Thread: Horizontal Bandsaw 101 (BS-5S)

Earlier this week I purchased a BS-5S Horizontal Bandsaw as recommended on this forum. I lugged it into the yard today and had a play, I soon realised I need some help!.

I was cutting some 50x50mm square tube I had lying around and on a few occasions the unit stalled. The motor kept turning but the blade wasnt moving. I tried running the saw at the 2 lowest speeds but didn't notice a difference.

Can anyone suggest what the issue is, Blade Tension? Belt Tension? Downward force? I cranked up the tension on the blade for the last cut and it worked but I am not sure if this is the solution or just luck. Thinking about it now I am guessing its belt tension...

It also looks like I lost some teeth in the process too. I was using the factory installed 14 TPI blade. Is it normal to lose some teeth during use? Crappy Blades? Wrong TPI? or a result of too low of a tension mentioned above?

I have been trawling through youtube and noticed some users putting a few drops of oil on the steel before the cut. Is it worth doing, seems too little to do much to me?

Lastly, do you start the saw with the blade touching the work piece or start then place the blade onto the work piece?



Thanks

JJZ

The slipping bade could be due to either belt tension or blade tension or both. I think it important to get belt tension correct before attacking blade tension. 14 tpi is a bit too aggressive for cutting tube, depending on wall thickness of course, 18 TPI or finer is the go. The course blade will also cause a stoppage. I have installed a DIY coolant pump system on my BS-5S and highly recommend it. Start the machine and then bring the blade to the work. Try the search function, plenty has been written on bandsaws on this forum including the BS-5S.

Hi there,

The reasons for the stalled blade and (now) missing teeth can be many. As you mentioned, blade tension is important. Do you have a tensioning guide or gauge? Most machines will have some type of method for obtaining the correct tension. Too loose and the blade will slip on the wheel, do much tension and I assume you may snap/stretch the blade or put an unnecessary amount of stress on the frame.

Edit: did an image search of the model in question. It does not look like it has a tensioning gauge.

The loss of teeth sound like you may be cutting a too thin walled piece of stock for the blade pitch. There are many online guides to determine the blade pitch for a given type of stock but as a general rule I think you calculate to have about 6 - 10 teeth of the blade cutting the material at any one moment in time. Obviously for small stock or thin walled tube you need a much finer blade with a higher number of TPI (teeth per inch) BTW, you can cheat and (to a certain extent) cut thin walled stock with a blade considered too course but you need to be gentle and feed slowly and carefully.

Also the feed rate may have been too high, as in the rate at which the blade is fed into the stock. Too high a feed rate combined with a course pitch blade on thin walled stock is a sure fire way to loose teeth. Once one tooth is lost, it places more stress on the next tooth. Before you know it there is a domino affect and many teeth will be lost.

The cutting speed of the blade (measured in either feet/min or metres/s) can also be a factor but it's been my experience that a too fast a blade speed will cause premature blade wear rather than teeth loss.

Of course if it's the blade it came with then you may want to also question the quality of that blade too. Also make sure that the stock has not moved while cutting. This will jamb the blade, cause it to stall and also a sure fire way to loos teeth.

Cheers,

Simon

Originally Posted by simonl

a general rule I think you calculate to have about 6 - 10 teeth of the blade cutting the material at any one moment in time

Actually, the minimum number is 2 to 3. Other than that, Simon is quite right

Michael

Awesome Thanks everyone, I'll pickup some more suitable blades asap and double check my tensions.

Originally Posted by simonl

Hi there,

The reasons for the stalled blade and (now) missing teeth can be many. As you mentioned, blade tension is important. Do you have a tensioning guide or gauge? Most machines will have some type of method for obtaining the correct tension. Too loose and the blade will slip on the wheel, do much tension and I assume you may snap/stretch the blade or put an unnecessary amount of stress on the frame.

Edit: did an image search of the model in question. It does not look like it has a tensioning gauge.



Cheers,

Simon

Hi Simon,

I actually have a bandsaw tension guage that I used for woodworking if its suitable... What tension is recommended?

One of these : Bandsaw-Blade Tension Gauge - FineWoodworking


Joez

When you get new blades, make sure that they're BiMetal, they'll last a lot longer than the carbon blades that come with it. You'll also need to learn how to adjust the blades so that they cut straight and square. I've attached an article that'll guide you.

Attachment 365523
Kryn

Originally Posted by joez

Hi Simon,

I actually have a bandsaw tension guage that I used for woodworking if its suitable... What tension is recommended?

One of these : Bandsaw-Blade Tension Gauge - FineWoodworking


Joez

Hi Joez,

I think the blade tension would be specific to both the machine and the size of the blade. A 25mm blade will be tensioned much more than a 12mm blade, for example.

Do a google search for blade tensioning specific to your machine. failing this, surely there would be something mentioned in the owners manual regarding this?

Simon

I have the fixed version of that, called a "4x6 bandsaw" on the net - there's a *heap* of resources for these machines out there - just Google.

I use a 10-14 variable pitch bi-metal blade on mine, generally don't bother with lubrication and cut everything from bar to plate to sheet metal. If the blade is stalling, I'd crank up the blade tension, and check that the work is being held securely - if it shifts (or the blade does, since yours is a swivel-head) it can jam the blade.

There's also issues of blade alignment in all dimensions, of which there's plenty of 4x6 bandsaw articles, posts and guides on the net.

My BS has a 25mm x 0.9 blade (I think it's 0.9mm thick) and in an attempt to work out how much to tension the blade, I did a ggogle search on blade tension as a function of blade cross sectional area. I then worked out the force in Newtons that my blade should be tensioned.

The tensioning system on my BS uses a threaded take up and some heavy duty cone washers. I took these washers off and did some measurement of their deflection as a function of mass hung from them. I then extrapolated the expected deflection for the required force for the correct tension on the blade and then marked this on the BS thread. I use this as a guide for my blade tensioning.

My system is flawed for a number of reasons though. Least of which it does not allow for blade stretch and so over time the pre-set tension point will no doubt be less than what I initially calculated. Also, next time I need to purchase a new blade, it will be slightly different size and so the old mark will be irrelevant. The newer upper end BS have a hydraulic tensioner. I have played with them in the shop and they are fantastic. They use hydraulic pressure and a pressure gauge calibrated in tension to get the correct tension and work very well.

I had thought of making a blade tensioning measurer similar to what you have. It measures deflection of the blade over a given distance from a know spring tension, similar to pushing your finger on a fan belt to use as a guide to see if the belt is too loose.

BTW, I too use a Bimetal blade also a multipitch 10-14 made by Roentgen (something like that) and it has been fantastic. It's been on my BS for about 3 years now, done lots of work on MS and medium carbon steel and it just keeps going.

Also, 2 - 3 teeth in a workpiece at a time. What he said! Oops!

Edit: I never start the saw with the blade touching. I always start with the blade a few cm above. This gives me enough room to adjust the feed to the correct amount for the given workpiece BEFORE it starts cutting.

Cheers,

Simon

I pretty much agree with the advice offered so far.

The one thing I will add is that, to keep these saws working correctly, a higher tension than you might think is needed.
Most of my teething problems disappeared once I cranked up the tension on my saw.

Yep what Bob said

This seller sells decent bi-metal blades and posts them quickly and they arrive here amazingly fast, all for cheaper then buying them locally.

petoundakite | eBay

Hi joez,
I have the same saw and found that the weight on the blade creates too fast a cutting rate for cutting light gauge tube sections even with a finer toothed blade, you can adjust the spring to reduce it a bit but I found the best solution is to fit an adjustable hydraulic cyclinder to the arm to control the rate. I cut a lot of tube section and this has increased my blade life many fold. The blade tension and belt tension issues raised are also important as well. The link that RC gave is beauty as well, I purchased blade from this source and they preform very well. If you decide to go the hydraulic cyclinder route I can post some pictures of the set up I made up for my saw.
Bob

That'd be right, he appears to sell every size there is, except the one for the BS-5S, aaaargh!

Originally Posted by .RC.

This seller sells decent bi-metal blades and posts them quickly and they arrive here amazingly fast, all for cheaper then buying them locally.

petoundakite | eBay