Re: How to measure 4 x 6 bandsaw alignment
|
For adjusting the blade guides?here's some thoughts to bear in mind: 1. I mentioned in the 'Buying a 4x6' guide that to cut both horizontally?(your East/West?) and vertically (N/S?) square at the same time, the workpiece needs to be parallel to the pivot shaft
in both Plan View and Elevation
AND the sawblade needs to be square to the pivot shaft in both Plan View and Elevation. When Rick Sparber and I were trying to come to agreement over adjustment procedures, it came out that the above wasn't the easiest way to look at it. Now I think it is easier to separate the two types of squareness (since they can be adjusted separately): Horizontal squareness is achieved when the back of workpiece is parallel to the pivot shaft and the run of the sawblade is square to the pivot shaft when looking in Plan View (looking down from above the vice table) Vertical squareness is achieved when the bottom of the workpiece is parallel to the pivot shaft and the body of the sawblade?is square to the pivot shaft in Front Elevation? (looking across the vice table from the front) 2. You can always adjust any saw to cut horizontally square without difficulty, as it's only affected by the angles between the work, the sawblade and the pivot-shaft, the 'geometry' of the bits if you like.? However vertical squareness is more of a problem, because, although the saw can be adjusted to move geometrically as though it was going to cut vertically square, the blade can be thrown off line by what happens when
the teeth start to move, think of them as 'dynamic' effects.? Horizontal squareness is only about the geometry Vertical squareness is about both geometry and dynamics 3.Adjusting Horizontal squareness: a) Back of the workpiece parallel to the pivot shaft = Fixed vice jaw indicated parallel to the pivot shaft per the article as you noted b) To get the run of the?sawblade square to the pivot shaft, you shift the joint between the sawframe?and the pivot arm (LH rear of the sawframe?when it's horizontal) in the right direction until the test piece?you cut is parallel (per test on pg4&5 of the buying article) 4.Adjusting vertical squareness (You need to do them in the following order) a) Preparation:?
Adjust the side-guideroller-to-blade clearance with the eccentric on the bearing outside of the loop of the blade, until there is 0.000" to 0.001" clearance, i.e.?touching but not overtight, since this is what keeps the blade upright when cutting (The squareness of the blade body to the vice table changes when the roller-to-blade gap changes so its got to be adjusted first)? b) Blade body square to the pivot in front elevation =? blade body pretty much square to the vice table.? You judge and adjust this per the method on pg 14 in the Wilton 4x6 manual which is available in the files section as m_3130.pdf? ?(/g/4x6bandsaw/files/m_3130.pdf). This is probably the best manual of any 4x6 and you should print yourself a copy.? b) Bottom of workpiece parallel to the pivot shaft = vice table parallel to the pivot shaft.? As you've found out this is built into the saw at manufacture and can warp out of flat as the base casting ages.? That you've had to file yours, probably means it will not be parallel to the pivot, you'll find out just how much out it is by doing the test in the article. If it's?out by more than a few thou it is really annoying. If you've adjusted the blade back?square as in a) above then any vice table out of parallel will show up as taper in the test piece.? It can be temporarily fixed by packing up the low side of the infeed table with a strip of steel shim+double-sided sticky tape, until the test piece comes out parallel. A permanent fix?for this is probably the most difficult thing you can do to a 4x6. 5) Dynamic effects (the blade not cutting vertically down even when the geometry is correct) is mostly due to one of two things a) Too much weight on the teeth when cutting soft materials (like wood, plastic and aluminium) and the gullets of the teeth fill up which then tips the blade to one side?or the other (fix by holding up the sawframe?by hand so it doesn't cut so quick, or increasing the tension in the counterbalance spring (handle on LH front). b) blade worn or damaged on one side so it doesn't cut straight any more. (new blade is only fix)? ? Rick Sparber explains it a little differently from me and you should look up his article????.? Between the 2 explanations?you should be able to figure it out. Rgds - jv?? On Thu, Sep 24, 2020 at 8:22 PM <dpidwerbecki@...> wrote:
|
John Vreede