Bandsaw Questions

[9fingers]

I've been restoring an old 3 wheel Startrite bandsaw (model 18-s-1).

All bearings have been changed both in the drive system and guides. All three bandwheels have a reasonably smooth surface (not glazed) and with about 3mm of rubber
I'm finding it is very twitchy in getting the tracking right. Making quite a large adjustment to the adjustable wheel make little difference and then suddenly the blade will veer off and similar behaviour when adjusting it back the other way.
This give a large range of uncertainty as to where the correct operating position should be.

Having discussed this with another mechanical engineer, he has raised the point that really only one wheel needs to be crowned. this will make the blade climb to the top of the crown and the blade should run over other two wheels in roughly the same position. The adjustment wheel then compensates for any twist in the frame. (unlikely as the machine is built like a brick lavatory).

So now for the question.

Do any of your saws only have one crowned wheel or are they all crowned?

And another Q

Does this effect sound familiar?

TIA

Bob

 

[ivan]

My only 3 wheel saw was more paper than bricks...but your mate may have something there. In 2 wheeled saws it is sometimes reported that the blade position is not stable when both wheels are crowned, and also not in the same plane Presumably in this situation both wheels 'fight' for control. Lord knows what happens if you've three!

Try to make sure all 3 wheels are set in the same plane, this may need some spacer washers. That should make things a bit more comfortable!

 

[9fingers]

Thanks for the reply Ivan,

I'll try and rig something up to check the wheels are coplanar. Not easy over such a wde spacing.
I found out from a Startrite spares dealer today that all three bandwheels are the same (and only £70.00 each - splutter!) and are crowned.
I think the crowns must have worn off mine as they are as near as damnit flat. I think I'll have a shot at crowning one first and see if it becomes 'boss'

At 70 notes each, I don't want to waste any more rubber than I have to.

Regards

Bob

 

[pepi]

Hi Bob
Just read your post! I have an old three wheeler as you know also built like the poverbial. The only wheel that is crowned is the top adjusting wheel the others are flat. As you know I have just had to re-tyer one wheel, the reason for this I am sure was that I misguidedly took the advice of spraying the bandsaw's tyer with V-Belt dressing to try and put back some elasticity in the rubber. I was fortunate enough to restrict this trial to one wheel!!!
It caused the blade to stick to the wheel and pull the rubber apart. with limited damage to the other two.
Please don't try it!!!
After you have trued the wheels up and made sure they are running in plain if you are still having the problem this may be a cause.
some time ago i read in a book about tuning bandsaw's about a similar problem to your. The culprit was found to be the uneven detrition of the wheels tyer across the width on one wheel. Just maybe this could be it?
Hope it helps.
KR Pete

 

[Woody33]

Please can some kind member tell me exactly where the tracking knob is. I have a 352 and the blade continually slips to the front despite setting in the middle of the wheels. The guides are fine as are the wheel treads. There is only one tightening control knob and the manual mentions a tracking control on the rear of the saw body. The only thing there is a a control to release the belt tension, secured in place by a bolted angle device to prevent slipping. So where is the thing? I know there must be an easy answer but the instructions aren't making any sense.

Tony

 

[9fingers]

That sounds totally different from my three wheeler but there are lots of 352 owners here so hopefully one will be along to help you

Bob

 

[Argus]

Please can some kind member tell me exactly where the tracking knob is. I have a 352 and the blade continually slips to the front despite setting in the middle of the wheels.

Tony

Tony, The tracking adjuster on a Startrite(?) 352 is a knurled knob in the centre of the upper wheel.
You release the guides so that the blade is running free of any thrust back or forth and (power OFF!) rotate the thing by hand until it sits in the crown of the upper wheel when it is being spun. You only need to move the adjuster a little at a time.
I have a PDF of the manual if you send a PM with your e mail.

Regards from Wales

.