Thread: Hafco BP-16A Upper guide twist

Originally Posted by TTIT

Blade drift is dependant on each blade you fit and the tracking adjustment won't always give you enough adjustment to correct the amount of drift in some blades.

..........and just to add to that, even a 1/4 turn of the tracking knob will put the wheels out of coplanar.

The Duginske book suggests to use your widest blade which should be a 1/2" band for a 14" saw, get it tracking as close as possible to the centre of both wheels(on the crowns of the wheels) and then adjust the wheels for coplanar. Once that is all done, then adjust your fence to the drift.

On mine, there is not enough adjustment to allow me to run the band right in the centre so it is close to the centre which means I have to adjust the fence to the drift.

I probably could get it going in the centre, but the pulley is already about 8mm difference on one side to the motor, so I'm not pushing it......yet.

That Duginske book has edumacated me lots, highly recommended.

Originally Posted by baxter

1. American/Taiwanese band saws usually have crowned wheels which are best suited for cutting curves with medium to narrow blades - not saying that wider resaw blades can't be used, just more attention is required for tuning. The flat wheel design (actually has a slight curve/ crown) is used on larger industrial saws and some European machines.

2. Crowned wheels are used because it makes tracking very easy. The crown exerts a controlling force on the band, pulling the blade towards the top of the crown. This tracks the blade close to but not necessarily in the middle of the wheel. The top wheel angle exerts final control on the blade.

3. One of the big differences between the flat-and crowned-wheel designs is the amount of contact area between the tyre and the blade. The flat wheel design supports the blade body no matter what the size of the blade. The top of the crowned wheel only contacts about 1/4" of the blade. Thus, the largest blade that maintains full contact with the crowned wheel is the 1/4" blade. This is perhaps the justification for using the 1/4" blade for resawing. However, the 1/4" blade is not very stiff. To maintain stiffness on the blade, excessive tension is needed; this, in some cases, can damage the band saw, and in severe cases can lead to breakage of the wheel shaft.

G'day Baxter,

Far from boring, in fact it was a very good read and goes towards showing me just how much my FIL thinks he knows and what he doesn't.

I recently replaced a worn tyre on the bottom wheel and was going to shape the rubber (just bought some plain rubber from Clarke Rubber) so that it was crowned. "Don't need to do that, what a load of rubbish, won't make any difference", say he (who is always right and everyone is always wrong), I argued to a point and capitulated - just to keep the peace. When looking at rubber at Clarkes, FIL grabs some soft spongy rubber with a tape backing and tells me that it'll do the job. BS!

He knows a bit of stuff, but there's alot that he doesn't know or thinks he does and if he does - he's right and you're wrong.

Thanks for the info Baxter, it backed up what I had an inkling of, won't change farmer FIL opnion even if he read it - he'd judt say he's right and you're wrong. OK rant over. But excellent info that you posted.

Hi Guys,

I am in the process of buying my first bandsaw budget is a pretty big issue for me so I have been looking for second hand machines. I found a BP-16A at a resonable price and this thread has been invaluable!

The machine I am looking at has the older guides which need to be updated. I was considering the mod that others on this post have adopted but before I give it a go I was wondering about other options. I would prefer the bearing type guides instead of the solid ones and i was wondering if they could be installed on the BP-16A without too much trouble. Has anyone done this? If so, where did you pic up the new guides? Any tips on installing them would be fantastic.

Cheers,

gabacus.

Gabacus,

do a search here - there have been a few discussions about the types of guides, and changing between them.

This thread covers the guide upgrade pretty comprehensively.

http://www.woodworkforums.ubeaut.com...ad.php?t=33332

Cheers,
Andrew

Originally Posted by gabacus

..... The machine I am looking at has the older guides which need to be updated. I was considering the mod that others on this post have adopted but before I give it a go I was wondering about other options. I would prefer the bearing type guides instead of the solid ones and i was wondering if they could be installed on the BP-16A without too much trouble. Has anyone done this? If so, where did you pic up the new guides? Any tips on installing them would be fantastic.

Cheers,

gabacus.

If you have the older model with the extruded aluminium slide, the commercially available bearing type guides won't adapt without a heap of modification and would still be too flimsy at the end of it anyway. You really need to get rid of the ali' slide and get a decent chunk of steel on there to hold the guides first, then any type of guide can be attached to the end of the steel shaft. Here is the standard upgrade which you've probably already seen..

Thanks for the feedback guys.

i had a feeling this would be the case. all things considered the upgrade would cost me close to $200 (including the new r&p mod and bearing guides). may not be worth buying second hand. for an extra $100 i would be able to buy a new maching with a warranty so i think that will be the way to go...

cheers ,

gabacus