I have a 4x6 probably 25/30 years old. It has always had a problem of
throwing the blade[the blade comes off while cutting]. The problem as
become progressively worse. If you remove the blade and spin the idler
wheel you can feel a roughness in the ball bearings. When taken apart
and the bearings rotated against a moving belt they seem fine. My
conclusion is that the bearing seats are not co-axial.

Now the questions:

Does this seem like a reasonable conclusion? If not what might be the
problem?

If so what can be done about it? I thought about turning down the shaft
so the bearings don't bind and seating them to the shaft with Locktite.

Any and all solutions will be appreciated.

Thanks in advance.

Chuck P.

Pilgrim fired this volley in newsilgrim-
:

I have a 4x6 probably 25/30 years old. It has always had a problem
of
throwing the blade[the blade comes off while cutting]. The problem
as
become progressively worse. If you remove the blade and spin the
idler
wheel you can feel a roughness in the ball bearings. When taken
apart
and the bearings rotated against a moving belt they seem fine. My
conclusion is that the bearing seats are not co-axial.

Now the questions:

Does this seem like a reasonable conclusion? If not what might be
the
problem?

If so what can be done about it? I thought about turning down the
shaft
so the bearings don't bind and seating them to the shaft with
Locktite.

Any and all solutions will be appreciated.

Thanks in advance.

Chuck P.


You suggested contradictory treatment vs. problem. IF the bearings
are so worn that the shafts are no longer in alignment, replace the
bearings. The shaft doesn't run in the bearing, it's a snug or press
fit in the inner race of the bearing. The shaft does not rotate IN
the inner race, it rotates the race itself, and any wear is between
bearing elements.

Turning down the shaft would worsen the condition.

I have an old, well over-used 4x6. The blade jumps more now than it
did when new, but seldom when the blade is sharp and the feed rate is
correct. Dull blades exacerbate the problem a lot. And despite the
wear on my saw, if the blade is sharp and the feed rate is correct, it
cuts a straight line.

Even on the cheapest Chinalloy saws, all the wear parts are
replacable, except maybe the tire on the driving wheel, and perhaps
the gear-box gears.

LLoyd

Lloyd E. Sponenburgh writes:

I have an old, well over-used 4x6. The blade jumps more now than it
did when new, but seldom when the blade is sharp and the feed rate is
correct. Dull blades exacerbate the problem a lot. And despite the
wear on my saw, if the blade is sharp and the feed rate is correct, it
cuts a straight line.

Mine never cut square when it was new out of the box, then I replaced the
cheap guide bearings with good ones (size 6200 2RS), and wow, this thing
cuts a 2.5 inch bar so square with a sharp blade, that the out-of-square is
inside the "nap" of the cut.

"Richard J Kinch" wrote:
Lloyd E. Sponenburgh writes:

I have an old, well over-used 4x6. The blade jumps more now than it
did when new, but seldom when the blade is sharp and the feed rate is
correct. Dull blades exacerbate the problem a lot. And despite the
wear on my saw, if the blade is sharp and the feed rate is correct, it
cuts a straight line.

Mine never cut square when it was new out of the box, then I replaced the
cheap guide bearings with good ones (size 6200 2RS), and wow, this thing
cuts a 2.5 inch bar so square with a sharp blade, that the out-of-square
is
inside the "nap" of the cut.

Interesting fix; it's good to know of another mode to watch for these saws
to cut out of square. From the 4x6 group over on yahoo, some have noticed
that this can also be caused by the pivot rod (bed to bladewheel assembly
hinge) holes being improperly positioned.

Jon

Poor cutting performance as far as cutting a straight downward cut can also
be due to other reasons, Jon.

The set angle/tilt of the upper saw section, where it's supported by the
strut, and a lot of end play in the hinge pivot rod can also increase the
chances of unwanted blade drift from the intended/desired path.

Using washers and shaft collars can position the upper saw section in a
fixed position on the hinge pivot rod.

Shims added to the strut that support the upper saw section can also improve
the direction of the blade travel.

Both of these solutions are described here (with pitchers 'n stuff, too)

http://www.kwagmire.com/shop/saw/4x6saw.html

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Jon Danniken" wrote in message
...
"Richard J Kinch" wrote:
Lloyd E. Sponenburgh writes:

I have an old, well over-used 4x6. The blade jumps more now than it
did when new, but seldom when the blade is sharp and the feed rate is
correct. Dull blades exacerbate the problem a lot. And despite the
wear on my saw, if the blade is sharp and the feed rate is correct, it
cuts a straight line.

Mine never cut square when it was new out of the box, then I replaced the
cheap guide bearings with good ones (size 6200 2RS), and wow, this thing
cuts a 2.5 inch bar so square with a sharp blade, that the out-of-square
is
inside the "nap" of the cut.

Interesting fix; it's good to know of another mode to watch for these saws
to cut out of square. From the 4x6 group over on yahoo, some have noticed
that this can also be caused by the pivot rod (bed to bladewheel assembly
hinge) holes being improperly positioned.

Jon

Reducing the shaft diameter would worsen the problem, Chuck, IMO. Even if
the bearings aren't positioned perfectly parallel to each other, a small
degree of error wouldn't matter a lot at the slow speed of the blade wheel.
I can't recall from memory just how the bearings are situated, but if there
is a spacer between them in a single bore, I'd check that the ends of the
spacer are parallel.

If the ball bearings aren't perfectly centered axially, this would likely be
more of a problem, IMO, but since the hole(s) is/was probably cut in one
operation, I would expect them to be positioned relatively accurately.

My 4x6 is not so old, but I haven't had any problems with the blade walking
off the wheels, and the saw has seen considerable use.
Before I used the saw, I practically disassembled the entire machine, and
checked the alignment of almost everything as I reassembled it.
I noted that shimming the free wheel was required to bring it to the same
plane as the drive wheel.
I placed a tap handle (the long type not the T-handle type) on the input
pulley shaft and wound the blade around by hand while watching the tensioned
blade go around.
Looking back now, a variable speed drill motor would've probably been
easier, but it allowed me to see that the blade was tracking properly in
slow motion (although not cutting any metal).

Some other details of the 4x6 bandsaw are he
http://www.kwagmire.com/shop/saw/4x6saw.html

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Pilgrim" wrote in message
news
I have a 4x6 probably 25/30 years old. It has always had a problem of
throwing the blade[the blade comes off while cutting]. The problem as
become progressively worse. If you remove the blade and spin the idler
wheel you can feel a roughness in the ball bearings. When taken apart
and the bearings rotated against a moving belt they seem fine. My
conclusion is that the bearing seats are not co-axial.

Now the questions:

Does this seem like a reasonable conclusion? If not what might be the
problem?

If so what can be done about it? I thought about turning down the shaft
so the bearings don't bind and seating them to the shaft with Locktite.

Any and all solutions will be appreciated.

Thanks in advance.

Chuck P.

On Wed, 31 Dec 2008 10:52:55 -0800, "Jon Danniken"
wrote:

"Richard J Kinch" wrote:
Lloyd E. Sponenburgh writes:

I have an old, well over-used 4x6. The blade jumps more now than it
did when new, but seldom when the blade is sharp and the feed rate is
correct. Dull blades exacerbate the problem a lot. And despite the
wear on my saw, if the blade is sharp and the feed rate is correct, it
cuts a straight line.

Mine never cut square when it was new out of the box, then I replaced the
cheap guide bearings with good ones (size 6200 2RS), and wow, this thing
cuts a 2.5 inch bar so square with a sharp blade, that the out-of-square
is
inside the "nap" of the cut.

Interesting fix; it's good to know of another mode to watch for these saws
to cut out of square. From the 4x6 group over on yahoo, some have noticed
that this can also be caused by the pivot rod (bed to bladewheel assembly
hinge) holes being improperly positioned.

Jon


Indeed. Line bored out of square.

Which means you put a shim on the base plate where you lay your stock
Its best to put in a .25 plate that covers the entire work area, and
simply shim up one side or another and screw it down permanantly.

Gunner

"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary
that Roosevelt would be remembered as a great president, "maybe even
alongside Washington and Lincoln," opining that Roosevelt "had every
quality that morons esteem in their heroes.""

Or just make all of your projects out-of-square, then cut one leg shorter
(possibly two).

Otherwise, there was one owner I read of, that sawed off the cast ears and
replaced them with pillow blocks.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Gunner Asch" wrote in message
...
Indeed. Line bored out of square.

Which means you put a shim on the base plate where you lay your stock
Its best to put in a .25 plate that covers the entire work area, and
simply shim up one side or another and screw it down permanantly.

Gunner

"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary
that Roosevelt would be remembered as a great president, "maybe even
alongside Washington and Lincoln," opining that Roosevelt "had every
quality that morons esteem in their heroes.""

"Wild_Bill" fired this volley in
:

Otherwise, there was one owner I read of, that sawed off the cast
ears
and replaced them with pillow blocks.

--
WB


Wouldn't it have made more sense to plug the holes, and re-bore them?

????

LLoyd

That's probably a good solution, Lloyd. One thing that I can think of as far
as adding the pillow blocks is; it starts to look more like a real machine.

Kinda like the cars sitting along the side of the interstate highways with
about $3000 worth of new wheels and tires on them.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Wild_Bill" fired this volley in
:

Otherwise, there was one owner I read of, that sawed off the cast
ears
and replaced them with pillow blocks.

--
WB


Wouldn't it have made more sense to plug the holes, and re-bore them?

????

LLoyd

On 2008-12-30, Pilgrim wrote:
I have a 4x6 probably 25/30 years old. It has always had a problem of
throwing the blade[the blade comes off while cutting]. The problem as
become progressively worse. If you remove the blade and spin the idler
wheel you can feel a roughness in the ball bearings. When taken apart
and the bearings rotated against a moving belt they seem fine. My
conclusion is that the bearing seats are not co-axial.

Now the questions:

Does this seem like a reasonable conclusion?

I'm not sure about the bearing at all.

If not what might be the
problem?

Typically, these have an Allen setscrew below the upper wheel
bearing block which tilts the upper wheel to control the angle so you
can minimize the chance of the blade walking off.

Aside from that -- you *do* know that the proper tension for the
blades is as tight as you can possibly turn that plastic blade
tensioning knob by hand? Actually -- that gets the blade to the low end
of the proper tension range. You *can't* grip it hard enough to
over-tighten the blade.

If so what can be done about it? I thought about turning down the shaft
so the bearings don't bind and seating them to the shaft with Locktite.

Try the bearing block tilt adjustment screw first -- and the
belt tension knob.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Wed, 31 Dec 2008 17:45:09 -0500, "Wild_Bill"
wrote:

Or just make all of your projects out-of-square, then cut one leg shorter
(possibly two).

Otherwise, there was one owner I read of, that sawed off the cast ears and
replaced them with pillow blocks.


Im going to have to do that with a largish Spartan automatic saw in the
not to distant future. Previous owners didnt bother to lube anything,
and over a period of years, the unbushed saw frame pivot holes went not
just out of round, but keyshaped.

It will be faster and easier to simply install pillow blocks with
movable mounts and dial the sucker in, than busting it all down, welding
the holes up, then finding someone to line bore it, then putting it all
back together again


"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary
that Roosevelt would be remembered as a great president, "maybe even
alongside Washington and Lincoln," opining that Roosevelt "had every
quality that morons esteem in their heroes.""

Gunner wrote:

Indeed. Line bored out of square.
Which means you put a shim on the base plate where you lay your stock Its
best to put in a .25 plate that covers the entire work area, and simply
shim up one side or another and screw it down permanantly.

Simple, elegant, and easy to implement. Thanks Gunner, that's an excellent
solution!

Jon


** Posted from http://www.teranews.com **

On Dec 31 2008, 6:00*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Wouldn't it have made more sense to plug the holes, and re-bore them?
LLoyd

It might if your machines are large enough. You could install pillow
blocks with a hand drill.

jw

In article ,
"Wild_Bill" wrote:

Thanks for the reply. The bore[s] for the bearings were done in two
operations. One from each side. That is why I think the bores may not be
coaxial.

Chuck

* * * * Aside from that -- you *do* know that the proper tension for the
blades is as tight as you can possibly turn that plastic blade
tensioning knob by hand? *Actually -- that gets the blade to the low end
of the proper tension range. *You *can't* grip it hard enough to
over-tighten the blade.

I used a strap wrench on mine, and eventually stripped the plastic
handwheel off the jack screw. I made a new handle with a crank on it,
and then ended up breaking the upper bearing block at the large axle
hole, where the cross section is the smallest. I ended up welding it
up with nickel rod and sistering a piece of 1/4" plate to it, also
welded with the nickel. I've not had a lick of trouble with that part
since, though I've now replaced the blade guide bearings and the main
gearbox bearings and seals.

If the main gearbox (drive wheel) bearings are bad (or going) it will
definitely mess with your tracking. Depending on how long they've
been bad, your main gear may also be toast due to running out of
position. There's guys on eBay selling the gear, shaft, and one of
the two bearings as a unit.

--Glenn Lyford