe I can reading.

[gspren]

 I just went to a linear thermal expansion calculator and a length of 48" heated from 40 degrees to 240, or a 200 degree change would lengthen by 0.1536 or a bit over an eighth of an inch, certainly measurable but with the bar also expanding some not a problem. My original statement was that I COULD measure the change and I still could even at a 100 degree change. 8)

[shootingarts]

I just went to a linear thermal expansion calculator and a length of 48" heated from 40 degrees to 240, or a 200 degree change would lengthen by 0.1536 or a bit over an eighth of an inch, certainly measurable but with the bar also expanding some not a problem. My original statement was that I COULD measure the change and I still could even at a 100 degree change. 8)

Yeah, I figured I could measure the difference in length of a single link at the real temperature changes chains see myself, but I didn't figure it was too relevant that I could measure growth with my ten-thousandths mikes.

I think a chain does grow enough to make a slightly loose chain seem very loose but I don't have the testing or math to back it up. The bar should heat up and expand at a considerably slower rate than the chain and of course all of the length increase will seem to be at the bottom of the chain loop when looking at a hot chain.

If somebody can model mathematically or in a CAD program two legs of an angle or an arc between two endpoints 24" apart we could get a pretty good answer. Start with the center point of the arc or the axis of the angle at .05 below the end points and then add .10" to the length of the arc or the two legs of the angle. How far is the centerpoint below the two endpoints now? Seems to take very little adjustment between slightly loose and very loose on a saw chain.

Hu