bandsaw tracking

[bluesman]

Just got my new Axminster (cheapo) bandsaw and setting it up. It says to set the blade central on the top wheel. It is impossible to get it running central, it tends to go to one edge or the other no matter how fine I try to adjust. The wheels have rubber round them and I'm wondering if even if I could get the blade centre, the teeth would dig into the rubber and damage it in which case it's better not to have it so central. As it happens it tends to run with the teeth just hanging over the edge of the wheel.

Also the blade hands over the edge of the lower wheel even more than the top. I reckon the two wheels are slightly out of alignment with each other which might be causing this difficulty in setting the tracking up. The lower wheel effectively pulling the blade out away from centre on the top one. There are 4 small bolts holding the axle of the bottom wheel so it looks like I could loosen them and slide the axle inwards a little to correct the misalignment but the instructions say this is factory set and the "datum" for the rest of the machine set-up and not to touch it unless absolutely necessary. What do you reckon guys?

 

[PowerTool]

I have a cheapo tabletop bandsaw,and the top wheel has adjustment for tilt (as well as tension) so managed to get mine running centrally on the rubber by altering that - does yours have the same/similar option?

Andrew

 

[DaveL]

Hi Bluesman,

Which model of saw have you got, that will let us look at the manuel from the Axminster site. Most of the small saws are clones of the EB bas315 type of saw, which I have.
I normally setup with the teeth just off the front of the tyre, as you suggest. It took me some time to get the hang of balancing the blade tension and the top wheel tracking adjustment to get the blade to run in the correct place.
You could move the lower axle but if you do that you will need to move the motor to keep the belt alinement correct, I would try the normal adjustments again before doing this.

 

[Lee Brubaker]

Not familiar with European make BS (us guys in North America are stuck with either Tiawanese, or Chinese saws supposedly built to the Brand Name specs). Fortunately my Delta was built in the U.S. prior to the manufacturing being farmed off shore. In any case the principals no matter where manufactured are basically the same.
Your upper & lower wheels should be coplanar. To check this, place a straight edge across both wheels close to the hubs. The upper & lower rims of both wheels should touch the straight edge. If not, then the wheels are not coplanar. To make them coplanar adjust the tilt until the upper & lower rims of the upper wheel are the same distance from the straight edge which you are still holding across the lower wheel. The resultant measurement is the amount the upper wheel requires shimming.
Once coplanar, the blade will track towards the front of the wheels but certainly not with the teeth overhanging the edge of the wheel. In many cases, when the wheels have been made to be coplanar, the owner has discovered that the prior tendency for the saw to want to cut at an angle instead of straight has disappeared (using a quality blade of course).
Hope this helps.

Lee

 

[devonwoody]

Before you undo any wheel axle setups, Release all blade bearings above the table and under so that do not interfere or touch your blade going through at any position of the revolution.

Then adjust tensions using the side knob and top adjuster until you get the satisfactory running position, then set up your blade bearings.

I can tell you by past experience that those blade bearings quite often have very inaccurate machined parts and if so in your case you will need to get intouch with your supplier because the machine I had there was not even enough meat left on the bearing set up to allow redrilling to the correct position.

Of course it could be the quality of your bandsaw blades causing the trouble, these have in the past had a terrible and diabolical reputation for being cr?><P

 

[bluesman]

Thanks everyone. The machine is Axminster AWSBS2 and yes it does have a tilt adjuster. I have the manual with it which tells you to set the blade to centre of the wheel. Turning the adjuster clockwise moves it to the back of the wheel. What happens is the blade tends to run with the teeth just hanging off the front edge. Minor adjustments seem to make no difference then suddenly it will shift to the back edge. Minor adjustments anticlockwise have the same effect - nothing then suddenly all the way again. Meanwhile on the lower wheel the band is almost half on and half off it. That doesn't seem to move wgen adjusting the top wheel which is what made me think it might need bringing forward on it's axle.

I'm not sure if I have the tension right either. It says a 3kG push in the middle of the band should distend it about 1/4 inch. How the hell do you guage a 3 kG push first? It seems as if it might be under tensioned (the manual says it's supplied like that and needs more) but turning the plastic tensioner knob needs a lot of force and feels like it might just shear off if I give it some stick.

The manual gives bearings adjustment info and I've set them up so none of them are giving any sideways pressure on the blade. The balde is the one supplied by Axminster so I guess a better quality one might make a difference.

I have tried a sample cut on a 1 inch thick piece of oak and it went through it like butter. I will only be using the machine occasionally and for the price it's probably OK but being a bit of a perfectionist and a (telecoms) engineer, I like things to work as they should but not having had a bandsaw before I'm not sure what is right or wrong with it.

 

[devonwoody]

I put my money on the blade quality being your problem.

I would recommend you get into touch with a certain blade supplier if the moderators let me. I reckon they would most probably take the blade back FOC if that didnt solve the problem.

 

[Sawdust]

I'd echo Lee's comments about getting the wheels coplanar. Mine is a different saw to yours but I had very similar problems; I could never get it to track properly or cut straight no matter what blade I had on it or how much tension I used, it would always wander to the left.

I spent some time making sure that the wheels were aligned exactly as Lee describes and since doing so it tracks perfectly on both wheels and cuts much better.

Also, as DevonWoody said, make sure you track it with all of the blade guides out of the way.

Good luck
Mike

 

[RogerS]

Hi bluesman

I also have one of these...my first bandsaw annd a little cracker.. :lol:

I have a Duredge blade fitted and it runs fine as far as I can see...but won't be able to check where it's lying on the wheels until next week.

One school of thought says tighten the blade until it sounds like a double bass when plucked...although they fight shy of saying if you are aiming for Bflat or Csharp :wink:

3kg push equals 3kg pull in my book...so you could get a spring gauge and pull the blade until it registered 3kg and then checked the deviation.

Make sure all your bearings are running freely. One of mine was locked and I didn't notice it until it was out of warranty. Not relevant to your original post but worth noting.

Even though I now have the Monstrous Beastie I think that I will still hang on to the wee one.

 

[ivan]

Bluesman, the behaviour of your blade (if it's OK) sounds as if it my be running on uncrowned wheels. Crowned wheel/tyres tend to centre the blade in the middle of the wheel - that's where it tries to run if it can - in the middle, where the diameter is a fraction more.

If the surface of the tyre is flat, uncrowned, the blade will be happiest with the teeth just off the front of the wheel. Maybe the manufacturer has stopped crowning the wheels, and it's not yet got in the manual?

If the wheels do have a flat surface it is usually then much more important to make sure each wheel is (more or less) in line, (co planar) or the blade may try to change position when you're not looking....Check this with a bit of tension on, and move either upper or lower wheel whichever easiest.

 

[Barry Burgess]

Bluesman I let the teeth of the blade overhang the wheel by was 1/8" or less on both wheels. I them apply some tension to the blade and turn the blade twice by hand to see if it moves reverse the direct of turn if it has moved so as to re align it.- adjust the tilt . Try again. Repeat this until it is not moving. Increase the tension on the blade and re test. If OK do the final tensioning.
Switch the band saw on and check again if there is any tracking.
The first few times it's a pain in the ass and takes time but it does get better.
I think that is why so many people don't change their blades that often.
Barry

 

[bluesman]

getting wheels coplanar might be difficult due to it having two seperate doors for access to wheels so can't get a single staright edge across them both at same time.

Ivan - you might have something there. It's hard to tell if wheel rubbers are crowned or not but they look flat to me. that might explain why it suddenly veers to one side when adjusting but tends to like running with teeth just overhanging

Barry - when you've finished setting up does it still run with teeth overhanging ?

devonwoody - I might get another blade anyway, this one is a 6tpi. I am mainly cutting smallish hardwood - do you think that is a decent type for a fairly fine cut? If i do it will prove one thing. How much should i pay for a fairly good one?

 

[RogerS]

For bandsaw blades, Dragon Saws get good reviews I hear and it also gives me the opportunity to list their new telephone number as they are moving premises this weekend. 01443 819910.

Usual caveats...no involvement etc..

 

[DaveL]

getting wheels coplanar might be difficult due to it having two seperate doors for access to wheels so can't get a single staright edge across them both at same time.

I would think a strip of ply or mdf could be cut to fit into the door opens to allow you the check the wheel alinement, of course the best tool to use is a band saw. :shock: :roll:

 

[devonwoody]

Bluesman,

Dragon saws are OK on price, free delivery, and a returns policy, I am unable to quote prices for obvious reasons.

.You mention you want a fine cut, does this mean you are going to cut dovetails or tenons?

For this sort of bandsaw work I used to use a 14tpi half inch blade but recently I have changed over to the M42 type which has varialble tpi and not a lot of rake. However it is a metal workers blade and you might want to get more experienced using traditional bandsaw blades and start at the bottom as my granddad said and work your way up.
(M42 blades are more expensive but I havent taken it out of my machine since the beginning of June, and it does everything for me, deep rips, and tenons etc.)

 

[bluesman]

DaveL - yes I was thinking along the same lines - thanks

devonwoody - as a newbie here I don't know where everyone is coming from. I'm guessing that someohow you are associated with the said company? My main use at the moment is for ripping down hardwood planks about 25mm thick into into strips about 35mm wide. Thinking about it and the result of my test drive on the machine, the blade is probably fine enough as the strips will be planed flat after anyway. I am thinking that maybe I will want to do some shaped cuts eventually so maybe a narrower blade might be useful. Still learning about all this stuff. As your garndad would have said i need to learn to walk before I can run so maybe I'll just stick with this for now and see how I can improve the tracking.

I got a book (Amazon) yesterday called "Small Bandsaw Techniques" by Robin Bishop. It's great for beginners like me. It actually talks about crowned and flat wheels and tracking. It says falt ones usually track with the teeth overhanging. Although my manual says to set it central I'm wodering if that advice is wrong - might ring Axminster for some input on it. still concerned that lower blade is only half on the wheel though.

 

[devonwoody]

Bluesman,


Please note I have no connection to Dragon Saws, only a satisfied customer, and introduction came about to them via this web forum.

The blade you are using to rip is a middle of the road grade which will rip and give a smoother finish than a 3tpi ripping blade and then also accommodate general purpose cuts. A 3 tpi blade gives a rougher finish but clears the saw dust through the machinery at a better rate.

 

[superunknown]

I have just taken delivery of one of these bandsaws, perfect for the kids to use!

Well I have to say its superb for the price.

Set up seemed straight forward on it, just some simple adjustments to the tracking.

I would say that the provided blade and the mitre fence are pretty rubbish.

 

[David C]

Half on wheel is clearly not right.

APTC have very good technical staff, call them.

Your blade should be near the centre of a slightly crowned wheel, both top and bottom.

Teeth hanging off the front is for monster resaws with flat steel wheels as far as I am aware.

David Charlesworth

 

[Lee Brubaker]

Bluesman:

A footnote on blades.....If you do any resawing do not cut circles, arcs, or bends of any sort with the blade that you resaw with, because that blade after doing so, will not cut straight for your resawing.
Do not store your resaw blade hanging on a wall hook for the same reason. Recoil it, attach it to the cardboard backer that it came with, then hang it up.
From some of the prior posts, I suspect that many woodworkers are not in the practice of reducing blade tension unless they are changing out the blade. By not doing so, speeds up the detrioration of the tensioner spring resulting in an unnecessary speed-up of the need to replace the spring. I never leave the blade tensioned for periods of overnight or longer.
My saw is now 8 years old & the spring is still in good shape.
Lastly, I use Swedish Silicone blades with milled teeth. They are designed to run at less tension than standard blades & cut accurately.
Setting the tension is done visually by setting the tension at the saw manufacturers' indicator for blade width. Remove the blade insert. Back off the upper & lower thrust bearings & guide blocks. Start the saw. Back off tension until the blade starts to flutter. Retension until the flutter disappears. The blade is now correctly tensioned. Thrust bearings should be set so that they are just clear of the blade & do not rotate until you start to cut. Guide blocks if metal should be spaced from the sides of the blade the thickness of a sheet of newspaper unless using cool blocks when they can be set to lightly touch the blade sides. Guide blocks should be positioned just shy of the teeth gullets.
If you are using zero clearance plastic blade inserts, drilling four spaced 1/2" holes in them will help your dust collector collect the cuttings so that they are not carried around & dumped on the table. To further assist your dust collector, install brass brushes to sweep the wheel tires clear of cuttings as the wheels rotate.
Hope these suggestions prove useful.

Lee