Just put new tires on an inexpensive bandsaw (14" Chiwanese),
and found the upper wheel needed adjusting to an odd tilt.
Apparently the upper/lower wheels are not coplanar, because the band
doesn't adjust to center simultaneously on both.
I've tentatively identified the offset as 1/4 inch, and there's a joint
between the upper casting and lower casting, so I can shim there.
How does this happen? Did the factory mis-grind those castings, or
could it have bent somehow in use or transport?
Any words of wisdom before I pull out the big wrenches and
do the relatively-major disassembly?
On Tuesday, October 6, 2015 at 8:31:30 AM UTC-7, Leon wrote:
> On 10/6/2015 10:22 AM, John Grossbohlin wrote:
> > "whit3rd" wrote in message
> > news:[email protected]...
> >
> >> Just put new tires on an inexpensive bandsaw (14" Chiwanese),
> >> and found the upper wheel needed adjusting to an odd tilt.
> ... Was this a problem before you changed the
> tires? If not I would suspect the new tire installation.
It seems that low blade tension causes the symptom; I was trying
to adjust geometry before adjusting to full blade tension, after
removing the blade for the obvious reasons.
A long level used as straightedge does verify the wheels are coplanar now.
I'll check for flex at the joint next (clamps, scraps of iron, feeler gages).
Dealing with this machine gives me a new appreciation, too, for sheetmetal
design; they didn't get all their clearances right.
On 10/6/2015 10:22 AM, John Grossbohlin wrote:
> "whit3rd" wrote in message
> news:[email protected]...
>
>> Just put new tires on an inexpensive bandsaw (14" Chiwanese),
>> and found the upper wheel needed adjusting to an odd tilt.
>
>> Apparently the upper/lower wheels are not coplanar, because the band
>> doesn't adjust to center simultaneously on both.
>> I've tentatively identified the offset as 1/4 inch, and there's a joint
>> between the upper casting and lower casting, so I can shim there.
>
>> How does this happen? Did the factory mis-grind those castings, or
>> could it have bent somehow in use or transport?
>
>> Any words of wisdom before I pull out the big wrenches and
>> do the relatively-major disassembly?
>
> While the frame castings could be miss-ground so that the upper section
> is canted that seems like it would be the least likely scenario. Could
> it simply be that one or both wheels need to be repositioned on their
> shafts, and perhaps shimmed, to gain alignment?
A question to ask yourself. Was this a problem before you changed the
tires? If not I would suspect the new tire installation.
If the problem was there before, I would think that there is another way
to adjust the lower wheel. Many band saws have no upper and lower
section/half to adjust so the adjustment must be made at the wheels.
On 10/6/2015 3:34 AM, whit3rd wrote:
> Just put new tires on an inexpensive bandsaw (14" Chiwanese),
> and found the upper wheel needed adjusting to an odd tilt.
>
> Apparently the upper/lower wheels are not coplanar, because the band
> doesn't adjust to center simultaneously on both.
> I've tentatively identified the offset as 1/4 inch, and there's a joint
> between the upper casting and lower casting, so I can shim there.
>
> How does this happen? Did the factory mis-grind those castings, or
> could it have bent somehow in use or transport?
>
> Any words of wisdom before I pull out the big wrenches and
> do the relatively-major disassembly?
>
There are those that will tell you coplanar is not necessary.
I am not one of those. Once I got my band saw all straightened out, I
can use my fence to resaw.
My delta circa 2003 to 2005 I think did not even come close to lining
up. I had to remove the pins that register the upper arm.
For me, the drilling of the pins was in a way off space. REALLLLLLLY OFF.
Shim it to get it aligned, and don't look back.
--
Jeff
whit3rd <[email protected]> wrote in
news:[email protected]:
> Just put new tires on an inexpensive bandsaw (14" Chiwanese),
> and found the upper wheel needed adjusting to an odd tilt.
>
> Apparently the upper/lower wheels are not coplanar, because the band
> doesn't adjust to center simultaneously on both.
> I've tentatively identified the offset as 1/4 inch, and there's a
> joint between the upper casting and lower casting, so I can shim
> there.
>
> How does this happen? Did the factory mis-grind those castings, or
> could it have bent somehow in use or transport?
>
> Any words of wisdom before I pull out the big wrenches and
> do the relatively-major disassembly?
Certainly it's possible the castings were misground.
Bending is unlikely, since cast iron is fairly brittle
and more likely to crack.
I would use a long straightedge across both wheels to
confirm they're not coplanar. You should be able to
get the straightedge to touch at 4 points simultaneously
(top and bottom of both wheels). If you can't, adjust
the top wheel tilt for the same gap at top & bottom,
and that's the offset you're trying to correct.
Rather than seperating the castings, you can probably
fix the mis-alignment at the wheel. Sometimes one or
both wheels are fixed on their shaft with a setscrew,
and you can simply loosen the screw and slide the wheel
in or out. In other cases there are washers behind the
wheel (sometimes hidden under the hub), and you can
take the wheel off and add or remove to get the right
alignment.
BTW, it's probably good to check the alignment with
the saw tensioned with the blade you typically use.
Inevitably there's some flex, so getting it aligned
at a typical blade tension is worthwhile.
John
On 10/7/2015 5:06 PM, whit3rd wrote:
> On Tuesday, October 6, 2015 at 8:31:30 AM UTC-7, Leon wrote:
>> On 10/6/2015 10:22 AM, John Grossbohlin wrote:
>>> "whit3rd" wrote in message
>>> news:[email protected]...
>>>
>>>> Just put new tires on an inexpensive bandsaw (14" Chiwanese),
>>>> and found the upper wheel needed adjusting to an odd tilt.
>
>> ... Was this a problem before you changed the
>> tires? If not I would suspect the new tire installation.
>
> It seems that low blade tension causes the symptom; I was trying
> to adjust geometry before adjusting to full blade tension, after
> removing the blade for the obvious reasons.
You should adjust blade tension before adjusting anything else.
>
> A long level used as straightedge does verify the wheels are coplanar now.
> I'll check for flex at the joint next (clamps, scraps of iron, feeler gages).
> Dealing with this machine gives me a new appreciation, too, for sheetmetal
> design; they didn't get all their clearances right.
>
I have been down this road. Several years I upgraded from a Craftsman
so that I would not have to deal with these type issues. I'm sorry to
say that a $1,000. 18" Rikon was not good enough. Inexpensive and or
cheaply build band saws are a PIA IMHO. I finally got a Laguna and all
those issues are in the past. Laguna is expensive but I believe you are
always going to have some issue with a cheaply built band saw.
Next best bet would probably be an older model Delta, the ones built in
the USA.
On 10/6/2015 10:22 AM, John Grossbohlin wrote:
> "whit3rd" wrote in message
> news:[email protected]...
>
>> Just put new tires on an inexpensive bandsaw (14" Chiwanese),
>> and found the upper wheel needed adjusting to an odd tilt.
>
>> Apparently the upper/lower wheels are not coplanar, because the band
>> doesn't adjust to center simultaneously on both.
>> I've tentatively identified the offset as 1/4 inch, and there's a joint
>> between the upper casting and lower casting, so I can shim there.
>
>> How does this happen? Did the factory mis-grind those castings, or
>> could it have bent somehow in use or transport?
>
>> Any words of wisdom before I pull out the big wrenches and
>> do the relatively-major disassembly?
>
> While the frame castings could be miss-ground so that the upper section
> is canted that seems like it would be the least likely scenario. Could
> it simply be that one or both wheels need to be repositioned on their
> shafts, and perhaps shimmed, to gain alignment?
A question to ask yourself. Was this a problem before you changed the
tires? If not I would suspect the new tire installation.
If the problem was there before, I would think that there is another way
to adjust the lower wheel. Many band saws have no upper and lower
section/half to adjust so the adjustment must be made at the wheels.
"whit3rd" wrote in message
news:[email protected]...
>Just put new tires on an inexpensive bandsaw (14" Chiwanese),
>and found the upper wheel needed adjusting to an odd tilt.
>Apparently the upper/lower wheels are not coplanar, because the band
>doesn't adjust to center simultaneously on both.
>I've tentatively identified the offset as 1/4 inch, and there's a joint
>between the upper casting and lower casting, so I can shim there.
>How does this happen? Did the factory mis-grind those castings, or
>could it have bent somehow in use or transport?
>Any words of wisdom before I pull out the big wrenches and
>do the relatively-major disassembly?
While the frame castings could be miss-ground so that the upper section is
canted that seems like it would be the least likely scenario. Could it
simply be that one or both wheels need to be repositioned on their shafts,
and perhaps shimmed, to gain alignment?