Bandsaw Drift

charlese · Post by **charlese** » Sun Sep 16, 2012 5:52 pm

marcp1956 wrote:... And what is flat sawing? Is this against the grain?

Now that we have been informed of the term "flat sawing" lets talk about bandsawing again. If you meant to say that laying a board on it's face and using the bandsaw is against the grain - that is true only if cross cutting. With the bandsaw it is possible to saw both across and/or with the grain, like sawing an arc or circle.

dusty · Post by **dusty** » Sun Sep 16, 2012 6:19 pm

Let me try this one more time. What is meant by "flat sawing"?

Scroll down a ways. Flat sawing and plain sawing are synonymous.

backhertz · Post by **backhertz** » Sun Sep 16, 2012 9:40 pm

This is interesting. I was told by Shopsmith technical support (a very reliable source) that this video was not applicable because their wheels are indeed co-planer. I took his word for it. I have never checked myself. I might has misunderstood. I know what was said on the Carter video, but the Carter guy said to check with the manufacturer. I called several months ago. Since then Doug Reid's posted a You Tube video for adjusting for drift on the Shopsmith PowerPro driven bandsaw.

But I'm not sure now about planer or co-planer. I never checked, so I can't say they are or not.

Found this on Highland Woodworking:
Question: "In your tool catalog you've said more than once that "making the wheels coplanar" on a bandsaw is an important part of tune-up, but as far as I know you haven't described how to do it. I have just a few questions: what does making the wheels coplanar mean, how do I know if I need to be coplanar, and if so how do I get my bandsaw wheels coplanar?"

Answer: "Hmm. Seems we've left a few details yet to cover, eh? The object of the exercise is to make your two bandsaw wheels lie in the same plane while you're cutting wood. When your wheels are coplanar, bandsaw blades tend to track stably, and perhaps best of all there's little or no adjustment required when you change blades. It's much more likely that your bandsaw blade will be perpendicular to the saw table, and your upper guides are less likely to require adjustment when you change depth of cut significantly."

I'm simply trying to get it right & know that many of you have far more experience than me. I just took a straight edge and held it against the wheels & found the straight edge to touch both wheels about an inch left of the wheel centers. So does that mean co-planer?

Tony

dusty · Post by **dusty** » Mon Sep 17, 2012 7:24 am

OKAY, if someone in technical support at Shopsmith says they are co-planar then "who am I to disagree".

I would, however, like for "him" to tell me what it means to be co-planar. I have a feeling that he and I have different opinions.

I also know that, on both of my bandsaws, the upper wheel is not in the same plane as is the lower wheel. The top of the upper wheel is back slightly (about 1/2° or 1/8") from the bottom of the wheel. The top and bottom of the lower wheel are equal distant from a vertical plane. This can be see (measured) by placing a straight edge on the end of both wheel hubs and viewing the relationship of the wheels (top and bottom) with respect to that straight edge.

Now I suppose my band saws could both be wrong; I'll not argue that point.

While doing this, give some thought to the purpose of the Auto-Track Roller Bearing (#56), part number 514011. If you go to your band saw right now and remove that bearing and then slowly turn the lower wheel (by hand), what happens to the band saw blade? Where does it track without the auto-track bearing? My guess, right off the back of the wheel.

PS: Actually, you must also remove the lower guide bearing too. It serves a secondary function of performing as a tracking bearing.

[ATTACH]18495[/ATTACH],[ATTACH]18496[/ATTACH]

BigSky · Post by **BigSky** » Mon Sep 17, 2012 8:55 am

No. The blade moved toward the back of the wheels but it did not run off. I would not bet on what would happen if I was to apply power though.

With the bearing installed my blade does not track in the same location on the two wheels. The lower wheel tracks more or less in the center while the upper wheel tracks off center to the rear.

pennview · Post by **pennview** » Mon Sep 17, 2012 9:35 am

Dusty, you are correct. The two wheels are not co-planar. If customer service says they are co-planer, then they have a different definition than other bandsaw manufacturers. The upper wheel is canted a bit on the Shopsmith and this is how the bandsaw was designed. It is an "odd-ball" set-up in that other wood cutting bandsaws require that the two wheels be on the same plane, i.e., co-planer, for proper alignment. On non-Shopsmith bandsaws, the upper wheel is adjusted (tilted) to ensure that the blade is tracking properly, somewhat similar to how one adjusts the belt on the belt sander.

The canting of the upper wheel on the Shopsmith bandsaw forces the bandsaw blade to ride toward the rear of the upper wheel, and two of the three guide bearings keep the blade from sliding off the back of the wheel. (On a typical bandsaw like the Delta, if the upper wheel were canted like the Shopsmith, the blade would fall off the back of the wheel because there are no support bearings to keep the blade on the wheel.)

The bearing on the left (near the tension adjuster) on the Shopsmith and the bearing below the table are meant to be in constant contact with the bandsaw blade. The bearing above the table is meant to be spaced away from the blade by a very short amount while the saw is running but not cutting; when cutting, that upper bearing should also contact the blade.

JPG · Post by **JPG** » Tue Sep 18, 2012 12:39 am

Perhaps 'co-planer' as used by the Carter guy and SS CS means the wheels are not rotated relative to each other about a vertical axis. i.e. the shafts are parallel when viewed from above or below.

The SS bandsaw upper wheel is also canted, but the shafts are still parallel when viewed from the top/bottom.

When viewed from the side(think sides of blade) the upper shaft will be lower at one end. The shafts are still parallel when viewed from the feed view(shaft end to end along their axis).

The SS bandsaw differs(canted upper wheel) in that it is 'co-planer' in only two directions. IMHO that makes the wheels non co-planer. The shafts are parallel in two of the three dimensions. co-planer wheels IMHO would require parallel shafts in all three dimensions.

Hope this does not require the use of NSAIDS to unnerstan!:D

keakap · Post by **keakap** » Wed Sep 19, 2012 5:17 pm

backhertz wrote:...
He maintains there should NEVER be drift on a bandsaw. Well, I'm not sure what he says applies to a Shopsmith bandsaw. To my knowledge, a Shopsmith does have drift and the fence is adjusted accordingly to compensate for blade drift.

Drift is cause by the saw blade teeth set more on one side than the other. If a blade is so set, it doesn't matter, afaIk, what brand saw it's on.
"should NEVER be drift on a band saw" is a rather strong term. But not a bad one, imho. It is said that if you can't get rid of the drift on a particular blade you're better off replacing it. BUT you can adjsut the fence to compensate somewhat in some cases.
Easy to get rid of slight drift. Stone the teeth on the aggressive side, basically. I've done that with any blade I use for resaw or with the fence. Other stuff- freehand- who cares?

foxtrapper · Post by **foxtrapper** » Thu Sep 20, 2012 6:02 am

Drift in my experience is strongly related operator impatience.

Use the right blade for the job, and run the wood through the blade at an appropriate feed rate appropriate, and you don't get drift. Start shoving the wood, and you can drift a blade completely out of the board.

pennview · Post by **pennview** » Thu Sep 20, 2012 8:52 am

As keakap stated, drift is the result of a blade cutting more aggressively on one side than the other, and this is the result of how the blade was manufactured. Blades that are stamped exhibit drift. Blades that are milled are better at controlling drift, but they too can exhibit drift. Scroll saw blades also exhibit drift.

If you don't want to angle your fence to compensate for the drift, you can use a stone to hone the aggressive cutting side of the blade, also as stated by keakap. Drift really isn't a problem, unless you want to make it one.