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  #1   Report Post  
Marcus Kellermann
 
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Default New Bandsaw Won't cut curves

I just purchased a new 14" Grizzly Utltimate Bandsaw with a 6 inch
riser block which gives it a 12 in capacity. After setting it up and
following the directions for tensioning the blade and setting the
glade guides (it has sealed bearing guides) it decided to test it out
using some scrape 3/4 plywood I had. Cutting straight lines went
fine, sure there was lead but that is to be expected. However when
attempt to cut a curve of about a 6 inch radius, the blade just twists
and the cut remains relatively straight. It has a 3/8 skip tooth
blade that came with the saw. I am sure it is a cheap blade and plan
on replacing it with a 3/16 inch TimberWolf blade. However it seems
like I should still be able to cut a curve with this blade.

Any ideas why it just twists? The thrust bearings is are thickness of
a business card from the blade and the guide wheels are just slightly
touching the blade. The blade guard is down to 1/4" above the work
piece.

Thanks
Marcus.
  #3   Report Post  
D. J. Dorn
 
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Default

I have the same saw and found the roller bearings to be a PITA - they work
off eccentricity and I found it difficult to adjust them properly. I
ordered the parts from Griz to hold standard guide blocks and not only is it
easier to adjust, it's a different saw. It cost $5.00 to switch it over and
I think it was the best $5.00 I've ever spent - with the standard rollers, I
was ready to sell the saw and buy a Delta.

Don

"Marcus Kellermann" wrote in message
m...
I just purchased a new 14" Grizzly Utltimate Bandsaw with a 6 inch
riser block which gives it a 12 in capacity. After setting it up and
following the directions for tensioning the blade and setting the
glade guides (it has sealed bearing guides) it decided to test it out
using some scrape 3/4 plywood I had. Cutting straight lines went
fine, sure there was lead but that is to be expected. However when
attempt to cut a curve of about a 6 inch radius, the blade just twists
and the cut remains relatively straight. It has a 3/8 skip tooth
blade that came with the saw. I am sure it is a cheap blade and plan
on replacing it with a 3/16 inch TimberWolf blade. However it seems
like I should still be able to cut a curve with this blade.

Any ideas why it just twists? The thrust bearings is are thickness of
a business card from the blade and the guide wheels are just slightly
touching the blade. The blade guard is down to 1/4" above the work
piece.

Thanks
Marcus.



  #4   Report Post  
LRod
 
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Default

On 29 Aug 2004 14:03:30 -0700, (Marcus
Kellermann) wrote:

I just purchased a new 14" Grizzly Utltimate Bandsaw with a 6 inch
riser block which gives it a 12 in capacity. After setting it up and
following the directions for tensioning the blade and setting the
glade guides (it has sealed bearing guides) it decided to test it out
using some scrape 3/4 plywood I had. Cutting straight lines went
fine, sure there was lead but that is to be expected. However when
attempt to cut a curve of about a 6 inch radius, the blade just twists
and the cut remains relatively straight. It has a 3/8 skip tooth
blade that came with the saw. I am sure it is a cheap blade and plan
on replacing it with a 3/16 inch TimberWolf blade. However it seems
like I should still be able to cut a curve with this blade.

Any ideas why it just twists? The thrust bearings is are thickness of
a business card from the blade and the guide wheels are just slightly
touching the blade. The blade guard is down to 1/4" above the work
piece.


Several things come to mind:

a business card is a little thick; I think most people recommend a
dollar bill (whatever that mikes out to, but I'm guessing half that
of a business card).

6" radius turn with a 3/8" blade (particularly a skip tooth) seems
tight to me.

I think it was already mentioned that the guide blocks should be just
behind the gullets in the blade.

Try a series of curved cuts with larger radii and work down to the
smallest that the blade will do without twisting. Surely it'll cut
SOME curve. I think you'll find that #2 in my list is the primary
answer, but a combination of all three certainly would make sense.


- -
LRod

Master Woodbutcher and seasoned termite

Shamelessly whoring my website since 1999

http://www.woodbutcher.net
  #6   Report Post  
GerryG
 
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Default

First suggestion: Change the blade.
Second suggestion: Tell us what kind of blade (incl. teeth/inch)

Yes, thrust bearings and guide blocks do help things. However, I always test
new blades with both out of the way. For the curve and wood you stated, I
wouldn't have any problem cutting it without any blocks or thrust bearings.

I'm assuming you have reasonable blade tension, reasonable feed rate, and that
the saw came with the typical blades they ship them with.

Curious,... on that note, the typical blade shipped is too small for the riser
extension, which would mean you bought another blade of some type. While some
of the cheaper blades are not too good, they are typically much better than
what ships with the BS, and I wouldn't expect those results. Typically, a
blade costing about 1/3 less than the TimberWolf should still give reasonable
performance, so what gives here?

One other possibility comes to mind. I assume you installed the riser. Did you
then check the BS alignment fully? I have a Jet-14, and had to knock the pin
out of my riser in order to get the wheels aligned with the blade centered in
the table slot.

GerryG

On 29 Aug 2004 14:03:30 -0700, (Marcus Kellermann)
wrote:

I just purchased a new 14" Grizzly Utltimate Bandsaw with a 6 inch
riser block which gives it a 12 in capacity. After setting it up and
following the directions for tensioning the blade and setting the
glade guides (it has sealed bearing guides) it decided to test it out
using some scrape 3/4 plywood I had. Cutting straight lines went
fine, sure there was lead but that is to be expected. However when
attempt to cut a curve of about a 6 inch radius, the blade just twists
and the cut remains relatively straight. It has a 3/8 skip tooth
blade that came with the saw. I am sure it is a cheap blade and plan
on replacing it with a 3/16 inch TimberWolf blade. However it seems
like I should still be able to cut a curve with this blade.

Any ideas why it just twists? The thrust bearings is are thickness of
a business card from the blade and the guide wheels are just slightly
touching the blade. The blade guard is down to 1/4" above the work
piece.

Thanks
Marcus.

  #7   Report Post  
Doug Miller
 
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Default

In article , (Marcus Kellermann) wrote:
I just purchased a new 14" Grizzly Utltimate Bandsaw with a 6 inch
riser block which gives it a 12 in capacity. After setting it up and
following the directions for tensioning the blade and setting the
glade guides (it has sealed bearing guides) it decided to test it out
using some scrape 3/4 plywood I had. Cutting straight lines went
fine, sure there was lead but that is to be expected. However when
attempt to cut a curve of about a 6 inch radius, the blade just twists
and the cut remains relatively straight. It has a 3/8 skip tooth
blade that came with the saw. I am sure it is a cheap blade and plan
on replacing it with a 3/16 inch TimberWolf blade. However it seems
like I should still be able to cut a curve with this blade.


Yes, you should.

Any ideas why it just twists? The thrust bearings is are thickness of
a business card from the blade and the guide wheels are just slightly
touching the blade. The blade guard is down to 1/4" above the work
piece.


Well, that's too much gap between the blade and the thrust bearings (the
thickness of a piece of typing paper, or a new dollar bill is more
appropriate). It's unlikely, though, that this is enough, by itself, to cause
the problem you describe.

The guide wheels may not be properly positioned: the wheels should be just
behind the gullets between the teeth. You may not have enough of the blade
supported between the guide wheels.

And you may not have the blade tension set high enough.

You don't indicate your level of experience with bandsaws, so please pardon me
if the following is way off the mark, but the trouble may be in your
technique. To cut a curve with the bandsaw, it is necessary to feed the wood
into the teeth _as_ you rotate it through the curve. Simply rotating the
workpiece, without feeding it at the same time, will twist the blade but not
cut anything. Same principal as driving a car: just turning the steering wheel
won't get you out of a parking space. You gotta be moving forward in order to
turn.

--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)

Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter
by sending email to autoresponder at filterinfo-at-milmac-dot-com
You must use your REAL email address to get a response.


  #8   Report Post  
 
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Thanks for the suggestions.

I am using the blade that came with the riser block kit, It is a 3/8"
x 105" x 6 TPI blade. I am not sure who is making them for Grizzly but
their site claims it is made in the USA.

Interesting that you say you test without the guides in place. I
always thought that was a no/no.

I just double checked all of the alignments on the BS and everything
looks fine. Table is is square and plumb to the blade, the wheels are
coplaner and the blade is ridding on the crown of the wheel.

I don't have another blade to test with so, I'll stop and pick up one
from the local Woodcraft store tomorrow. This is my second BS, I
originally had a 12" Delta but it was underpowered for what I want to
do. I wouldn't call myself a begginer but I am definitly not a season
verteran on the BS.

-Marcus

  #9   Report Post  
 
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This is my second BS, I originally had a 12" Delta but it was
underpowered for what I want to do. I wouldn't call myself a begginer
but I am definitly not a season verteran on the BS.

I just moved every the thrust bearings closer and readjusted the guide
bearings so they are 1/64 behind the gullet on the teeth. (They were
about 1/32 to 1/16). But still have the same results. I insured that
I was rotating the board as I feed it into the blade at a reasonable
rate, but still the same thing. I can cut circles in cardboard just
fine :-) But even in 3/16 thick ply it twists. I even tried turning
up the blade tension.

I'll get a new blade tomorrow and see what happens. Currently blade is
a grizzly blade, 3/8" x 105" x 6 TPI blade.

Thanks,
Marcus

  #10   Report Post  
 
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Intersting, do you think it is just a flaw in the Grizzly's guide
wheels or do you just prefer guide blocks in general

Thanks
Marcus



  #11   Report Post  
Vic Baron
 
Posts: n/a
Default

I'd really suspect he tensioning. I've cut curves fine using a properly
tensioned blade with out the thrust bearings. As long as the blade is sharp,
should be no problem. Of course, this is only for testing.

I'd double check the spring also. I have a griz 0555 and the first time I
tensioned it, I had problems. Took a bit but I found that the screw thread
in the tensioning spring had hung on a rough spot so it would appear to be
tensioned when it wasn't. Fixed that and all has been well since.

Vic
wrote in message
...
This is my second BS, I originally had a 12" Delta but it was
underpowered for what I want to do. I wouldn't call myself a begginer
but I am definitly not a season verteran on the BS.

I just moved every the thrust bearings closer and readjusted the guide
bearings so they are 1/64 behind the gullet on the teeth. (They were
about 1/32 to 1/16). But still have the same results. I insured that
I was rotating the board as I feed it into the blade at a reasonable
rate, but still the same thing. I can cut circles in cardboard just
fine :-) But even in 3/16 thick ply it twists. I even tried turning
up the blade tension.

I'll get a new blade tomorrow and see what happens. Currently blade is
a grizzly blade, 3/8" x 105" x 6 TPI blade.

Thanks,
Marcus



  #15   Report Post  
GerryG
 
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Default

Ahhh....a BS manufacturer supplied blade...in THAT case...
Here's a good one to try: cut the circle in the OPPOSITE direction.
Not a real solution, and I'm actually just curious, but that will tell you if
the teeth are worn (or bad) on just one side.
In any case, I'd go for a new blade.

Regarding the guides, they do help, but when and how much will rarely be found
in the books. It's the narrow blades that need the thrust bearings more
(fairly obvious), and the guide blocks do little except for cutting curves,
unless you hit the edge of a knot or hard curved grain.

Maybe four years ago on the wreck, a bunch of us looked at resawing 4-12"
hardwood, and what blades and technique would produce the best results. With a
good blade on a well tuned BS, one test involved setting the guide blocks
nearly touching, maybe 4 mils away, and removing them entirely. Examining the
roughness of the cut, I couldn't find any difference. A similar test with the
thrust bearing (note: 3/4" blade here) showed little effect until the bearing
was actually deflecting the blade at all times. Further examination showed the
blade weld wasn't perfectly straight (flat, linear, whatever). IOW, if you
placed the blade back down on a jointer bed, you could measure about an .032
gap.

This is an item I've never seen mentioned in any woodworking books. From
machinest's land, a typical tolerance here would be .004. The blade
distributor didn't know what it should be, but agreed .032 was too much and
sent me new blades. These measured (I think...) .010. Rerunning the previous
thrust bearing test, I found less effect from the bearing, and the resultant
smoothness was better in all cases.

An easy way to get a quick measure of this in place, is to rotate your upper
wheel by hand, while measuring the min/max movement of the back of the blade.
Of course this brings other adjustments into it, but it's quick, and if it's
good then it's good.

At the other extreme, both the thrust bearing and guide blocks helped when I
was cutting many curves in 6" hardwood. I also learned (after the fact, of
course) to vary the direction instead of cutting all curves the same, which
will wipe out only one side of the blade.

If memory serves me right, I believe that John White was the only author who
really discussed this in detail, and I highly recommend his articles.

GerryG

On 29 Aug 2004 18:41:20 -0700, wrote:

Thanks for the suggestions.

I am using the blade that came with the riser block kit, It is a 3/8"
x 105" x 6 TPI blade. I am not sure who is making them for Grizzly but
their site claims it is made in the USA.

Interesting that you say you test without the guides in place. I
always thought that was a no/no.

I just double checked all of the alignments on the BS and everything
looks fine. Table is is square and plumb to the blade, the wheels are
coplaner and the blade is ridding on the crown of the wheel.

I don't have another blade to test with so, I'll stop and pick up one
from the local Woodcraft store tomorrow. This is my second BS, I
originally had a 12" Delta but it was underpowered for what I want to
do. I wouldn't call myself a begginer but I am definitly not a season
verteran on the BS.

-Marcus



  #16   Report Post  
GerryG
 
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Default

Did you run this issue back to the Timberwolf distributor or manufacturer?
They are far from perfect, but I've used many of their blades, as have many
others here. I've had some issues, and they adressed them. Same with Lee
Valley when their product was defective. I'll just note it's interesting that
you're resawing 11" with a 1/4" blade.
GerryG

On Sun, 29 Aug 2004 23:26:58 -0500, WD wrote:

On 29 Aug 2004 14:03:30 -0700, (Marcus Kellermann) wrote:

STOP! Don't buy Timberwolf.

I have the same problems you encounter and I bought two Timberwolf's blades and
I am disappointed. So I got Lee Valley 1/4" blades, it work like a charm. I can
saw very tight radius including resaw up to 11" .

Try Lee Valley blades it cost no more than Timberwolf, but perform better. Do
you trust Lee Valley? Almost everyone here will tell you Lee Valley is a good
company to business with.

I just purchased a new 14" Grizzly Utltimate Bandsaw with a 6 inch
riser block which gives it a 12 in capacity. After setting it up and
following the directions for tensioning the blade and setting the
glade guides (it has sealed bearing guides) it decided to test it out
using some scrape 3/4 plywood I had. Cutting straight lines went
fine, sure there was lead but that is to be expected. However when
attempt to cut a curve of about a 6 inch radius, the blade just twists
and the cut remains relatively straight. It has a 3/8 skip tooth
blade that came with the saw. I am sure it is a cheap blade and plan
on replacing it with a 3/16 inch TimberWolf blade. However it seems
like I should still be able to cut a curve with this blade.

Any ideas why it just twists? The thrust bearings is are thickness of
a business card from the blade and the guide wheels are just slightly
touching the blade. The blade guard is down to 1/4" above the work
piece.

Thanks
Marcus.

  #17   Report Post  
Unisaw A100
 
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Default

Some people use a dollar bill for band saw set up, some use
a hunnert. For the thrust bearing I back it off, the
bearing, not the dollar bill, a sixteenth or so then start
the saw up and slowly (vewy, vewy slowly) start to dial it
into the back of the blade until it just starts to spin
intermittently, vewy, vewy intermittently.

Now, an embarrassing question, and you don't have to answer,
is the blade on right side down?

UA100
  #18   Report Post  
John McCoy
 
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"Vic Baron" wrote in
m:

I'd really suspect he tensioning. I've cut curves fine using a
properly tensioned blade with out the thrust bearings. As long as the
blade is sharp, should be no problem. Of course, this is only for
testing.


That was my first thought. But he mentioned turning up the tensioning,
with no effect. He also says he can cut in something soft (cardboard),
but not in wood. So my guess is that his blade has no set, and the
back of the blade is binding against the side of the kerf.

John
  #19   Report Post  
 
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Resolution!!!!

Nate Perkins and John McCoy were right on the money. I stopped by
WoodCraft and picked up a new 6TPI 105" Timberwoof blade today. Before
installing it I checked the set of the teeth of the old blade. Yep,
they were almost dead even with the rest of the blade. So off it went,
on goes the new blade and everything is great! I am able to make cuts
the size of nickles while pushing the wood with 1 finger and no effort.

I suspect that in my early "tuning" now called "butchering" of the
setup, that I got the guide bearings to close to the teeth and that
pinched them shut. I checked the 93" blade that came with the saw
and the set is proper on it.

Thanks for Everyones advice, I now know and understand what happend and
how to prevent it in the future.

-Marcus

  #20   Report Post  
Vince Heuring
 
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Default

In article , D. J. Dorn
wrote:

I have the same saw and found the roller bearings to be a PITA - they work
off eccentricity and I found it difficult to adjust them properly. I
ordered the parts from Griz to hold standard guide blocks and not only is it
easier to adjust, it's a different saw. It cost $5.00 to switch it over and
I think it was the best $5.00 I've ever spent - with the standard rollers, I
was ready to sell the saw and buy a Delta.

Don


Dan, what are the part numbers for the standard guide blocks? Are they
in the Griz catalog?

TIA, Vince

--
Vince Heuring To email, remove the Vince.


  #21   Report Post  
Ron Magen
 
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Marcus,
Just a note / hint / tip . . .

About a year ago, after a LOT of agonizing, I bought a 14inch bandsaw. {Yes,
I looked at the Griz, but decided on a JET}. The saw came with their
interpretation of 'Cool Blocks'. Because I didn't think I would be using
narrow blades, I swapped them out for Ceramic ones.

I set up the machine and really haven had any problems. I don't use it a
great deal, so the unit is actually BETTER them I AM - at the moment. 1/4
inch is the thinnest blade used - to date.

I have the original blocks in the 'parts box', and will probably make a
couple of 'sets' from hardwood {WD40 impregnated ?}. The reason is simple -
I have a couple of projects / plans that will require 1/8 in blades. From
what I have read {and experienced with the 4Tpi 1/4 in blade}, there is
another level of control when you can 'bury' the blade beyond the gullet.
There *REALLY* isn't much to work with on a 1/4 inch . . . I can only
imagine a 1/8 inch.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

wrote ...
Resolution!!!!

SNIP
I suspect that in my early "tuning" now called "butchering" of the
setup, that I got the guide bearings to close to the teeth and that
pinched them shut.



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