Tensioning & Tracking Bandsaw Blade

[pollys13]

Hi all,
I have a Draper 16 inch 3 hp bandsaw it has flat tires and came from Draper fitted with a 1 inch wide blade 4 tpi.
The flutter method of setting the blade tensions seems very accurate. Though I wasn't very happy about having 10 inches of unprotected hook blade wizzing around. So I bought a Dakin Flathers tension gauge,which actually compared to other brands, was a quite reasonable price of £185.

I've backed off the side bearings and thrust bearings upper and lower and removed the throat plate.
The Flathers gauge instructions say, " Place the tension gauge on a slack blade, there should be........' just enough tension '....... to keep the blade on both wheels.

On the saw itself I released the quick release tension lever to fully release the tension. Put the gauge on the blade, but the weight of the gauge causes the blade to move down and the gauge is resting on the side of where the throat plate sits. I don't know if the gauge resting on the table like this alters the reading?
Anyway, I then zero the gauge and reapply the tension with the quick release lever I then got a reading of 20 psi and 24 psi at another try.
With the 20 psi reading. If I take the gauge off then back on and rezero the gauge then release the tension gauge I get a reading of 17 psi.

To try to set the bandsaw up correctly I'm referring to Lonnie Birds, " The Bandsaw Book ", as an authority. He says most blade manufacturers recommend 15,000 psi to 20,000 for a common carbon-steel blade. I have contacted Draper and chased them up, asking what the tension for their blade should be and the maximum tension the saws frame can take, bi-metal blades etc, so don't know if maximum tension frame can support comes into the equation?
I've found Draper support is almost non existent no reply, response on this from them.

I'm also refering to Mark Duginskes, " The new complete Guide To The Band Saw " Regarding tracking the blade, " A wide blade can be tracked close to the middle of the tire or with the teeth off the front of the tire. If the blade is coarse, ( as mentioned earlier the bandsaw has a 1 inch 4 tpi blade on it ) If the blade is coarse or has carbide or bi metal teeth, it is better to have the teeth run off the front edge of the tire so they don't damage the rubber material. "

I Googled and I understand 4 tpi is a coarse blade?
Should I track this blade with the teeth off the front edge of the blade? Also I'm thinking positioning the blade teeth and the blade guard might be too close, and if something..... bad happened, the blade might chew into the guard?
See attached,may make clearer my concern on this point.
Cheers.

 

[RobinBHM]

A 1" blade seems a very big blade for your machine. I suspect only industrial sized bandsaws with a massive frame would be able to fully tension such a big blade.

I dont agree with the advise of having the teeth over the front of the wheel. I think that advise applies to band resaws with 2" + blades

 

[pollys13]

A 1" blade seems a very big blade for your machine. I suspect only industrial sized bandsaws with a massive frame would be able to fully tension such a big blade.

I dont agree with the advise of having the teeth over the front of the wheel. I think that advise applies to band resaws with 2" + blades

" I dont agree with the advise of having the teeth over the front of the wheel. I think that advise applies to band resaws with 2" + blades "
Uum OK Robin, thanks. The 1" blade is what Draper supplied with the machine, so I assume the frame is strong enough to fully tension it properly. As I say no response from Draper about this.

 

[Alexam]

Hi Polly,
forgive me if I'm wrong, but it seems that you are new to bandsaws and setting them up.?
With a new bandsaw, the first thing to do is get a couple of smaller blades. The 1" blade will only be used when you are cutting large, heavy timber, but please say what are you intending to use your bandsaw for, as this will help others to help you?
Buying blades - Ian Black at Tuffsaw is about the best you can find and he is very helpful if you can manage to speak with him. Just telling him what you want to work on will enable him to guide you to the correct blades. I have several 1/2", a 3/8", 1/4" as the most useful, but 1/8" for tighter turns, but in general terms, manufacturers of bandsaws do not supply very good blades as you will find on this forum.

There have been many books and DVD's on how to set up a bandsaw correctly, some of them I tried when I started, but I now use a method that Alex Snodgrass uses when I am using smaller blades, which may not be best for large blades. The following may help
THE BEST FROM A BANDSAW 'Alex Snodgrass of Carter Industries has an excellent video https://www.youtube.com/watch?v=wGbZqWac0jU on a tune up method that works well, but if you want to get the best use of your bandsaw on an ongoing basis, then the Steve Maskery DVD's will show you far more and they are a real investment. http://www.workshopessentials.com/shop/

For checking the tension of your blade - A Flutter test Video's
https://www.youtube.com/watch?v=chyo9chuwJs
https://www.youtube.com/watch?v=z8zZuDosSy0

The most important thing to remember is 'take your time when setting up'. It needs to be right otherwise the work will suffer and you may get fed up with a machine that is there to help you.

Do ask lots of questions as the members here are all there to help. Good luck
Malcolm

P.S. You said that "On the saw itself I released the quick release tension lever to fully release the tension". Don't do that. The tension leaver needs to be in position correctly when using the saw. Do not run it with the tension leaver off.

 

[Steve Maskery]

Ditch the blade.
I don't think you will be able to tension a 1" blade on your machine. I don't care if Draper did supply it, the machine is not man enough for the job.
Imagine the blade as a rubber band. Two of them, identical apart from the width. Stretch them between your fingers. Which will be harder to stretch, the narrow one or the wide one? Bandsaw blades are the same. 1" is very wide, a lot of steel, to stretch.

And anyway, why do you need a 1" blade? You can cut quite happily with a 1/2" blade if it is set up properly.
I'm currently cutting 5" poplar with a 1/2" 3TPI blade, it's the coarsest I've got, but if I had a coarser one I'd use it.

 

[Phil Pascoe]

I ripped 7" ash with 1/2" 3 tpi taking it easy on a quite small bandsaw. (Woodstar sb12)

 

[Eric The Viking]

I don't think Alex Snodgrass is wrong, exactly, but he's probably not right for the majority of Chinese bandsaws of which Draper's is but one of many, similar designs. If you watch his trade-show videos, you'll see he demonstrates on bandsaws with cast iron or steel frames. These inherently have far less bend and springiness about them than the box-section style I think you (and I) have*.

Mine (SIP12") distorts significantly out of shape if you put a big blade on it and tension it fully. The "backbone" bends, the upper wheel moves towards the base, and the blade guard moves off line (it's no longer parallel to the 'natural' path of the blade).

For all but the smallest blades, I have to set up the guides for a specific guard height (material thickness), as, if set up centrally, they're closer to the path of the blade at the top than the bottom. It is a pain to do, and I sometimes forget this in a rush whilst doing some odd job, then curse as my one bit of stock is messed up by it not cutting straight. Conversely, if I have a batch of stuff to do, for example resawing for a frame or legs of something, and I make the effort, the thing delivers very good results (Tuffsaws blades help enormously too).

Draper's lack of customer support notwithstanding, they can't tell you what the right tension ought to be, simply because they don't know. It depends on the blade and all the other circumstances - the stock thickness, the nature of the material itself (what it is, e.g. Oak or deal, and how the grain runs.,etc.), whether you're resawing or cutting curves, and so on. Even if your tension-measuring tool works correctly, all you can really do is establish consistency of tension, but that won't necessarily help, as nominally identical blades will differ once they've been used and the teeth wear, the steel is stretched, etc.

The wheels have a crown (camber), like a road, but the crown's purpose is to keep the blade in place. The teeth of the blade have a set, so they stick out sideways slightly. There's no advantage to the teeth being off or on the wheel, except this: If the teeth are close to the top of the crown of the wheel, they'll dig into the tyre. This has three consequences:

• They'll cut into the tyre and potentially damage it.
• The tyre will tend to deform the blade's set - teeth set to the left will be squashed, but teeth set to the right won't be (if it's normal orientation with the support pillar and wheels to your left as you push the stock). Depending on tooth pattern, hardening, etc, this may lead to permanent asymmetry, which means that blade will (always) drift.
• The teeth themselves will force a twist into the blade, turning it slightly anti-clockwise as you look down on the table. This you can correct for, but it's not helpful.

So I track my blades so that the teeth of the bigger ones are just touching the tyre but not digging into it. The teeth do come very close to the front of the wheel. It helps the blade to stay parallel to the mitre track. The fence tracking on mine is pretty crude (you skew the clamping rail), so it's less hassle to get it running as straight as poss to start with!

Steve M. has a good tracking-adjustable fence design on his bandsaw DVD, incidentally.

With smaller blades the teeth digging in is unavoidable, so I go for a compromise such that the blade is just off the centre of the crown towards the front, not much at all, but it to eases the digging-in effect. In any case, the teeth are a lot smaller, and the distance they stick out is a lot less, and I'll be cutting curves with them, so the overall nuisance value is minimal.

The other advantage of this is down at the roller guides: They're simply sealed ball bearings, 8mm thick. That's way too deep for a small blade - you really don't want the guides running on the teeth. If the blade is slightly forward, I have more adjustment possible on the guides, so that I can set the side ones to run behind the teeth (only using half their thickness or less), still have good thrust support from the back roller, and it all runs nicely.

As for actual tension: Is it running quietly; am I getting consistency and straight cuts; how much can I deflect the blade on the back length between the wheels by twisting it with finger and thumb? I don't take much notice of the "tension indicator" - it measures blade length! And crudely, at that. Your posh one probably does it correctly, but as I said, I'm unconvinced that tension on its own tells me much.

It all works. I get good clean cuts, and don't seem to wear through tyres too fast.

E.

*My frame is basically a single steel box section stupidly weakened significantly by the hole for the NVR switch (idiots!), yours seems to be a pair welded side-by side, which should be more rigid, although it will still bend a lot if you're trying to tension 1" blades!

 

[Steve Maskery]

Steve M. has a good tracking-adjustable fence design on his bandsaw DVD, incidentally.

Well thank you for the plug, Eric, but it's not quite true

I do have a fine adjuster fence on my Bandsaw Essentials DVD but it's designed to adjust the distance to the blade finely, not the tracking. I can move the fence accurately and precisely, to 0.1mm. I only adjust the tracking using the, er, tracking adjuster knob. The fence stays parallel to the mitre slot. This way, not only do I rip straight, but I can use use the mitre fence for tenon shoulders, for example, or run jigs in the sot, knowing that my cut will be true for that operation, too. If I used the fence to compensate for drift, then the mitre slot would be useless.

Incidentally, in the Snodgrass video he doesn't get the tracking quite right. When he does his test cut, he has to stop and adjust the saw. He doesn't skew the fence, but he moves the whole table round. He glosses over it because he is an excellent showman, but you can see him do it. That is easy on his BS because of its design, but you couldn't do that on any BS that I have seen, it would take a spanner and ten minutes. The only way anyone should adjust the tracking is with the tracking adjuster.

Polly: You and SunnyBob should get together!

 

[Alexam]

Eric makes a good point that I missed and that is the wider blades 3/4" and 1" are wider that the top wheel if the teeth are in the centre of the wheel. Dont try and centre the thickjer blades if you still intend to use them. Steve Maskery's DVD will show you another way, but for the smaller blades, the the Alex Snodgrass method works well for me and many others. You need to find what you are comfortable with.

Malcolm

 

[Eric The Viking]

Steve M. has a good tracking-adjustable fence design on his bandsaw DVD, incidentally.

Well thank you for the plug, Eric, but it's not quite true
I do have a fine adjuster fence on my Bandsaw Essentials DVD but it's designed to adjust the distance to the blade finely, not the tracking.

I sit corrected (happens a lot )

Of course if I'd actually got round to making Steve's adjuster, etc, I'd know that.

TBH, I follow Steve's method and the drift on my saw is almost nothing (once I HAVE set it up properly, that is). I rarely have need of really fine adjustment (nor to skew the fence).

 

[pollys13]

Steve,
Yes, I'm pretty certain now I'll junk the blade, don't want to risk damaging the bandsaw and from what people have advised, using a better blade will get a much better quality of cut. A lot of people here have spoken very highly of Tuffsaw. When people first mentioned Tuffsaws to me I did have a quick look at the site, I'll have another look. Regarding what I want to do with the bandsaw see my reply to Malcolm.
Cheers.

 

[pollys13]

Eric thanks for the input, the tires on the saw are flat.

 

[pollys13]

Malcolm,
We have the Wiltshire Wildlife Trust here, I regularly visit their sites. I would also be using the bandsaw for making my replacement wedged tenon house doors and also other house doors in the future.

 

[Steve Maskery]

the tires on the saw are flat.

You should still be able to track properly using the tracking knob. Although the tryes my be flat, because the top wheel is tilted backwards or forwards a bit, the shape where the blade runs will be just the same, pretty much, as if the tyre were crowned. The top of the wheel moves in an arc, doesn't it, as you alter the tensioner. That arc is the equivalent of the crown as far as function is concerned.

 

[pollys13]

the tires on the saw are flat.

You should still be able to track properly using the tracking knob. Although the tryes my be flat, because the top wheel is tilted backwards or forwards a bit, the shape where the blade runs will be just the same, pretty much, as if the tyre were crowned. The top of the wheel moves in an arc, doesn't it, as you alter the tensioner. That arc is the equivalent of the crown as far as function is concerned.

Ah OK Steve, cheers.

 

[pollys13]

Off to look at Tuffsaws site now..... stay tuned

 

[Steve Maskery]

If you want to cut tenons, you do need to have it spot on. I recently made some new doors for my workshop. I chose to cut them on my tablesaw, but I had to do some handwork to finish them off.
If I could have been bothered to set my saw up properly beforehand, I could have cut them on my BS and saved myself some time. I have a jig for the BS that works in the same way as my jig for my TS. But I was too lazy to do that. Instead I fettled my BS afterwards (it's a job I'd been putting off ever since it came out of storage). Talk about putting the cart before the horse.
Right now it is cutting very sweetly and is a pleasure to use.

 

[pollys13]

Malcolm,
I did post quite a long reply to you but doesn't seem to have appeared on the board. Yes I am relatively new to bandsaws. I have the two books I mentioned. You did mention the Snodgrass video in a previous post and I did look watch it. I've also downloaded several YouTubes on tracking and tensioning the bandsaw but not much wiser. I'd be using the bandsaw initially for resawing Lime to practice my woodcarving. Resawing is economical use of the Lime. Especially for practicing lettering, as might go down say 3/8". So when done the lettering can resaw it off then perhaps through the planer and start over. I have several 4.2M x 100mm x 50mm Lime boards I'll be using to practice lettering and relief carving. Relief carving I might use a 1" thick board, lower the ground around the relief about 1/2". When done carving, can resaw it of. Then use the 1/2" board left to do more lettering and so on. Also when I got some additional carving tools. G&S Timber had a special promotion I got two nice big blocks of 250mm x 250mm x 100mm Lime for free. So will need to resaw those or use for carving in the round.
People have given me pieces of other species, Sapele, Ash, Sycamore, Fruit woods, Poplar, quite a lot of that and some quite large pieces of Oak. All of which will be used for carving. I also have an Axy Hobby Woodturning lathe, so at some stage I will be cutting out blanks. A carving, turning friend gave me some great chunks of Elm from trees he cut on his property, chopped them up with his chainsaw, for me to use for turning bowls when I'm ready.

I would never run a bandsaw untensioned. I do know of the flutter method but would be very uncomfortable having 10" of exposed blade running round. Mainly why I bought the tension gauge. One of my mottos, better safe than.... sorry
Cheers, Malcolm.

 

[Beau]

A 1" blade seems a very big blade for your machine. I suspect only industrial sized bandsaws with a massive frame would be able to fully tension such a big blade.

I dont agree with the advise of having the teeth over the front of the wheel. I think that advise applies to band resaws with 2" + blades

It does seem like a big blade but it might manage it. I had Kity 613 that came with a 3/4 inc blade and it was great with it. Just seems a shame not to be able to use the blade you have especially if wanting to re-saw when a deep blade is ideal. As for teeth not overhanging the front again the Kity stated that's exactly how it should be https://www.flickr.com/photos/mercian/9 ... 064650720/