Chain tension on long bars

[zogger]

Yes, there are several.

I don't think that is practical at all - there simply are too many variables involved.

There are only a few that are most likely critical. It's all a matter of fine tuning and degree run against practicality in the field. And after awhile, you will come to know your saw and bar better and how it works in the cut, plus as a consumer, you can be better informed in advance of purchase.

Guys here go to great lengths..say..to measure a new piston at a lot of different places, fine tune what they cut out of the ports, etc, all in the name of gaining a percent improvement here, a percent there, etc. The easier ones can be done..well, easy..but then if you want to go further, it would be nice to have actual measurements as opposed to guesstimates.

Hmm..an analogy..hmmm. dudes who shoot. You can use stock ammo, try different brands, or really get into it and develop custom reloads for specific reasons, then once that base work is done, you can then proceed to mass produce them, or in this case, get to cutting. I have a relative who is really into that, every round he makes is a freaking work of art, because he precisely measures..everything involved. Guys who already know what they are doing hand over their pieces and give him a set of specs on what they want out of some rounds, he fine tunes it until it is met, and still fall within a safety range. High performance is high performance, it doesn't matter the discipline.

He would be the equivalent here of the big name saw hotrodders. And it is primarily because he measures, tests, verifies and keeps meticulous records, for decades now. He doesn't just guess at things. Even an educated guess is not as good as a precise measurement.

It is just theoretically another form of tuning, it could be as hard or as easy as anyone would want to go with it. And it would be interesting to see bonafide comparisons, this brand bar and chain versus that one, etc. So sure, tons of variables, but proly only a big few or so that really matter a lot.

Stuff never gets better until realistic engineering gets thrown at it, yes? That's really my whole point in this. Say you as joe saw and accessory consumer, if you had real specs to look at, as in this bar was 10% smoother/less friction and resisted wear and kept to gauge better by such and such amount given similar loads..which bar would you buy?

There's guess, then measure, two different things once you start to get technical, and that would also help to dismiss "brand blindness" as per performance. With a lot of experience, sure, you can become a good guesser, but you'll never beat a real accurate precise measurement.

 

[GASoline71]

You must be an engineer...

Gary

 

[GASoline71]

On long bars (actually ALL bars)... I hold up on the bar tip while tightening. Tighten to where the chain just touches the bottom of the bar... and that's it. No sag, no drag... I also don't tighten it "a little more" either. "A little more" means more heat in the bar tip...

Gary

 

[zogger]

rest it on wood

On long bars (actually ALL bars)... I hold up on the bar tip while tightening. Tighten to where the chain just touches the bottom of the bar... and that's it. No sag, no drag... I also don't tighten it "a little more" either. "A little more" means more heat in the bar tip...

Gary

I rest the tip on a chunk of wood to keep that up angle.

Huh, another invention, two bar adjusters, one for out, another for that up angle.

Maybe if they weren't built so sloppy you wouldn't need to hold them up or rest them up. Seems like they just want the two bar stud nuts to do all the work of holding the cover and brake band assembly in place, along with the bar and dawgs if they are there. Make them separate, with different attachment nuts, and you could make the bar/chain adjustment a little more precise and most likely easier.

I just find it odd with all the other precise measuring that goes on, bar and chain drag is sorta neglected into the guesstimate field. I mean it works OK obviously, just pondering on things... I like pondering..many moons ago I had a bike shop. I was an avid off road bicyclist, but they didn't sell anything suitable, it just didn't exist. If you wanted good big fat tires, you only got one, two, or three gears, which just wasn't enough, not dealing with extreme conditions and only 1/3 horsepower "motor". If you wanted a lot of gears, you only got skinny wheels and tires. I went, WTH, this sucks...I was tired of walking back with dented wheels and forks from way down jeep roads or snowmobile trails. So I built a working prototype of what are now known as "mountain bikes". MAN that was fun. Had tons of people wanted to buy that bike from me. Used it for a bragger parked outside my shop on the sidewalk.

Wish I had made some serious coin off that idea....good at building, suck at marketing..then anyway. Learned some stuff since then.

 

[oscar4883]

You invented the mountain bike? IMO your theories are interesting but way over thought. The system that saws have works great. Its simplicity is what makes it a good piece of engineering IMO. Pefect this and perfect that, doesn't exist or need to be. Whats next, a study of the perfect body mechanics for cutting? Protractors, for setting up your cuts? Not knocking you, just saying.

 

[Locust Cutter]

There are only a few that are most likely critical. It's all a matter of fine tuning and degree run against practicality in the field. And after awhile, you will come to know your saw and bar better and how it works in the cut, plus as a consumer, you can be better informed in advance of purchase.

Guys here go to great lengths..say..to measure a new piston at a lot of different places, fine tune what they cut out of the ports, etc, all in the name of gaining a percent improvement here, a percent there, etc. The easier ones can be done..well, easy..but then if you want to go further, it would be nice to have actual measurements as opposed to guesstimates.

Hmm..an analogy..hmmm. dudes who shoot. You can use stock ammo, try different brands, or really get into it and develop custom reloads for specific reasons, then once that base work is done, you can then proceed to mass produce them, or in this case, get to cutting. I have a relative who is really into that, every round he makes is a freaking work of art, because he precisely measures..everything involved. Guys who already know what they are doing hand over their pieces and give him a set of specs on what they want out of some rounds, he fine tunes it until it is met, and still fall within a safety range. High performance is high performance, it doesn't matter the discipline.

He would be the equivalent here of the big name saw hotrodders. And it is primarily because he measures, tests, verifies and keeps meticulous records, for decades now. He doesn't just guess at things. Even an educated guess is not as good as a precise measurement.

It is just theoretically another form of tuning, it could be as hard or as easy as anyone would want to go with it. And it would be interesting to see bonafide comparisons, this brand bar and chain versus that one, etc. So sure, tons of variables, but proly only a big few or so that really matter a lot.

Stuff never gets better until realistic engineering gets thrown at it, yes? That's really my whole point in this. Say you as joe saw and accessory consumer, if you had real specs to look at, as in this bar was 10% smoother/less friction and resisted wear and kept to gauge better by such and such amount given similar loads..which bar would you buy?

There's guess, then measure, two different things once you start to get technical, and that would also help to dismiss "brand blindness" as per performance. With a lot of experience, sure, you can become a good guesser, but you'll never beat a real accurate precise measurement.

I'm no engin-eer, (sic), but I get what you're aiming at, (couldn't resist). As an reloader and shooter, I have a list of specs for all of the different calibers that I load and the arms that fire them. Each box that I roll up has an accompanying "load sheet" that I transcribe with the various components, recipe and a host of critical measurements, notes and observations between the brass and bullets. That way I know exactly what went in to each batch, (including relative humidity that day) and then know what I should expect on the firing line when I set out to do some testing. I never shoot factory anything anymore (except rimfire of course) for that reason amongst others. I agree it would be neat to know what was going on with the chain (a tensiometer perhaps) and have a safer way for the un-initiated to learn correctly from the start. You don't just start pouring powder into a casing until it "feels right". However, as was also observed, it would be somewhat difficult to isolate and account for the several variables in this equation just for one bar, let alone a standardized guide of them. It would be a most worthwhile task though.
-Bryan

 

[Locust Cutter]

You invented the mountain bike? IMO your theories are interesting but way over thought. The system that saws have works great. Its simplicity is what makes it a good piece of engineering IMO. Pefect this and perfect that, doesn't exist or need to be. Whats next, a study of the perfect body mechanics for cutting? Protractors, for setting up your cuts? Not knocking you, just saying.

LMAO!!!!! Actually,... The manufacturers have been doing that for a long time. That's why we have "Ergo handles" and the different makes have various unique handle and bar angles. I love my McCulloch, but my MS660 is much more comfortable to run (not even taking into acct the lesser weight and A/V induced fatigue) with the angles that the saw is held at.
-just saying

 

[oscar4883]

Good point LC, but I'm not talking about a simple handle angle, or ergonomics in general. I mean taking it to the extreme. If its someones thing to study all these little details more power to them. They are probably much smarter and more patient than I am. lol I suppose I am just a little on the simple side. Some guys really sweat the most subtle differences between saws, chains, etc., when working on you sharpening techniques, cutting style, or climbing style, are really the things that will make a job safer and easier. IMO

 

[zogger]

cut efficiently

Good point LC, but I'm not talking about a simple handle angle, or ergonomics in general. I mean taking it to the extreme. If its someones thing to study all these little details more power to them. They are probably much smarter and more patient than I am. lol I suppose I am just a little on the simple side. Some guys really sweat the most subtle differences between saws, chains, etc., when working on you sharpening techniques, cutting style, or climbing style, are really the things that will make a job safer and easier. IMO

Well, that's the whole point, to cut efficiently. I'd just like to know which bars and chains combos, combined with a tension adjustment, really works the best, something that can be proven, not just anecdotal observations. If there was a tool for this, plus some shop studies, it would be real fast to get the perfect combo for your needs. It's not like you would have to take twenty minute every time you fired one up, you'd develop what worked in advance for your saws you run and what you are cutting the most. It tends to be a lot of the same for most guys.

And as I pointed out, there exists "brand blindness" when it comes to tech things as well. Who needs that, I don't, I ain't loyal to some advertising schtick, I'd rather just look at a page of specs and go from there. If brand x,y or z claims they are the best, prove it, let's see some numbers and independent tests with bars and chains. I bet there's a LOT of variance that goes on outside the powerhead with saws and cutting. If you can pickup an extra ten per cent efficiency just by a little tweak, well, why not? And instead of hit and miss, I think it would just be better to have some afctual numbers and studies to go by, then a tool for really adjusting tension precisely, both for when you first start, then a few cuts later when things are warmed up. I mean all of us use kentucky windage on that now, just saying it could be better, and probably with not much effort once the studies are done.

I am not in a position to do such studies here, else I might give it a whack. I don't have a machine shop or a buncha different sizes of bars and chains and saws and precise measuring apparatus and all that.

I bet the bar and chain guys do, but they keep that stuff trade secret, etc.

Anyway, just been thinking out loud, no biggee, don't claim to be anything but a raw rookie here. I just have always enjoyed looking at something and wondering how to make it better, or to do something a little different, to scratch an itch as it were.

 

[Buzsaw]

This is what I do...just my 2 cents. Snug the chain, snug the bar nuts so the bar can move up or down (not loose). Rest the nose of the bar on wood, plastic, etc.,(might damage tooth or rip your bench up). Grasp the tank handle and tip up , tighten the bar nuts so that the bar doesn't. Test the tension...1/4" sounds good. What I do next is place a screwdriver or your bar nut wrench shaft behind a tooth and push the chain. Chain should rotate smoothly...if you over tighten, it will be hard to push. Too loose...the chain will come off. Tighten bar nuts.

 

[zogger]

There were several

You invented the mountain bike? IMO your theories are interesting but way over thought. The system that saws have works great. Its simplicity is what makes it a good piece of engineering IMO. Pefect this and perfect that, doesn't exist or need to be. Whats next, a study of the perfect body mechanics for cutting? Protractors, for setting up your cuts? Not knocking you, just saying.

Oh, I want it simple, just verifiable, not guesstimates. joe blow or joe big company claims bar x and chain y is the best at this line drawing or picture in the manual showing "the perfect chain adjustment" setting... cuz he or they says so.., uh huh... prove it, show me the studies and some numbers.


bikes--there were several independent efforts going on in roughly the same time frame to develop these sort of bikes. I was working completely on my own on the opposite coast outside the main area of interest at the time, which was California, and quite frankly, I was completely ignornant of those other efforts.

I just knew what I wanted, it didn't exist for sale anyplace, I had a shop and a ton of parts and some spare time now and then... so I built one.. The downhill sand dune racers in Cal and so on were working on them, whereas I wanted a woods and trail bike that worked and had extreme low gears and robust everything so the durn thing wouldn't break when in rough use. Earlier models of "cyclocross" bikes had shoulder carrying bars for traversing rough and muddy terrain you couldn't ride across, but all had wussy wheels, being pizzpoor derivatives of light weight road bikes.

I was in negotiations both with patent guys and also a taiwan manufacturer when the entire scene exploded into commercial production, (the history can be found online, my part isn't there as I wasn't part of any organized scene then with lots of records, other than I know a certain big builder saw my working prototype..never offered me a job either...) so I just went heck with it, who cares, didn't have near the money to pursue it further into a commercial enterprise, and just gradually lost interest.

The one I built eventually got stolen, but I can get them for free or ten bucks today used, so I really don't care all that much, just interesting that big breakthroughs like that apparently hit humans at roughly the same time.

It was just *neat* man, I mean serious ear to ear grinning *fun*, get to use something no one else ever had before.

 

[oscar4883]

Thats wild zogger. I rode for many years. Still do on occassion but now the only bike I have is a single-speed.

 

[2dogs]

Oh, I want it simple, just verifiable, not guesstimates. joe blow or joe big company claims bar x and chain y is the best at this line drawing or picture in the manual showing "the perfect chain adjustment" setting... cuz he or they says so.., uh huh... prove it, show me the studies and some numbers.


bikes--there were several independent efforts going on in roughly the same time frame to develop these sort of bikes. I was working completely on my own on the opposite coast outside the main area of interest at the time, which was California, and quite frankly, I was completely ignornant of those other efforts.

I just knew what I wanted, it didn't exist for sale anyplace, I had a shop and a ton of parts and some spare time now and then... so I built one.. The downhill sand dune racers in Cal and so on were working on them, whereas I wanted a woods and trail bike that worked and had extreme low gears and robust everything so the durn thing wouldn't break when in rough use. Earlier models of "cyclocross" bikes had shoulder carrying bars for traversing rough and muddy terrain you couldn't ride across, but all had wussy wheels, being pizzpoor derivatives of light weight road bikes.

I was in negotiations both with patent guys and also a taiwan manufacturer when the entire scene exploded into commercial production, (the history can be found online, my part isn't there as I wasn't part of any organized scene then with lots of records, other than I know a certain big builder saw my working prototype..never offered me a job either...) so I just went heck with it, who cares, didn't have near the money to pursue it further into a commercial enterprise, and just gradually lost interest.

The one I built eventually got stolen, but I can get them for free or ten bucks today used, so I really don't care all that much, just interesting that big breakthroughs like that apparently hit humans at roughly the same time.

It was just *neat* man, I mean serious ear to ear grinning *fun*, get to use something no one else ever had before.

You must be talking about the late 1960s or early 1970s. I live in an area where mountain biking was in its infancy by the mid 70s. The mountains of the SFO bay area and Santa Cruz led to many 10 and 15 speed fat tire montain bikes by 1975 or so. A very good friend of mine welded up many early 1, 3, and multi-speed bikes including the first cantilever 1 gas shock frame that was sold to a major manufacturer.

How about some pics of your invention Al?

 

[Krokit]

since were on the subject of bars and chain tension,how tight should you tighten the bar nuts?im mean realy crank them down or just snug them up.Is there an actual torq number for this.

 

[D&B Mack]

since were on the subject of bars and chain tension,how tight should you tighten the bar nuts?im mean realy crank them down or just snug them up.Is there an actual torq number for this.

When I can feel the teeth through my jeans. :cool2:

 

[Krokit]

its funny that i know what your talking about.

 

[zogger]

In the 70s

You must be talking about the late 1960s or early 1970s. I live in an area where mountain biking was in its infancy by the mid 70s. The mountains of the SFO bay area and Santa Cruz led to many 10 and 15 speed fat tire montain bikes by 1975 or so. A very good friend of mine welded up many early 1, 3, and multi-speed bikes including the first cantilever 1 gas shock frame that was sold to a major manufacturer.

How about some pics of your invention Al?

No sorry, I don't have any pics, not named Al either....

I had one pic a long time ago but when I broke up with a girlfriend I had at the time, she got the pics, long lost, no idea where she is at now. And as I admitted, guys on the west coast were building prototypes one off models as well, but at the time I did not know this, and I had certainly never seen one or a picture of one. I just knew what I wanted.

It really wasn't all that hard. After one (controlled) spill with yet another bent rim (went over a hill late winter/early spring, too much ice in some shadows on a steep hill with bad news at the bottom, so layed it down, pushed it away, bike went off into a washout and smashed into some rocks), I got steamed, and set out to fix this problem. I started going through my junk, and found a one speed frame that fit a ten speed two sprocket crank, perfectly! I got to then use normal chain as well. I knew I could do it easy then. That solved a ton of problems right there, and no brazing or welding needed. Instead of modding a ten speed to be stouter and take wider wheels, I modded a one speed to have ten gears including some mambo low ones.

I then went through my stash of wheels and found the beefiest box rim for the rear I could, and unlaced it from the one speed old cruiser coaster brakes styled hub. Then I got the beefiest 10 speed styled rear hub I had, picked out longer spokes, laced it up, stuck them through the rim holes, a little snip and a little die action later, I got that to fit, got the nipples on and trued it up. The front was just the front, needed nothing other than replace to box rims. Then I fabbed a little wide side pull brake assembly holders and fit them to the forks, front and rear, seems I used some old "stingray" brakes, and I used midrange shimano stuff for the derailleur and front changer. The free wheel itself I rebuilt with every other tooth out gear for the last two larger low gears, that was the only oddball thing I didn't have and I had to buy. Had to go to box rims obviously because they are designed for the caliper brakes. Broke a chain, ran it around, saw how much more I needed because of the oversize rear sprocket, added some links, done. And that was about it, a few coats of paint on the frame then, etc, cushiest seat I could find, took off, worked perfectly.

Here's something totally different that I do have a pic of, just took 'em, another (minor) innovation. It's called a "schmuck" used in the tradeshow industry for the last tweak on wingnuts, critical in aligning exhibit/display panels to get them perfect. Worked in that biz for some years.

We used one off models for years, usually just cut off square tubing with some tape for the handle, one day I decided to improve on it and get a small production run made, so I did, just designed it and took it around to shops for quotes until I could afford it. Had a run of fifty made, the minimum. Sold em all real quick like, and that's it, no more. What was unique on mine was an actual production model, plus added a chuck so it could be used in cordless drills as well, which speeds it up a lot, especially on teardowns. Plus the oh so spiffy knurled handle

Works really good, had dudes coming up to me years later wanting more. I just didn't care, just something *I* wanted for my work at the time and a way to pay to have it made, lacking a machine shop. I kept two. It's made from some hard aluminum. I think I would rather it was chromed steel or stainless steel but that was the cheapest I could afford at the time.

Just itches needed to be scratched. I imagine any number of guys here have some neat inventions or tools or whatevers they have built, because what they wanted didn't exist in the market, or were too expensive, or didn't quite do what they wanted them to do. Modding is modding!