Re: Blade tracking problem
On Wed, Feb 23, 2022 at 05:26 PM, John Vreede wrote:
One way I've found to look at the wheel position and tracking is to use a bit of thin string (braided fishing line is ideal) instead of the blade.? Make a loop ~62" long (a bit smaller than the 641/2" std blade loop length so you can stretch it some when tensioning) and position it in the middle of the land?where the blade runs on the bandwheels.? Tension it up quite tight and see where it passes through the guides. It should be where the middle of the blade runs and not touching either side guide roller and should be clear of the back support roller by about 1/4".??
I bet you it's not!?
That would work well provided the string was positioned centered on the wheels Another problem with my saw was that the blade guides did not have enough adjustment. I milled one of the slots a bit wider to get it closer. I'm guessing my blade is still deflected down maybe and 1/16" but it's close enough that it doesn't cause any problems. If all these saws were made the same, a person could? design an after market blade guides but I'm guessing there is a lot of variations. With properly designed blade guides setup would be super easy! Picture this!?
1) Get the blade tracking correctly
2) install the guides with zero blade deflection and the top bearing just touching the back of the blade.
3) then rotate into position.?
It would easy to design but hard to make it fit all saws.?
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Re: Blade tracking problem
Hi all It's actually quite astounding that there are so many faults with these saws, and it's not?just one brand, it's all? of them. If they were making lathes no-one would buy them!?? Part of the problem is that there are so many adjustments that almost anything can be MADE to cut, but when it comes to cutting accurately these adjustments sometimes don't work. and you have to resort to drastic measures like Mark did. One way I've found to look at the wheel position and tracking is to use a bit of thin string (braided fishing line is ideal) instead of the blade.? Make a loop ~62" long (a bit smaller than the 641/2" std blade loop length so you can stretch it some when tensioning) and position it in the middle of the land?where the blade runs on the bandwheels.? Tension it up quite tight and see where it passes through the guides. It should be where the middle of the blade runs and not touching either side guide roller and should be clear of the back support roller by about 1/4".?? I bet you it's not!? Taking off one or both side guide rollers will show where the blade wants?to run. That's how I found where to silver-solder the bits,?to position the guide rollers, when making a new set of guides Like Mark found, if the rear support rollers are too far forward (esp the bottom one), the blade comes off, when you increase bow weight to make it cut quicker. This is because it's bending the blade across its 1/2" width and when the weight comes on, the blade pivots around the rear support roller and jumps off the bottom wheel (I use the saw with the head vertical and the viewer standing with the vice handwheel in front of them for any up-down/, back-forward bottom-top etc directions)? - jv?
On Sun, Feb 20, 2022 at 02:05 PM, John Vreede wrote:
Then the bottom wheel is moved in or out on the drive shaft to get it to also track <0.040" from its rim.? You do this by changing the length of the spacer between the bottom wheel and the gearbox out bearing.
?
This is excellent information. I have a new saw (actually over a year old now) with some discrepancy between the ledge of the upper and lower wheels. if I remember right it's about .030" further out on the lower wheel and in my opinion it's not enough to worry about. I remember thinking the only way to fix this would be to move a wheel in or out but I wasn't really sure which wheel.?
I have something to add about blade tracking that is worth looking at. When I got my saw it seemed like everything was set up and ready to go so I started using it without making any adjustments. Then I started increasing the weight (it was cutting very slow) and as a result the blade started falling off. Most often this mutilated the blade and made it unusable. After the third blade I realized I needed to take a closer look. I found what I thought was the problem and then confirmed this with other saw manufactures.
First, (as you said John) the blade tracking need to be set with the blade guides removed. Then when the guides are installed they should twist the blade along the center line without deflecting downward or to the left or right. Ideally the bearings in the guide should only contact the back of the blade while cutting although it needs to just barely kiss the bearing all the time. Very slight pressure is also fine.?
The problem on my saw was that the blade guides were deflecting the blade downward nearly 3/8". With the guides set correctly the saw would not cut deep enough. The cover near the top wheel hit the base. Even when I removed blade cover the upper frame hit the switch housing before completing the cut. After doing a little research I realized my saw was defective. I looked at two other older saws that did not have this issue. I suspect this problem is a result of a bad setup at the factory. Maybe the pivot point for the head was not located correctly. In reality the pivot point on my saw needs to be dropped over 1/4".?
I ended up putting a 1/4" steel plate under my vise. This elevating plate raises the stock enough so that the blade can complete the cut without being deflected significantly by the blade guides. Since making this change I can increase the downward pressure to full. Sometimes the saw stalls but the blade never comes off. In fact, I have had the same blade on my saw almost a year now. It has cut a LOT of steel.?
I had a bunch of these elevating plates made (laser cut) and have sold over 60 of them (apparently quite a few saws have this defect). I currently have one plate in stock but if there's enough interest I can have some more made. When the price of steel went nuts I raised the price from $29.50 to $39.50 but honestly it's barely worth my effort. After the cost of steel, laser cutting and shipping I'm about $2 ahead. Let me know if your saw needs this plate. If there is enough interest I'll have more made.?
Mark
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Re: Duracraft 4x7 bandsaw
Hi Joe. I doubt that they're hard chrome plated as this would be a way for them to fail though they could be. Ordinary bearings are just finish ground from some pretty high ally steel which has a lot of chromium in. Cam follower bearing are meant to have things rubbing against them so even the black finish will be good - jv
Thanks for all the info.
I have tried to relube them.? The top(with the blade slot) has a hole for lubrication.? The other side has the plug installed.? I tried to spray some ;ithium grease from a spray can with a straw.? Not a good fit but some went in. It is getting better.? Cargill has some information.? Talk about a 1/8" press fit grease nipple.
Size:? It appears the are CFE10 (22mm diameter).? The measurement is closer to that then a CFE7/8.? I would have expected it to be inch be it appears metric.? They may not be original.? I bought some CF10 and the fit good.? I might try a CF7/8 if I can find it cheap.? I have been measuring with my cheap digital calipers.? I do not not have a good knowledge of clearances so it is easier to buy a cheap one to test fit.
Possible sizes are CFE10, KR22, and maybe a CFE7/8 (it is a little bigger)
I will write more later.? Got to change frier oil and fix a car air conditioner.? When I get home putting the saw together
Finish:? the saw cam followers have a chrome? finish.? It is shiney at least.? I have only found CFE's with a black oxide finish.? Would that be OK?? I am not sure if it is realy chrome to make it harder.
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Re: Duracraft 4x7 bandsaw
Thanks for all the info.
I have tried to relube them.? The top(with the blade slot) has a hole for lubrication.? The other side has the plug installed.? I tried to spray some ;ithium grease from a spray can with a straw.? Not a good fit but some went in. It is getting better.? Cargill has some information.? Talk about a 1/8" press fit grease nipple.
Size:? It appears the are CFE10 (22mm diameter).? The measurement is closer to that then a CFE7/8.? I would have expected it to be inch be it appears metric.? They may not be original.? I bought some CF10 and the fit good.? I might try a CF7/8 if I can find it cheap.? I have been measuring with my cheap digital calipers.? I do not not have a good knowledge of clearances so it is easier to buy a cheap one to test fit.
Possible sizes are CFE10, KR22, and maybe a CFE7/8 (it is a little bigger)
I will write more later.? Got to change frier oil and fix a car air conditioner.? When I get home putting the saw together
Finish:? the saw cam followers have a chrome? finish.? It is shiney at least.? I have only found CFE's with a black oxide finish.? Would that be OK?? I am not sure if it is realy chrome to make it harder.
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Re: Blade tracking problem
On Sun, Feb 20, 2022 at 02:05 PM, John Vreede wrote:
Then the bottom wheel is moved in or out on the drive shaft to get it to also track <0.040" from its rim.? You do this by changing the length of the spacer between the bottom wheel and the gearbox out bearing.
?
This is excellent information. I have a new saw (actually over a year old now) with some discrepancy between the ledge of the upper and lower wheels. if I remember right it's about .030" further out on the lower wheel and in my opinion it's not enough to worry about. I remember thinking the only way to fix this would be to move a wheel in or out but I wasn't really sure which wheel.?
I have something to add about blade tracking that is worth looking at. When I got my saw it seemed like everything was set up and ready to go so I started using it without making any adjustments. Then I started increasing the weight (it was cutting very slow) and as a result the blade started falling off. Most often this mutilated the blade and made it unusable. After the third blade I realized I needed to take a closer look. I found what I thought was the problem and then confirmed this with other saw manufactures.
First, (as you said John) the blade tracking need to be set with the blade guides removed. Then when the guides are installed they should twist the blade along the center line without deflecting downward or to the left or right. Ideally the bearings in the guide should only contact the back of the blade while cutting although it needs to just barely kiss the bearing all the time. Very slight pressure is also fine.?
The problem on my saw was that the blade guides were deflecting the blade downward nearly 3/8". With the guides set correctly the saw would not cut deep enough. The cover near the top wheel hit the base. Even when I removed blade cover the upper frame hit the switch housing before completing the cut. After doing a little research I realized my saw was defective. I looked at two other older saws that did not have this issue. I suspect this problem is a result of a bad setup at the factory. Maybe the pivot point for the head was not located correctly. In reality the pivot point on my saw needs to be dropped over 1/4".?
I ended up putting a 1/4" steel plate under my vise. This elevating plate raises the stock enough so that the blade can complete the cut without being deflected significantly by the blade guides. Since making this change I can increase the downward pressure to full. Sometimes the saw stalls but the blade never comes off. In fact, I have had the same blade on my saw almost a year now. It has cut a LOT of steel.?
I had a bunch of these elevating plates made (laser cut) and have sold over 60 of them (apparently quite a few saws have this defect). I currently have one plate in stock but if there's enough interest I can have some more made. When the price of steel went nuts I raised the price from $29.50 to $39.50 but honestly it's barely worth my effort. After the cost of steel, laser cutting and shipping I'm about $2 ahead. Let me know if your saw needs this plate. If there is enough interest I'll have more made.?
Mark
https://markq6zlmc.fws.store/Elevating_Plate/p7671236_21023715.aspx
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Re: Blade tracking problem
Good to know something worked. Not proven yet that it IS your tracking problem until you try the new blade You said you cut mostly Aluminium. For this there is no point in using a bimetal blade. Bimetal blades are useful to cut steel on high speed? and at high bow weight where the cutting edge can get hot enough to dull a carbon steel blade but Al conducts heat so fast the edge never gets near the temp needed (5-600F).? ?Quickest and straightest cutting of bulk soft materials like Al is to use a 4 or 6 tpi blade and Carbon steel cuts just as fast as bimetal in soft stuff.? Do your wallet a favour and get a 4tpi blade for the 2"+thickness and an 8 or 10tpi blade for thinner stuff. The normal 10-14 bimetal blade as actually too fine for any aluminium other than thin section.? You never really want more than about 6 teeth in a cut in Al because the swarf sticks in the gullet of smaller teeth and either makes it cut vertically crooked, or jams the blade in the cut (stalling the motor and possibly burning it out) - jv
Today I was cutting a 3.25" diameter piece of aluminum on the bandsaw and keeping a close eye on it, to see if the "bobble" corresponded to the weld on the blade.? I noticed it was getting worse and worse so I turned the saw off immediately after the frame jumped, then examined the blade.? It has a crack extending almost halfway across the blade.? So John's comment was dead-on.
Time to get myself another blade or two.....
Mark
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Re: Blade tracking problem
Yes, lacutting products is one of the sources I found on Amazon and ebay.? Their bi-metal blades actually are slightly lower priced than Harbor Freight's bi-metal bandsaw blades.? There are a bunch of Chinese-made blades that are cheaper but I'll support a US-based company.
Thanks for the discount code!
Mark
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Re: Blade tracking problem
On 2/22/2022 6:11 PM, Mark Kimball wrote: Today I was cutting a 3.25" diameter piece of aluminum on the bandsaw and keeping a close eye on it, to see if the "bobble" corresponded to the weld on the blade.? I noticed it was getting worse and worse so I turned the saw off immediately after the frame jumped, then examined the blade.? It has a crack extending almost halfway across the blade.? So John's comment was dead-on.
Time to get myself another blade or two.....
Mark Check out the guys at lacuttingproducts.com . I've been buying their stuff for a while now , good products at a decent price . Get on their email list for some pretty decent discounts from time to time . I think MAGLA5 is still good for 5% . -- Snag My rights don't end where your fears begin.
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Re: Blade tracking problem
Today I was cutting a 3.25" diameter piece of aluminum on the bandsaw and keeping a close eye on it, to see if the "bobble" corresponded to the weld on the blade.? I noticed it was getting worse and worse so I turned the saw off immediately after the frame jumped, then examined the blade.? It has a crack extending almost halfway across the blade.? So John's comment was dead-on.
Time to get myself another blade or two.....
Mark
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Re: Duracraft 4x7 bandsaw
Alright now we're getting somewhere.? Duracraft name should have rung some bells, but my hearings not what it was!?
An early saw for sure, and US made I think? (though US firms were starting to outsource at that time).
Yes, they are cam follower bearings and still available from needle roller specialists like IKO (). Probably one eccentric- and the other concentric-mount.? IKO ones look to be dis-assemble-able but if yours are peened, then that is not possible. 4 new ones would probably cost more than you paid for the saw.?
Its unlikely that all have failed, you should try to save the good ones.? ?
Have you tried cleaning them in an ultrasonic bath and then re-introducing grease by dissolving it in a an evaporating solvent like petrol? What about washing out with WD40 or or a more active cleanser like CRC 2-26??
Relatively easy to retrofit modern bearing mounts, by filling in the large cam follower hole with a slug of mild steel glued in place with high strength red Loctite, or thread the hole and Loctite in a threaded slug, then tap or drill for the new bearing mounts.?
So long as the inner roller surface is in the same place on both upper and lower guide assemblies there will be no problem adjusting the saw for squareness. Minimum distance between the rollers should be 0.020" or less (blade is 0.025" thick).
HF, Jet and Grizzly all have spare parts, look for a saw that has different part numbers for the inside and outside roller mounts, so you get a concentric inner mount and eccentric outer (manuals in the Files section of the site).??
The simplest mount is the top-hat washer (concentric inner, eccentric outer) to mount the bearings on with spanner flats filed on the 'brim of the hat' to adjust the?eccentric ones, fixed to the bracket (the bit the bearings are mounted on) with a 1/4" or 5/16" cap screw through, but you need a lathe for that.
Metric bearing sizes 629, 6000, 6200 and 6201 have all been used as side guide rollers on saws, the higher numbers are bigger OD and will last longer. You could pick equivalent inch sizes too if you're making your own mounts - all std saws use metric bearings. - jv
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Re: Duracraft 4x7 bandsaw
??? ??? Make your wife fish for breakfast
??? animal
On 2/21/2022 4:19 AM, Joe Widmayer via
groups.io wrote:
toggle quoted message
Show quoted text
John,
It appears the horizontal bearings are cam followers and are not
supposed to be taken apart.
Not to hard to find for the regular one but the eccentric may be
expensive. I hoped to remove the eccentic on the shaft but it
looks like it was peened at the thin part to keep it on: and, or
may have been pressed on.? Not sure if it is removable without
destroying it.
Trying to figure out the eccentic on the shaft.? To my thinking,
it must not rotate on the shaft to make adjuctments possible.? So
it is pressed on or peened to keep it in place.? I could possibly
remove the peened part by grinding/filing.? No real way to press
it off that I can think of.
A couple of thoughts:
I too often try to do things too inexpensively.
Cam followers can be lubricated.? The person I bought the saw from
said he "cleaned it up a bit with PB Blaster"? That may have
remove the lubricant.
The saw is 43 years old.? The only wear items are those bearing.?
I should try to lubricate the cam followrs and replace the
vertical bearing.
I got the saw a few days ago.? It did not have a blade.? I should
have put a blade on it first thing.? My excuse was looking at
videos replacing bearings, not cam followers for $10.
I should go fishing or make my wife breakfast.? OK, I should do
both.
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Re: Duracraft 4x7 bandsaw
On 2/21/2022 6:19 AM, Joe Widmayer via groups.io wrote: John,
It appears the horizontal bearings are cam followers and are not supposed to be taken apart.
Not to hard to find for the regular one but the eccentric may be expensive. I hoped to remove the eccentic on the shaft but it looks like it was peened at the thin part to keep it on: and, or may have been pressed on.? Not sure if it is removable without destroying it. Yours are totally different from mine . Looking at your photos , I suspect the bearing is pressed onto the eccentric . If so , you won't get it off intact . A big c clamp , vise , or press with a sleeve pushing on the outer race should get them off . -- Snag My rights don't end where your fears begin.
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Re: Duracraft 4x7 bandsaw
John,
It appears the horizontal bearings are cam followers and are not supposed to be taken apart.
Not to hard to find for the regular one but the eccentric may be expensive. I hoped to remove the eccentic on the shaft but it looks like it was peened at the thin part to keep it on: and, or may have been pressed on.? Not sure if it is removable without destroying it.
Trying to figure out the eccentic on the shaft.? To my thinking, it must not rotate on the shaft to make adjuctments possible.? So it is pressed on or peened to keep it in place.? I could possibly remove the peened part by grinding/filing.? No real way to press it off that I can think of.
A couple of thoughts:
I too often try to do things too inexpensively.
Cam followers can be lubricated.? The person I bought the saw from said he "cleaned it up a bit with PB Blaster"? That may have remove the lubricant.
The saw is 43 years old.? The only wear items are those bearing.? I should try to lubricate the cam followrs and replace the vertical bearing.
I got the saw a few days ago.? It did not have a blade.? I should have put a blade on it first thing.? My excuse was looking at videos replacing bearings, not cam followers for $10.
I should go fishing or make my wife breakfast.? OK, I should do both.
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Re: Duracraft 4x7 bandsaw
Terry,
I think my saw has "cam followers" for the horizontal bearings.? There is not a clip.
They are not too hard to find except for the one with the eccentric.
Thanks,
Joe
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Re: Blade tracking problem
My blade might have upwards of 20 hours on it so a relatively simple thing to do is buy a new one and see how it behaves.? I do see the frame bob up & down but it _appears_ to be associated with the weld.? I'll see if I can mark that location to see if it correlates to the bobble.
I'm starting to understand that bandsaws have more components that affect their performance compared to your average (manual) lathe or mill.? They're overlooked because they usually are just used for the first step in machining something -- i.e., cut stock so it can be further processed by something else.? Fortunately they're not expected to be highly precise, but it IS a time-saver (and material-saver) if the cuts are reasonably accurate.
Mark
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Re: Blade tracking problem
Yep that iterative approach (loosen adjust re-tighten) is necessary, and yes the spring-bending of the frame can be used to set the tension - but there is the same old problem - you have to know what full tension IS before its any use.
Having a blade that you know tracks properly is a sort of given when adjusting tracking, like knowing how to adjust to full tension. Couple things to try: 1. Blades not welded square don't track truely?and would cause the problem you?describe. Probably something everyone should do first, when trying to solve tracking problems, is try a new blade. If it cures the problem you're ahead of the game, if not, you know it's?not the blade and you've?got a?good spare. 2. If the blade was cracked it would track away from the rim. You can test this out by cutting a piece of steel at full (8lb) bow weight - if the blade is cracked the head will bob up and down as the crack passes over the rear support rollers. Not well known, but the blades crack just by running them enough around the standard bandwheels - even without?guides twisting it, a blade will only last from?20-50hrs. Possibly yours is cracked???? I'll keep thinking - jv
John,
Following your suggestions, I loosened/removed the blade and zeroed the upper wheel, laying a straight edge across it to monitor the tilt as I adjusted the tracking mechanism.? Then I re-tensioned and adjusted until the blade was just above the rim flange.? The blade still was misaligned enough to scrape the guard.? I noticed that tightening the mechanism's center bolt also affected the tracking so I used an interative approach -- adjust the bottom screw, tighten the center screw, check the tracking, loosen it and re-adjust the bottom one, and so on.
FYI, I became curious about how much the frame itself is bending on that axis.? I didn't expect much, but what the heck.? I again used my laser pointer, attaching it to the top of the frame and aimed it down.? There is a lip near the bottom where I could place a machinist ruler to check the deflection.? From no-tension to fully tensioned, the beam deflection was pretty small -- something on the order of .02 inch, .5mm.? ?I just realized that this could be a way to set the blade tension.....with some characterization, anyway.
I also loosened up the blade guides and found that worsened the tracking problem.? Moving the bottom blade guide down also exacerbated the tracking problem.
Other than fooling around with the tracking mechanism and blade guides, I haven't modified the band saw.
The blade isn't the newest in the world, although it is NOT the one that came with the saw -- not long after getting the saw I got a bimetal blade for it.? If the problem is (somehow) related to the blade, would there be any other symptoms to look for?
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Re: Blade tracking problem
John,
Following your suggestions, I loosened/removed the blade and zeroed the upper wheel, laying a straight edge across it to monitor the tilt as I adjusted the tracking mechanism.? Then I re-tensioned and adjusted until the blade was just above the rim flange.? The blade still was misaligned enough to scrape the guard.? I noticed that tightening the mechanism's center bolt also affected the tracking so I used an interative approach -- adjust the bottom screw, tighten the center screw, check the tracking, loosen it and re-adjust the bottom one, and so on.
FYI, I became curious about how much the frame itself is bending on that axis.? I didn't expect much, but what the heck.? I again used my laser pointer, attaching it to the top of the frame and aimed it down.? There is a lip near the bottom where I could place a machinist ruler to check the deflection.? From no-tension to fully tensioned, the beam deflection was pretty small -- something on the order of .02 inch, .5mm.? ?I just realized that this could be a way to set the blade tension.....with some characterization, anyway.
I also loosened up the blade guides and found that worsened the tracking problem.? Moving the bottom blade guide down also exacerbated the tracking problem.
Other than fooling around with the tracking mechanism and blade guides, I haven't modified the band saw.
The blade isn't the newest in the world, although it is NOT the one that came with the saw -- not long after getting the saw I got a bimetal blade for it.? If the problem is (somehow) related to the blade, would there be any other symptoms to look for?
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Re: Blade tracking problem
Ahh... new information and old assumptions...?
If this only started when you increased the tension then it could be just a blade tracking problem, though teeth scraping the blade guard means the blade is riding pretty far out on the bottom wheel. The only way I can think that it would ride this far out when the tension?is increased, is if you've tilted the top wheel too much.
The blade tracking process is as follows (with apologies to John Pitkin, as it doesn't quite follow his instructions): Tracking on the top wheel is by tilting it, so the blade runs back toward the rim.? The wheel should only be tilted to get it to track close (<0.040") to, but just not touching, the rim,?no matter what happens to the tracking on the bottom rim.? Then the bottom wheel is moved in or out on the drive shaft to get it to also track <0.040" from its rim.? You do this by changing the length of the spacer between the bottom wheel and the gearbox out bearing.
If you've tilted the top wheel too much but not tensioned the blade enough, the blade can be made to run within 0.040", but then increasing the tension will drive the blade toward the top rim. This action actually bends the blade even more across its 1/2" width, which it resists; so the rest of the blade, which is also looped around the bottom wheel, wants to move outward and can scrape the blade?guard.??
Begin by de-tensioning the blade and removing all the tilt from the upper wheel tracking mechanism, then give the tilt screw 2 full turns inward. as the starting point for tracking.?? Re-tension the blade to full tension and fine tune the tracking to get it to just not touch the top wheel's rim
With any luck it will track properly?on the bottom rim now.? If not, then move the bottom wheel out until the blade tracks on the bottom rim too.? If it is so far out that the blade scrapes the guard still, then I can't?help but think?you'll have to change the bearings just to see if that is still the original problem?- jv ??
I've found that until you hit on the answer, increasing information about a problem sometimes leads to increasing confusion as well.? I think I'm in that part of the learning curve right now.? I performed John's recommended test for bandwheel deflection, but used a laser pointer + magnetic base attached to the bandwheel instead of a physical lever arm.? For an optical lever about 18 inches long I observed a little over 1/8" deflection as I tightened up the blade.? This suggests that the bearings are OK.
I also checked to see how gunked up the bandwheels were, and was pleasantly surprised to find that they were pretty clean.? I generally cut aluminum dry, and that's what I cut most often so there was little to no accumulation of swarf.
John's comment regarding the guides has me wondering if they have something to do with my problem so I will fool around with them to see what happens.
Something else I'm going to do is remove the blade and place a straight edge across the bandwheels to see how much offset there is between them.? I don't see how that could change over time (particularly if the bearings are OK) but, hey, maybe I'm not confused enough yet :)
Based on a previous extensive discussion regarding blade tension I started using higher blade tension and that roughly coincides with the time I noticed the tracking problem.? So who knows when it really began.
Mark
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Re: Blade tracking problem
I've found that until you hit on the answer, increasing information about a problem sometimes leads to increasing confusion as well.? I think I'm in that part of the learning curve right now.? I performed John's recommended test for bandwheel deflection, but used a laser pointer + magnetic base attached to the bandwheel instead of a physical lever arm.? For an optical lever about 18 inches long I observed a little over 1/8" deflection as I tightened up the blade.? This suggests that the bearings are OK.
I also checked to see how gunked up the bandwheels were, and was pleasantly surprised to find that they were pretty clean.? I generally cut aluminum dry, and that's what I cut most often so there was little to no accumulation of swarf.
John's comment regarding the guides has me wondering if they have something to do with my problem so I will fool around with them to see what happens.
Something else I'm going to do is remove the blade and place a straight edge across the bandwheels to see how much offset there is between them.? I don't see how that could change over time (particularly if the bearings are OK) but, hey, maybe I'm not confused enough yet :)
Based on a previous extensive discussion regarding blade tension I started using higher blade tension and that roughly coincides with the time I noticed the tracking problem.? So who knows when it really began.
Mark
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Re: Blade tracking problem
Though I don't understand the circumstances properly, it obviously?worked? for?you, Dave Generally, increasing tension makes the blade track away from the rims of both wheels because the tension takes out the play in bearings and bends/flexes the axles of the bandwheels. If you can make the band track on bandwheels without the guides in place, it will track with the guides in, as twisting the blade seems to make the blade track toward the rims - jv
On Sun, Feb 20, 2022 at 6:27 PM Dave Seiter < d.seiter@...> wrote:
I had a tracking problem for the past few years, and nothing I did helped (the blade I was using during that time developed a lot of cracks and finally broke).? After replacing it, I recalled someone saying that even if you thought the blade tension was good, it probably wan't.? Taking that to heart, I *really* tightened the blade, and the tracking is now great.
-Dave
On Saturday, February 19, 2022, 01:04:37 PM PST, John Vreede < vreededesign@...> wrote:
Hi Mark You won't necessarily see or feel any 'play' because the inner bearing is generally OK and holding it steady but you can make it readily apparent with an 18" strip of aluminum angle or wood to which you fix some small magnets and apply to the rim of bottom bandwheel
I removed the blade on my saw so I could mess with the drive wheel to see if there is a lot of play in it.? I didn't observe much, if any.? But I'm not sure how little it takes to cause a tracking problem.
Mark
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Mark
John Vreede
