200kg Elektra Beckum Paper Weight...

[seaco]

I started this on another thread as I was going to buy an Axminster bandsaw but it was in Kent a bit to far away and so Mark here on the forum won it and so the story begins...

I already have an Elektra Beckum BAS450 bandsaw made in 1982 it is quite large probably as big as the Axminster but since I've had it it's been unreliable no matter what I do to the wheels the blade will track to the front or back and even sometimes centrally when it does it cuts sweet as a nut but it won't stay that way for more than one session of use?

On the other thread it has been suggested that the wheel tyres could be knackered and could have become concave, I looked and photographed it today and to me it looks slightly convex is that enough...

I did replace the wheel bearing about 4 months ago and it hasn't had much use due to it being unreliable and I've noticed that the top wheel will move a few mm again why do you think this might be?

As you can tell I don't know to much about bandsaws so any help would be appreciated.

Here are some more pics, excuse the mess I'm just adding an extension to my workshop...

 

[ivan]

There's been quite a bit on bandsaw tracking, search the forum for the full SP.

Causes of instability:

badly welded blade/try a new one

poor or no crown/yours looks OK, both wheels should be the same. Crown about 1mm minimum, maybe more if tyre is very soft. (Should be ground, but a bit of tape inder the tyre centre is a short term cure if the tyre is not glued on) Saws with flat tyres track the blade with teeth just over wheel edge.

most likely the wheels are not in line (co planar) A straight edge should be able to touch top and bottom of both wheels at once/saw may have screw adjustment or use/remove packing washers. Check this with blade on and under tension, all guides backed off. When the wheels are more or less coplanar the normal tracking adjustment will work fine. If theyre a long way out, the blade is fighting the poor alignment and may track unpredictably. Spin by hand to check how youre doing. Make sure blade tracks close to wheel centres with all guides backed off the blade, before resetting the guides.

 

[OLD]

ivan has covered everything but the few mm movement should be looked into, you have the machine i am sure you can solve it .It may help to take off the table and make up a suitable straight edge to clear the metal casings when checking the wheel alignment and don't forget to tension the blade correctly

 

[seaco]

Thanks for the replies Ivan and Old I think I will have to check the wheels are co-planar as for blade tension I've never known how to set this I read to loosen guides have about 6" of blde showing then put moderate pressure on the blade and it should deflect about a quater of an inch, but what's moderate for me may be light to someone else etc?

Is there a better way short of buying an expensive meter?

 

[ivan]

The top wheel will be 'loose' with the blade off; when you adjust the tracking, you are tipping the wheel back or forward, so it has to pivot. Usually it will also move a bit from side to side, to allow the wheel to align itself with the fixed bottom wheel. Could be this is what you feel, if so, this is nothing to do with a duff bearing.

Best to take off the table and guides, fit a blade and tighten till it sounds a bit like a bass guitar (exact tension not critical), and test that the wheels are co planar. You may have to make a straight edge with a big notch in the middle to clear the frame. Imagine a clockface on the wheel; st. edge should touch at 7 and 11 on teh left hand side, on top and bottom wheels, and 5 and 1 on the rh. If teh top wheel needs tilting to get it right, adjust the tracking so the wheel is parallel to the st. edge. The gap, if there is one, shows how much one or other of the wheels needs moving. Sometimes the manufacturer allows undoing a bolt or two to move the bottom wheel in or out a bit, or you may have to add or remove washers from the top one. Moving the bottom wheel may necessitate moving belt pulleys to keep v belts aligned. Look carefully before you start!

Once this is right, the tracking adjustment will correct for minor blade errors and saw will run OK. Don't put the table and guides back on till you've got this bit right.

I use a Lidl 10 quid digital caliper as a tension gauge (I did a post on this) but for a start 1/4" deflection with a firm push will do. Tension is only of serious importance when you want to make very deep cuts. Never tighten the tension knob to the point that the spring coils touch, or it won't be a spring any more! Good luck, looks like it could be a useful machine when sorted.

Lonnie Bird Also wrote a useful guide to using your bandsaw.

 

[seaco]

Hi Ivan

I will test for co planar but a couple of questions how do you use the digital caliper as a tension gauge also is this the book you mean http://www.eruditor.com/books/item/9781 ... 91.html.en

 

[WellsWood]

Never tighten the tension knob to the point that the spring coils touch, or it won't be a spring any more!

Actually, loooking at the pictures it seems to suffer from one of the same shortcomings as my smaller bas315 in that it has no spring.

 

[ivan]

I assumed (common cause of errors!) te spring was behind the folded box section underneath the wheel centre. What's the verdict, Seaco?