Thread: Hafco BP-16A Upper guide twist

Originally Posted by baxter

Martrix I am interested in reading what you post, but are you aware that your posts (and they are the only ones that I am aware of) overlap the width of the screen and I have to scroll sideways to read them.

Is anybody else having this problem. Is there a solution for Martrix or for me (be kind if answering the second alternative).

Yep, same problem. It'd help if he got rid of that graphic and just used some text

Rob

Or just reduced the size of the graphic, sure takes up a lot of screen real estate!

Originally Posted by mcarthur

Yep, same problem. It'd help if he got rid of that graphic and just used some text

Rob

Originally Posted by Big Shed

Or just reduced the size of the graphic, sure takes up a lot of screen real estate!

oh......

There is an option on your User CP that lets you turn off signatures so you don't see them. Ive had them off for a while and forgot about them altogether.

The option is under 'User CP' then 'Edit Options' and then take a look at the attachment.

I have reduced the size now anyway, so tell me if it fixes your problem maybe time for a new one.................carry on.

Well, there you go, didn't know about that option! Makes you stop and think why there are signatures anyway, don't it.

Anyway, smaller looks much better, but I probably will switch it off anyway!

Matrix, that's better now we only have to scoll up and down to read your input - notice that it revised your previous posts as well.

Now lets solve mcchaddy's problem as easily .

Michael I am taking the following from the book "Bandsaw Handbook" by Mark Duginske (Sterling Publishing Co, Inc New York). It is a very worthwhile reference and I would suggest you try to get access to a copy.

I will copy out some of what the author says (there are a number of pages, diagrams and photos). Some is my own summation of the text:

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.

4. The larger blades best suited for resawing are 1/2" blades. This means that only half of the 1/2" blade is supported by the 1/4" surface of the crown wheel. Larger blades such as the 1/2" blade can sway on the crowned wheel and increase the likelihood of vibration and harmonic flutter. Under heavy sawing stress, the blade can rock on the crown, causing the loss of tension, and causing lead and wander - lead is blade pulling in one direction: wander is when blade pulls to one side.



All this Michael to answer your one specific question. It appears that your 1/2" blade might be the one to use to check the co-planer. The author says that you are really conforming the bandsaw to the blade rather than the usual method of conforming the blade to the saw. Therefore, when you go to use the 1" blade you might have to check the co-planer for that blade.

I hope that this hasn't bored everybody, but it is a useful bit of information - there is much more on the subject in the book.

The use of washers in the alignment procedure is a suggestion alternative .

Michael, on the Jet 14" the top and bottom of the bandsaw are two separate sections with guide lugs to line up the sections before bolting them together. From what I can see on the H&F website, the BP16A may be one unit. If this is not the case, is there any potential for realignment to bring the entire top casing forward to overcome the co-planing problem?

Hi Baxter,

Thanks for the information. I have been trying to get hold of a copy of that book from our local library. All out at the moment.

However this afternoon I have finally had success with my Bandsaw. I put the 1/2 inch blade in and tensioned it to operating tension and guess what, wheels line up perfectly. I reinstalled the table and aligned the table to the blade. Then i reinstalled the new Upper bearing guide and shaft that i got today from H&F. Made sure the shaft was vertical and running in line with the blade. I had to add a small shim to the upper bolt that holds the assembley to the saw cabinet. Now the bearing guide sits straight and the blade runs in line with the rear thrust bearing.

Time for some tests cuts. Ran some old hoop pine and MDF through it and all came out the otherside square. The blade ripped through it like a hot knife through butter. There was a little blade drift but this was due to the fact that the fence was not aligned correctly to the blade. Also the tracking was probably a 1/4 turn out.

It took a while but i think i have finally got everything running smoothly. The saw has a distinctive hum now with no rattles or vibrations and i dont have to adjust the upper bearing guide everytime i raise or lower it different thickness timber.

Thanks for everyones help and advie.

Michael.

p.s. Baxter the BP16A is one piece, so no adjustment between top and bottom. Would be nice to have but.

Michael that is great news . Have many happy hours making sawdust.

As a matter of interest, did you leave the two washers in place or remove them?

You would probably find that your local woodwork retailer (Carba-tec or similar) will stock the Duginske book. $29.95 when I got my copy in 2004. You missed Christmas, but do you have a birthday coming up .

Hi Baxter,

I left one washer in there. I was at carbatec the otheday and they didn't one in stock. I was going to order it through timbecon.

Thanks

Michael.

If you're looking for a few books, it's worth checking at amazon.com.

Freight is a killer for a single book purchase, but if you are looking for several books, you can save a bundle. For example, the Duginske book is US$12.74 and the Lonnie Bird book is US$14.16

We're always buying books in our family, so we keep a list and check prices. Often, we save money (after adding the freight in) on just two books from Amazon. The other good thing is that they usually have stock.

woodbe.

I've had two more "projects" on my BP-16A, but now they're done I think I'm ready to actually start using it.

The original tyre had two sections where the rubber was corrugated, so H&F sent out a new tyre.
After I convinced the old one to come off, I compared it to the new one, and was a bit apprehensive about how much smaller the new tyre's diameter was.
Turned out to be no worry - it took a bit of persuading to get the new one one, and as I type this I wonder if it should have been glued on ???

Project 2 was to see if balancing the upper wheel would get rid of the machine's wobble.
A spin test showed that the top wheel always came to rest at the same position, so a couple of afternoons of grind a bit, spin, grind a bit, spin, etc.
gave me a top wheel which mostly stops at a random position.
I reassembled the machine, and the wobble is just noticeable on startup and stopping. Vibration when cutting is markedly reduced.

A few minutes adjusting so the blade tracks parallel to the fence, and I cut a sub-1 mm veneer of a bit of scrap
Yay!

OK, so some folks argue that these things should have been fine out of the box, but I've had fun, learned some stuff, and my big question is....

Why are there all these adjustable fences and jigs to correct the "blade drift problem" ?? Do lots of bandsaws lack a tracking adjustment, or is this some insiders' secret ???

Cheers,
Andrew
Happy BP-16A owner

Originally Posted by arose62

Why are there all these adjustable fences and jigs to correct the "blade drift problem" ?? Do lots of bandsaws lack a tracking adjustment, or is this some insiders' secret ???

Blade drift occurs because of misalignment, or just plain old variation (or wear) blade to blade. It's a case of get used to it, or change it before it's worn out. So the variable fences become quite useful to quickly setup for the current blade, especially if you change blades often.

Glad to see that you are a happy BP16A owner, it's a great machine!

Today, I got dragged down to the workshop by my youngest son to help him build and repair components for his wooden train track. We've built some raised track supports, repaired a turntable, and even built a new 'hump' to replace a missing part of the hump-back bridge. With careful measurement, most of the work is done by the bandsaw, and it's a pleasure to have such a competent machine in the workshop.

woodbe.

Originally Posted by woodbe

Blade drift occurs because of misalignment, or just plain old variation (or wear) blade to blade. It's a case of get used to it, or change it before it's worn out. So the variable fences become quite useful to quickly setup for the current blade, especially if you change blades often.

Why "get used to it" ?? Why not use the tracking adjustment ??

I thought blade drift was caused by the manufacturing process, hence the tracking adjustment so the bandsaw would cut parallel to the fence.

I feel I'm missing something here - surely it's easier to adjust the tracking knob 1/4 turn, than to make/buy an adjustable fence, or even to adjust one


Cheers,
Andrew

The other thing to take into consideration is the fact when the blades are joined together is that every blade will be slighty different, ie the back or front of the blade might be a smidgen longer or shorter which does effect blade drift

Originally Posted by arose62

Why "get used to it" ?? Why not use the tracking adjustment ??

I thought blade drift was caused by the manufacturing process, hence the tracking adjustment so the bandsaw would cut parallel to the fence.

Manufacturing process, wear and tear, can alter the tracking of the blade. I'm not saying don't use the tracking adjustment, but pointing out that you still have to get used to it when you cut freehand. I usually cut a bit of scrap first to get my eye in, but I'm no expert..

woodbe.