Where am i going wrong with bandsaw?

[Fitzroy]

There's a video on YT with the video description is below. Looks like it could be related to your issue. This is also a Sabre 450 bandsaw.

"When trying to mount an original Record Power 3/4" (19 mm) blade the tension system all the way up still wasn't enough the have enough tension on the blade. By contacting Record Power the factory adjustment was pointed out as the option to still have the blade properly mounted. In this video it is explained and demonstrated how this can be done.Bandsaw: Record Power Sabre 450Blade: Record Power 3/4" (19mm), 3 TPI, L=3885mm, t=0.8mm"

 

[dvddvd]

Hi thanks I will have a look tomorrow

 

[Orraloon]

There's a video on YT with the video description is below. Looks like it could be related to your issue. This is also a Sabre 450 bandsaw.

"When trying to mount an original Record Power 3/4" (19 mm) blade the tension system all the way up still wasn't enough the have enough tension on the blade. By contacting Record Power the factory adjustment was pointed out as the option to still have the blade properly mounted. In this video it is explained and demonstrated how this can be done.Bandsaw: Record Power Sabre 450Blade: Record Power 3/4" (19mm), 3 TPI, L=3885mm, t=0.8mm"

Kinda wonder what Record were thinking about with the factory setting being too short for the specified blade length.
Regards
John

 

[Mike Fletcher]

Make sure the blade guides are set up with the back of the blade touching the thrust bearing. Keep the guide bearings off the teeth of the blade. Don't force the wood through the blade, let the blade do the work, as they say. And, has your piece of wood been put through the planner to ensure a square edge between the table and the fence. Obviously, is the fence square to the table and blade.

 

[AndyMc]

I also have the Sabre 450 but don't have the same problems with veneers. I was using a Tuffsaw Sabrecut (3/4 inch 3 tpi) blade which made short work of ~300mm apple trunks, although the cut quality was a little rough and needed cleaning up afterwards. Your blades are the correct size for the 450 (3886mm) so tension seems a good place to focus. The YT video @Fitzroy posted earlier is a good watch. Note the alignment of the teeth on the apex of the wheel - this is also recommended in the Snodgrass videos and should ensure the teeth of the blade are the least likely part to wander. You can also see how much slack he has in the blade before tensioning - way too much.

 

[recipio]

All good tips above especially having the blade run on the rear bearing. As a last resort clean the blade by holding a chisel while the blade is running ( avoiding the teeth obviously ) and also use one of those lubricant sticks - they make a surprising difference.

 

[Delaney]

I do not follow the snodgrasse technique.
Manufacturers suggest (depending on wheel thickness) that the back of the blade be offset by 2mm minimum from the centre of the wheel.
Draw a couple of reference lines on your top wheel to mark the centre (the apex of the crown). Then track the back of the blade, to the right of that line, by a min of 2mm.
This will end up putting the tension in the centre of the blade body.

In my veneer cutting experience, which is all I do, on hardwoods 250mm to 270mm, blade tension is really important. The blade between the centre of two wheels is at its most flexible.
I have found that unless you use the guides on the blade, it’s very difficult to get a straight cut and even then, straight means ‘acceptable’.
Putting the guides on the blade helps do just that. It helps keep the blade straight and stops it from deflecting as much.
if your veneer is thicker at the bottom (which is common), it is either an alignment issue, or the fact that the blade is at it’s most deflected, nearer the table.
If you think about the blade always being weakest in the middle and you’ve brought the top guide down to the top of the wood (150mm) the centre of the blade is now around the table height and so is being twisted (deflected) around that area.

Also note that the first cut you make should always be scrap (so to speak)). It then gives you a reference face and shows you how the blade will cut again. The blade will always cut/deflect the same way (generally).

I avoid the American way of veneer cutting, which means using the fence as your guide. This traps the blade between the wood and the fence. It is better imo, to make a sliding table and affix the wood to a sliding fence, cutting from the opposite side, so the wood is free to peel away as you cut.
You can make one relatively simply using ply/mdf. There are some tutorials online.
If you use the fence, I would try the blade on the opposite side of the block. I can’t say in physics with this way is better. It may not be; It’s my preference.

So:

Blade tensioned to max (not of spring but of blade). Max is likely always more than you think

Buy a slightly shorter blade to get more tension. Tuff offer custom lengths. Email the guy, he will help advise you.

Put roller bearings on blade. Check blade heat, otherwise no issues. Heat is what can damage the blade. Friction causes it but roller bearings turn with the blade so should be fine.

 

[BentonTool]

Thanks, it won't let me tighten it anymore, but not sure if it's tensioned enough? Seems to work if I drop the adjustable guides so only 50mm of blade is showing but put them up so 100mm of blade is showing and it starts to drift

If you take apart the blade tensioning mechanism, identify the compression spring, and take it to a local hardware supplier (such as those that supply machine shops) or go online to find a spring with more compression strength. These are typically what are referred-to as "die springs". Below is the link to McMaster-Carr, a reputable supplier in the colonies. I am sure you can find one locally.
https://www.mcmaster.com/products/die-springs/metric-color-coded-die-springs/

ADDITIONALLY, below are the directions from TIMBER WOLF, the company that manufactures the blades that I use. They have a novel technique for blade tensioning.

Blade Tension

Timber Wolf® Silicon steel blades are very stable at low tension or lower tension than what is normally recommended by most saw manufacturers and other blade manufacturers. By using less tension you will prolong blade life, consume approximately 20% less horsepower and increase the life of your wheel shafts and bearings. If a specific cutting application requires that more tension be applied to the blade, such as when resawing large material or cutting green logs, the recommended force for these blades can be increased by as much as 20%. To apply the exact same blade tension each time saws would require a very expensive hydraulic or air strain tensioning system to create a repeatable tensioning method. These systems would make saws cost prohibitive for most consumers as are the high quality tension gauges such as the Lenox® and Starrett® brands which can also give us a repeatable method for applying tension. The so called “deflection” method for tensioning, measuring the lateral defection of a blade, is more Kentucky windage than anything. In order to use deflection as a measure of applied force we would have to calibrate every steel type, blade width and blade thickness for every size saw and then create a tool to precisely measure the lateral deflection of the blade which is not practical. If you happen to own a high quality tension/strain gauge, below is a list of recommended psi for each width of Timber Wolf Silicon steel blade. If you do not own a tension gauge please see the “Flutter Test” method below this list:

Width Minimum/Maximum tension 1/8" = 7,000/10,000 psi 3/16" = 7,500/10,500 1/4" = 8,000/11,000 3/8" = 9,000/12,000 3/8" x .032 = 11,000/14,000 1/2" = 10,000/13,000 1/2" x .032 = 12,000/15,000 3/4" x .025 = 11,000/14,000 3/4" = 13,000/16,000 1" = 14,000/17,000

THE “FLUTTER TEST” FOR PROPER SILICON STEEL BLADE TENSIONING

This tensioning method is a guideline and should be used whenever possible. By using less tension you will prolong blade life, consume approximately 20% less horsepower and increase the life of your wheel shafts and bearings. If a specific cutting application requires that more tension be applied to the blade, such as resawing large material or cutting extremely large diameter logs, the determined force can be increased by as much as 20%.

​ A. BAND SAWS WITH TURN-SCREW SPRING TENSIONERS: Note: You will not be cutting any wood during this test. Also, your band saw tires and wheels must be in good working order. This test will not provide you with useful results if performed on a saw with damaged, cracked or flattened band saw wheel tires/band mill pulley v-belts.​ Remove the upper and lower band saw guides (the band saw blade body cannot be restricted on either side) and remove the table insert on your saw if equipped. Mount and track a blade on the wheels as recommended by the band saw/band mill manufacturer. Close all covers on the saw. Apply the recommended tension for the specific width of blade as per the band saw/band mill manufacturer. Start the motor or engine on your saw and bring the blade to full cutting speed. Allow the blade to run for approximately 30 seconds. Once you are satisfied that the blade is stable on the band saw wheels at full speed, very slowly reduce the tension on the blade while watching the blade between the wheels. As you slowly reduce tension on the blade you will see the blade start to move laterally on a vertical saw/mill and vertically on a horizontal saw/mill. Reduce tension until you see the blade develop a constant, not intermittent, flutter between the wheels. The amount of flutter will vary depending on the size of the saw and blade you are using, i.e., a ?” blade running on a vertical saw will move approximately 3/16” from side to side whereas an 1 1/4” blade running on a horizontal band mill will move 3/4” up and down. Once you achieve the appropriate amount of flutter for a specific blade you have reached what we call “zero”. At this point slowly increase the tension on the blade until the flutter is reduced to about 1/16 of an inch. Shut the motor or engine off and wait until the blade comes to a full stop. Add another 10% of tension to the blade by turning the screw-tensioner approximately 1/8 to 1/4 turn. The “flutter test” is now complete and you are now at appropriate tension for that particular blade. If equipped, make note of where the tension indicator is on the scale at this time or measure the compression of the spring in your tensioning mechanism. Re-install your band saw guides and if equipped re-install your table insert. Saws that use a pressure band saw guide will require you to release tension on the blade before re-installing the guides. If necessary, re-track and re-tension the same blade to the desired tension. You are ready to saw. ​ NOTE: All band saw blades will grow by a few thousandths of an inch in length within the first few minutes of sawing due to heat/thermal expansion. If you notice degradation in cut quality increase the tension on your blade by 5%.