Well, as the old saying goes... we do it right because we do it twice! Good job on the mill. I bet it is nice to have it working the way you want it again.
thanks for sharing I've been thinking I need to put a spring on my mill also . Since I changed the blade guides out I am cutting straighter boards in certain Logs but some are still wavy
Excellent video. Love that you go through the calculations. I have a commercial mill, no spring on the tensioner, just a simple cam. However the steel wheels have a drive belt between the steel wheel and the blade. It looks like your wheels are crowned and have a direct steel to steel interface with the blade. I wonder if the belt "cushion" provides some elasticity in the tension.
Did you make up a chart of blade tension vs elongation vs temperature? You could check the blade temperature as you go along and know what's happening to the blade length etc. Use a non-contact IR digital thermometer for reading the blade temperature. Oak must be considerably harder than walnut. And it is.
Hi there, great video. I have a DIY mill with a simple bolt tension but I am going to add a spring. I followed the link to where you bought it. I want to make sure I get the same spring rate. Was yours the 4,000 lb in one? Just confirming before I hit the go button. Thanks again!
I had bought two of these G5112161 Item Die Spring,XHD,2x2-1/2 In. From Zoro. But depending on your setup, blade, etc- you may need something slightly different.
It did droo quite a bit as I recall. Although, somewhat difficult to use as a reference because of extra tension coming from the dipping and diving once things went bad.
Basically from over the top. There are three flat bars on the top which help tie everything together. I just have to loosen the nut on those and swing them out of the way. Otherwise it's a clear installation. Looks like it would not be possible on camera, but actually is easy.
For me it is somewhere in the neighborhood of 3500 to 4000 LBS force (not to be confused with PSI). That is for my specific blade. What you want to do is measure the strain (amount the blade elongates) and based on Young's modulus of approximately 29,000,000 psi apply tension till you at around 30,000 to 35,000 psi. Take a look at these other videos. ua-cam.com/video/_5HeE_b7IMg/v-deo.html ua-cam.com/video/hhQ551aGaHQ/v-deo.html ua-cam.com/video/BwQSfKTTBZg/v-deo.html You could get a Band Saw Blade Tension meter for about $300-500, but my cheap version shown on the one video will do the trick. Just need to use math 😎. Good Luck.
If you had car tires for the drive wheels, would it be enough of a “spring” tension depending on the air pressure in the tires?.... With smaller wheels and shorter blades
Just from my ignorant view of material stress, cheap steel beams have limits of 32KPSI, better construction steel can get to 60KPSI. So wood band blades steel is high carbon, probably 120KPSI or better. But the weld is unknown properties as it's annealed, and probably not to perfect conditions by the manufacture. So 30KPSI is probably a good place so you don't cause premature failure. Just my guess from a strength of materials class 40 years ago, and I didn't work as a structural sort, as it was just a side class for my EE studies. I'm still playing with my harbor freight bandmill, and holding the log steady is still my problem. I tore the engine off, and put a 5HP 3phase motor, and using a VFD to power it. As I have it in the shop and don't like exhaust in my lungs or the sound.
Great fix! Amazing how much affect that had on the blade between the walnut and the oak!
I was certainly surprised at the difference also..
Well, as the old saying goes... we do it right because we do it twice! Good job on the mill. I bet it is nice to have it working the way you want it again.
Absolutely!
Dad's saying to me was "you can do it right or do it again". I usually done it again and again.
Welcome to the fold bro.@@misterp158
thanks for sharing I've been thinking I need to put a spring on my mill also . Since I changed the blade guides out I am cutting straighter boards in certain Logs but some are still wavy
I forget, what kind of wheels do you have?
Excellent video. Love that you go through the calculations. I have a commercial mill, no spring on the tensioner, just a simple cam. However the steel wheels have a drive belt between the steel wheel and the blade. It looks like your wheels are crowned and have a direct steel to steel interface with the blade. I wonder if the belt "cushion" provides some elasticity in the tension.
Thanks. Would imagine belt provides a small amount of "spring"..
@@ThoenWorks i am making also sawmill with diy steel wheels. What if i put hydraulic accumulator in hydrailic line or little spring pump ?
I think that would work.
Did you make up a chart of blade tension vs elongation vs temperature? You could check the blade temperature as you go along and know what's happening to the blade length etc. Use a non-contact IR digital thermometer for reading the blade temperature. Oak must be considerably harder than walnut. And it is.
I do not have an IR thermometer unfortunately. Certainly seems like oak generated more heat than walnut.. good this is the problem is fixed now. 😀
Hi there, great video. I have a DIY mill with a simple bolt tension but I am going to add a spring. I followed the link to where you bought it. I want to make sure I get the same spring rate. Was yours the 4,000 lb in one?
Just confirming before I hit the go button. Thanks again!
I had bought two of these G5112161
Item
Die Spring,XHD,2x2-1/2 In. From Zoro. But depending on your setup, blade, etc- you may need something slightly different.
On some cheap mills they get away without springs just by having a lightweight carriage, thing bows when you stick tension on them :D
Makes sense..
Are you not running a constant pressure on your Hyd. cinders that stretch your blades?
As the blade heats/expands are you seeing the pressure on the gauge change if so how much ?
It did droo quite a bit as I recall. Although, somewhat difficult to use as a reference because of extra tension coming from the dipping and diving once things went bad.
Why is you cage Bucking and Binding side to side when coming down the rails, at Lease thats what it looked like it was doing.
Q” How do you install your band saw blade .
Basically from over the top. There are three flat bars on the top which help tie everything together. I just have to loosen the nut on those and swing them out of the way. Otherwise it's a clear installation. Looks like it would not be possible on camera, but actually is easy.
How many pounds of force to tension your blade correctly? I’m building a mill and I am considering using a airbag to tension it.
For me it is somewhere in the neighborhood of 3500 to 4000 LBS force (not to be confused with PSI). That is for my specific blade. What you want to do is measure the strain (amount the blade elongates) and based on Young's modulus of approximately 29,000,000 psi apply tension till you at around 30,000 to 35,000 psi. Take a look at these other videos. ua-cam.com/video/_5HeE_b7IMg/v-deo.html ua-cam.com/video/hhQ551aGaHQ/v-deo.html ua-cam.com/video/BwQSfKTTBZg/v-deo.html You could get a Band Saw Blade Tension meter for about $300-500, but my cheap version shown on the one video will do the trick. Just need to use math 😎. Good Luck.
@@ThoenWorks looks like with a 10” airbag I can a achieve 7000 lbs of force plus.
If you had car tires for the drive wheels, would it be enough of a “spring” tension depending on the air pressure in the tires?....
With smaller wheels and shorter blades
Rubber tires will give you the "spring", but depending on the tire you may not get to the same tension in the first place.
Great video, where did you acquire the springs?
Springs were purchased form Zoro. I put details in description.
@@ThoenWorks thank you
Just from my ignorant view of material stress, cheap steel beams have limits of 32KPSI, better construction steel can get to 60KPSI. So wood band blades steel is high carbon, probably 120KPSI or better. But the weld is unknown properties as it's annealed, and probably not to perfect conditions by the manufacture. So 30KPSI is probably a good place so you don't cause premature failure. Just my guess from a strength of materials class 40 years ago, and I didn't work as a structural sort, as it was just a side class for my EE studies.
I'm still playing with my harbor freight bandmill, and holding the log steady is still my problem. I tore the engine off, and put a 5HP 3phase motor, and using a VFD to power it. As I have it in the shop and don't like exhaust in my lungs or the sound.
Going 3phase seems like a good thing. I didnt do that because I got this engine "cheap', but all electric seems like the way to go.
What PSI springs did you use? Part or Item number would be great. Thanks!
Zoro Item number G5112161 Die Spring,XHD,2x2-1/2 In www.zoro.com/raymond-die-spring-xhd-2x2-12-in-106810/i/G5112161/?q=G5112161
@@ThoenWorks Thank you very much!
Spring rating, source? TY
See in the description.
where you get the spring at.
From zoro.com.
Music adds NOTHING to ANY video ever. It just makes it hard to hear what you are saying.
Try soap
I've run soap in the past.