Bandsaw Blade Tension

[pollys13]

I have a Draper BS400P 400mm 2200w bandsaw.

The bandsaw is new and has flat tyres came with a 1" 4 tpi blade. Have contacted Draper no response had same trouble when contacted before on something else.

I've read in the Mark Duginske Bandsaw book that a coarse blade ( 4 tpi ? ) the teeth should be tracked over the edge of the tyre to prevent damaging the tyre.
At the moment blade is in the center of the tyre.

This is what I asked Drapers technical support, perhaps some members can clarify about what I've asked?

" In the owners manual Page 17 section 9.8 Setting up the blade tension. " The blade is at the correct tension if it can be moved approximatley 10mm sideways. " I assume I back of the upper and lower guide blades before doing this?
Section 9.8 goes on to say, " Tension the blade until the tension reading corresponds to the width blade you are using through the tension indicator window. "
See attached photo, the tension scale increments are not clearly visible. At what mark do I set the indicator to correctly set the tension for the blade that came with the bandsaw?
In the manual, page 19 section 9.11 Thrust bearing adjustment. " The large thrust bearing at the back of the blade, 3mm behind blade. ( typo error ? ) Are the upper and lower thrust bearings to be set 3mm behind the blade that came with this bandsaw?
You say the blade that came with the saw is 4 tpi I understand this is a coarse blade. I have read that with a coarse blade I should track the blade so the teeth are to the side of the tyre to avoid possibly damaging the tyre. What does Draper technical support say about this?
Thanks. "

Cheers everyone.
"all men dream: but not equally. Those who dream by night....wake in the day to find that it was vanity; but the dreamers of the day are dangerous men, for they may act their dream with open eyes, to make it possible."
T.E. Lawrence

 

[Beau]

All I can say is my old Kity had flat tyres and it's instructions recommended running the teeth just over the front of the tyre for all blades. I did and it worked very well.

This is how I was taught to set up a bandsaw blade.

Back off all guides and a thrust bearings. Set tension if you doubt the gauge sure there means to check for deflection over a certain distance but cant remember detail but sure someone will add this. Adjust tracking to were you want the blade to run on the wheels by manually turning the wheels and adjusting the tracking. Now set up the side guides close to the blade and bring the thrust bearing to within a whisker of the back of blade. IMO 3mm is a big gap.

 

[pollys13]

All I can say is my old Kity had flat tyres and it's instructions recommended running the teeth just over the front of the tyre for all blades. I did and it worked very well.

This is how I was taught to set up a bandsaw blade.

Back off all guides and a thrust bearings. Set tension if you doubt the gauge sure there means to check for deflection over a certain distance but cant remember detail but sure someone will add this. Adjust tracking to were you want the blade to run on the wheels by manually turning the wheels and adjusting the tracking. Now set up the side guides close to the blade and bring the thrust bearing to within a whisker of the back of blade. IMO 3mm is a big gap.

IMO 3mm is a big gap, uum I was thinking that too, Duginske says a cats whisker too.
Thanks.

 

[Alexam]

Tensioning the blade of a bandsaw. This may help
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

Malcolm

 

[Steve Maskery]

There is a lot of nonsense talked about BS tracking, much of it in User Manuals! I'm quite convinced that User Manuals are simply copied time and again. I wonder when someone who knows what they are talking about last sat down and wrote a manual from scratch.

I have asked several manufacturers why they recommend positioning the teeth off the wheel. Not one of them could give me an explanation. It's just always been like that.

What matters is that the blade tracks properly. That means that when you push the wood forward, the blade stays on the line, not drifting towards or away from the fence. In most cases that will entail the teeth of the blade being somewhere in the centre of the tyre. For a 1" blade that is not really possible, as not many bandsaws have wheels that are 2" wide... Yes, the teeth will put (a bit) more wear on the tyre, but tracking is more important.

I guess that Draper model is a big beast, it would have to be in order to tension a 1" blade. My Scheppach has wheels which will take a 1" blade, but I'm pretty sure that I could not satisfactorily tension such a blade, unless it was very thin indeed.

My advice would be to set the fence parallel to the mitre slot, then track the blade so that it cuts True North, and completely disregard where it rides on the tyre.

As for tension, the marks are just a guide. A 1" blade will be at the top end of the machine's capabilities, but it's not possible to say where exactly the gauge should read, as it depends on the thickness as well. You will know when it is right by the sound it makes.

As for the thrust bearing, it should be kissing the blade when you are not feeding the wood. It should not start to spin until you do start to feed, but there should be minimal movement of the blade backwards to make it do so. 3mm is a chasm.

If you have my DVD, watch the section on machine setup again, it explains exactly how you should do it, as well understanding how the blade position affects tracking. You should be able to rip AND CROSSCUT USING THE MITRE FENCE without drift.

 

[Ttrees]

Hello
I'd recommend you don't bother trying to tension a 1" blade on a saw that size
as it probably would damage the blade tensioning spring or threadbar despite what the
label says .I would not try a 1" even with thin blades .
Id start with a 1/2" experiment and then make your own decision.
Good luck.
Interesting ,I thought pretty much all these smaller saws had a crowned top wheel at least .
Thanks

 

[Beau]

yre.


My advice would be to set the fence parallel to the mitre slot, then track the blade so that it cuts True North, and completely disregard where it rides on the tyre.

This is poor advice IMO. It may work fine for 5 mins but once you have cut a few curves the teeth often get worn unevenly so what was briefly perfect now needs re adjusting. It's a nuisance but a reality of bandsaw use.

Bandsaw blades change throughout their life and if you need to accurately work from a fence I would always recommend reseting the fence to fit the blade before commence precise work.

 

[MikeJhn]

pollys13

Surprised Malcolm did not post this link: https://www.youtube.com/watch?v=wGbZqWac0jU I set my recently acquired BS350S in accordance with the instructions on the video and its been working superbly ever since, my thanks to Malcolm who directed me to it in the fist instance.

Mike

 

[Steve Maskery]

Well we shall have to disagree. Adjusting the fence to compensate for drift is a very second-rate solution. Sure, it's quick and easy, but you lose all functionality of the mitre fence if the rip fence is not parallel to the mitre slot. If the blade starts to run out, and I agree that that happens, then the fix is not to change the fence, but to adjust the tracking of the blade on the wheel. That's exactly what the tracking wheel is for!

 

[pollys13]

OK thanks everyone.

 

[Alexam]

pollys13

Surprised Malcolm did not post this link: https://www.youtube.com/watch?v=wGbZqWac0jU I set my recently acquired BS350S in accordance with the instructions on the video and its been working superbly ever since, my thanks to Malcolm who directed me to it in the fist instance.

Mike

I didnt include the bandsaw tuning by Alex Snodgrass that I use as the OP was asking about tensioning only. It is a tuning method that I continue to use and it works every time.

Malcolm