Advice before I put on riser block? (Coplanar attempt too...)

Page 4 of 4  

wrote:

at
Because that's what tracking adjustment *IS*. Adjusting where the blade runs on the tire. Tires are generally a little bigger than the largest recommended blade size.

"fudge
Yes, if it's new and it it grossly non-coplaner replace is the most appropriate advise. If it's modestly non-coplaner it probably does not effect the ctting ability of the saw. If it's used and grossly out if whack.... shim where you can to get it close.... then it's no linger an issue.

Huh?
won't
No, but the width an height of the crown can be measured. The radius of the crown can be calculated from that measurement, and what I call the fudge factor can calculated from radius and blade shift. My point was that a very subtle angular change caused by a blade shift results in a comparatively large distance in "fudge factor" because that small angular change is measured over the distance between the axels (3 or 4 feet)

justify
I can. For my saw. The tires are 1-3/8", max blade 1"... that's 3/16ths either way. YMMV
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ok, that's acceptable. Not for my BS, though. It's a chiwanese quasijunk model and the tires are narrow, almost flat and yet they say I can use a 1" blade. The tire is barely 1" wide. It will likely still allow for tracking adjustment, but with little or no rubber outside of the blade.

I agree - can we nail this advice into the foreheads of unisaw, BAD and the other "coplanar is a myth" crowd?

Much wider than mine - hence a difference in view between me and you. The replacement tires I've seen have all been narrow too. What BS is yours?
Mike
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It's so nice watching the kids play.
UA100
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Michael, you set yours up the way YOU want, and rest assured that my Powermatic works best as it came from the factory.
dave
Michael Daly wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

runs
tracking
Good. I glad we have found some common ground. Particularly sice we have been called "children".

Woodtek 18"
FWIW I ran the numbers and I was surprised by some of the numbers for My saw:
The wheel is 1-3/8 the tire is actually 1-1/4. The crown is about 3/32 The distance between axels is about 44"
From that, I calculated that the radius of the crown is a shockingly small 2.95" (lets call that 'r').
Lets suggest more modest 1/8th" blade shift. That means that at 1r (about 3") below the a upper axel the blade would pas back across plane defined by the upper wheel.
For each r thereafter, it would be 1/8th" back in the opposite direction from the shift. 44"/r -r = 13-2/3r
1/8" * 13-2/3 = 1.7" (my *calculted* coplaner fudge factor)
Adjustments for reality:
The crown is on my tires appears to be more like a triange than an arc this would tend to increase the fudge factor. The tires are mushy, This would tend to decrease the fudge factor.
I'll bet that the later has more impact. than the former. This supports my hypothesis that the fudge factor allowed by the crown on *my* BS is > the tolerances of even a half-assed manufacturing process.
I will aknowledge that the mushy tire factor makes this rather less than perfect, but at least lets us get our arms around the order of magnitude to which crowning can help mitigate a non-coplaner situation.
What practical lessons can we learn from this excercise?
I think it's clear that less crown makes a saw more vulnerable to non-coplaner issues causing a tracking problem. So if you have a "situation", shim if you can, but if you have old tires, replacing or recrowning *may* help considerably.
-Steve
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Something I knew intuitively, especially since my BS has flattish tires (certainly compared to yours). Watching the behavior of mine without covers on, with different degrees of co-planar and tracking makes it easy to agree.

Good advice. Certainly more useful that "coplanar is a myth". It also points back to the issue that folks with high-quality bandsaws that come well set up from the factory shouldn't be giving off-hand advice to the rest of the world.
This has been a useful discussion, I think.
Mike
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@primelink1.net says... <snip>

Steve,
There is no doubt that recrowning *does* help considerably. It's not a hypothesis, it is fact.
In a prior life I worked as a pinsetter mechanic. The mechanism used to send bowling balls back to the bowler is called the accelerator. Nothing but a large flat belt riding on two crowned pulleys (kinda like a bandsaur) with a ramp underneath. The ball gets caught in the ramp, the belt stretches as the ball climbs the ramp, and at the end of the ramp the ball comes out at about 15-20 mph. Can you imagine what happens when the crown on those pulleys wears down? No adjustment in the world would keep those belts in place, and you can adjust the pulleys front to back and left to right.
But, put new pulleys in there, and you could be so far OOW (out of whack) on the coplanar thing and the belt would track properly with no adverse effects, regardless of belt wear or adjustments made to the pulleys.
Both you and Mike are missing the point here. You're working so hard to calculate the OOC (out of coplanar) factor and the fudge factor that you've not addressed what the manufacturers say are acceptable levels of OOC. Nor do you address the fact that bands may actually *require* an OOC condition to run properly.
I've not found anyone here say that a severe OOC condition shouldn't be considered a drawback, or if one appears on a new bandsaw that it should not be addressed by the manufacturer's warranty. But there is a whole lot of information from a whole lot of knowledgeable folk here to support "coplanar is a myth". I guess I'd rather be cutting wood instead of fretting over a 1/8" deflection in my BS blade, especially since I don't know if that 120" blade is 100% true to begin with.
See my previous post about the 67 Mustang if you don't get it.
--
Regards,

Rick

(Remove the HIGH SPOTS for e-mail)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

On the contrary - I've specifically asked for any info that would define what an acceptable ooc would be. No one has come forward with any useful information with the exception of Steve (who's sort of working from first principles).

I can't remember seeing anything of the sort. Can you give a reference to a post by one of the coplanar is a myth crowd that actually does address this?
Mike
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@magma.notthis.ca says...

You've asked this group, but have you asked the manufacturers? IOW, Delta may say that 1/2" OOC is ok, while Jet says 1".

Not sure how to do this Mike - sorta like proving a negative. :-)
--
Regards,

Rick

(Remove the HIGH SPOTS for e-mail)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No, it's proving a positive. Just DAGS on this ng and find a post by one of the naysayers showing that they actually address the severe ooc condition. I only remember them saying, bluntly and unconditionally, that it's a myth and ignore it.
Mike
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 7 Apr 2004 22:52:27 GMT, "Michael Daly"

well, I for one have on more than one occasion fixed a bandsaw that was throwing bands by aligning the wheels....
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jeffrey Thunder wrote:

I think what's missing from the formula that's making up the sum (Hey! Math talk!) is that the band is riding the crown which means it's traveling under no more stress with coplanar as than without.
UA100
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
you just couldn't help yourself could you?
Try not to fixate on me as much. That way you can spend more time dealing with your other issues, at your next session. I assume you DO see a therapist?
dave
Unisaw A100 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The Pantload writes:

Care to recommend your's?
UA100
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Can't. I drove him crazy already. He's now locked up in a state mental ward.
dave
Unisaw A100 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hylourgos wrote:

My band saw (see short write up here)
http://www.owwm.com/PhotoIndex/detail.asp?id 3
is out but despite this it tracks fine. Being that it is tracking fine I elected to leave well enough alone.

I'm unsure where this analogy came from. I saw a request for opinions and responded. The next thing I know you're flashing a zip gun around and boasting about pipe bombs.
Grandma always told me, "Kee-Kee honey, never argue with an FGN". Of course grandma had a way with words and didn't initialize.
UA100
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
For what its worth: take readings on the pins with a caliper or micrometer once you separate the top casting from the bottom casting in preparation for adding the riser block. You may find the top of the protruding pin to be smaller than the base of the pin. Drilling at this point will reduce your saw to two very inefficient boat anchors. Taper pins are sometimes used to insure precision fit on castings. I added a riser block to a Rockwell 14 incher a few years back. The Rockwell did indeed use taper pins for locating the top casting relative to the bottom casting. No slop, no play, and no adjustment possible.
You might want to take time to pose this question over on rec.crafts.metalworking before you get the drill out and take the chance of making a very expensive mistake.
Dan "Eccentric by Nature"

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks Dan, that's exactly the kind of warning I'm looking for.
Regards, H.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 2 Apr 2004 12:36:50 -0800, snipped-for-privacy@sewanee.edu (Hylourgos) wrote:

3/8" seems a tad excessive.
Is the sucker running without any "slap", now.
You need to be at least a half-assed farm mechanic to set up some of these Chiwanese kit saws - and even the Delta that most of them are perversed-enginineered from.
Bandsaws are funny critters. They aren't available to the rectilinear tuneup stuff that you can do with a tablesaw. The whole deal is to wind up with a blade that will track well (or, at least predictably) under working tension. This can vary according to the parallelism of the wheels, the condition of the tires (tyres, Mike Hide), the width of the blade, the tension used on the blade for the type (tipe, bad), the kind of metal layup that is used for the blade, and the phase of the moon.
I once got excited about getting the blade to run without any side to side motion. I set the wheels up dead perfect under no load. I put in a 1/4" blade and cranked the tension up to that for a 3/4" blade (according to the pissant scale on the saw), and then cut with it. It cut fine and dandy for what I was doing.
Then I put a 3/4" resaw blade in it and it cut fine and dandy too, after I cranked up the tension a little bit - prior to that it wandered around.
Being a curious sort, I thought to get out my old timing light (saved from the days that I could still tune my own ride) and darkened the shop, so I could see what the blade travel looked like under the disco light.
Well, that were not pretty. The pulsing light showed a good deal of side to side travel on the blade - but the blade cut fine.
Fuggit. I put the disco light away and cut my stuff.
All I know is that you need to get the wheels moderately parallel and adjust your blade tension to the size of the blade. If the saw doesn't sound right, or cut right - you mess with the angle adjustment of the top wheel until it does.
If you run out of options - buy a Laguna - I hear they're real nice right ought of the box.
Thomas J. Watson-Cabinetmaker (ret) Real Email is: tjwatson1ATcomcastDOTnet Website: http://home.comcast.net/~tjwatson1
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
(Hylourgos) wrote:

I'm glad you asked me that. I had measured, but it was not careful. I went back out just now and reinstalled the top wheel. Where I had left the top wheel tilt adjustment was, I just now noticed, not on a parallel plane with the lower wheel. Once I did that and remeasured, more carefully this time, it was just a whisker under 1/8".
So thanks for the scepticism, it saved me some grief.
<snip>

<snip experiments that boil down to...>

Good advice. I'll see if I can't get this girl working right. If not, time to start a new piggy bank.
Thanks, H
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.