On Jul 22, 11:00 am, "George" <[email protected]> wrote:
> "dpb" <[email protected]> wrote in messagenews:[email protected]...
> > Toller wrote:
> >> Grizzly has up graded their 17 and 19" extreme band saws by changing the
> >> trunnions to cast iron, and raising the price $200. Are cast iron
> >> trunnions really worth $200 (or 25%) more? The old saws actually weight
> >> a couple pounds more.
>
> > Depends...
>
> > If the previous designs have been found to be too light and flexible,
> > surely.
>
> Then there is the consideration that cast iron, as opposed to aluminum,
> doesn't make a good abrasive like AlOx, preserving the contour and
> clearance, thereby accuracy, for a longer time. Stamped metal isn't in the
> same league, of course.
Cast iron is harder. It machines better. It's rich in graphite,
which helps moving parts move smoothly instead of sticking
and galling.
On Jul 22, 1:47 pm, Gordon Airporte <[email protected]> wrote:
> Father Haskell wrote:
> > Cast iron is harder. It machines better. It's rich in graphite,
> > which helps moving parts move smoothly instead of sticking
> > and galling.
>
> I recall hearing that another advantage is the extra weight/density of
> cast iron, which gives the wheels more inertia, like flywheels.
Which dampens vibrations and helps machinery last longer.
Not sure why trunnions would need more inertia, though.
On Jul 23, 3:20 pm, Leuf <[email protected]> wrote:
> On Mon, 23 Jul 2007 16:56:18 GMT, Aardvark <[email protected]>
> wrote:
>
> >On Sun, 22 Jul 2007 11:09:49 -0700, Father Haskell wrote:
>
> >>> I recall hearing that another advantage is the extra weight/density of
> >>> cast iron, which gives the wheels more inertia, like flywheels.
>
> >> Which dampens vibrations and helps machinery last longer. Not sure why
> >> trunnions would need more inertia, though.
>
> >Possibly he meant momentum. Extra momentum in a rotating piece of cast
> >iron would minimise 'slowdown' in the blade when entering a workpiece
> >that's higher in moisture or denser or harder (like hitting a knot).
>
> >Just a guess. A WAG at that :-).
>
> He just confused the trunnion with the wheels. The trunnion is the
> cradle the table sits on that allows it to be angled. The only
> significant advantage would be if it keeps the table locked more
> securely. I dunno what the grizzly's are like, but once I lock the
> table on my delta if I try to move it the whole saw moves not the
> table. But that's also true of my little pos ryobi 9" bandsaw and I
> assure you there is no cast iron to be found anywhere on it.
>
> On my new grizzly 8" disc / 1" belt sander the table and trunnion for
> the disc table are both cast iron, however they didn't machine the
> mating surfaces, just rough painted castings that don't particularly
> fit well together. I mention this not to imply anything about
> grizzly's band saws, but just that sometimes they like to be able to
> throw around "cast iron!" this and that to look better on paper
> without actually being any better. I had to toss the trunnion in the
> trash and make my own fixed support to make it usable.
That's typical Chaiwanese craftsmanship -- cut back heavily on
finishing, finish only where it counts. I see they've lowered their
standards. It's time you learned the fine art of scraping cast iron.
On Mon, 23 Jul 2007 18:55:04 -0700, Father Haskell
<[email protected]> wrote:
>On Jul 23, 3:20 pm, Leuf <[email protected]> wrote:
>> On my new grizzly 8" disc / 1" belt sander the table and trunnion for
>> the disc table are both cast iron, however they didn't machine the
>> mating surfaces, just rough painted castings that don't particularly
>> fit well together. I mention this not to imply anything about
>> grizzly's band saws, but just that sometimes they like to be able to
>> throw around "cast iron!" this and that to look better on paper
>> without actually being any better. I had to toss the trunnion in the
>> trash and make my own fixed support to make it usable.
>
>That's typical Chaiwanese craftsmanship -- cut back heavily on
>finishing, finish only where it counts. I see they've lowered their
>standards. It's time you learned the fine art of scraping cast iron.
I really don't mind if they cut back and only do it where it matters,
but if they don't do it where it counts either then it's a problem.
I was supposed to be able to lock that table in place with the two
TINIEST wing nuts you've ever seen too. The motor pulley keyway
wasn't cut all the way through and the face was machined at an angle
( >.05" variation) which made it rather tricky to try to align the
pulleys. Grizzly sent me new pulleys, a new table, and even a new
sanding disc. The new motor pulley had the identical keyway problem
but was at least flat.
At the core of the machine it's a pretty slick design, the belt is
able to be setup to do internal sanding, and you can switch between
the two pretty easily. It's the only machine I could find that could
do internal sanding like that, and I had a specific application for
that. It's too bad they put their top priority as cost/ease of
manufacture, a distant second functionality, and little thought at all
to useablity. I've had to make lots of modifications, and I'm not
done yet. The platen is wider than the belt so you can't sand into
corners, or only on one side at a time. And it's held in place with
hex head bolts. Cuz yeah, I want to keep a 10mm ratchet next to the
sander all the time. So I'm going to have to replace those bolts and
grind an 1/8" off the platen. I'll probably find something else
after that.
-Leuf
"Toller" <[email protected]> wrote in message
news:[email protected]...
> Grizzly has up graded their 17 and 19" extreme band saws by changing the
> trunnions to cast iron, and raising the price $200. Are cast iron
> trunnions really worth $200 (or 25%) more? The old saws actually weight a
> couple pounds more.
Or course not, but there may have been other improvements, plus the cost of
raw material is skyrocketing so it was, perhaps, a good time to give an
overall increase.
On Sun, 22 Jul 2007 11:09:49 -0700, Father Haskell wrote:
>> I recall hearing that another advantage is the extra weight/density of
>> cast iron, which gives the wheels more inertia, like flywheels.
>
> Which dampens vibrations and helps machinery last longer. Not sure why
> trunnions would need more inertia, though.
Possibly he meant momentum. Extra momentum in a rotating piece of cast
iron would minimise 'slowdown' in the blade when entering a workpiece
that's higher in moisture or denser or harder (like hitting a knot).
Just a guess. A WAG at that :-).
--
Registered Linux User 413057.
Both Mandriva 2007.1 and Ubuntu 7.04
You can have it all. My empire of hurt.
Liverpool F.C.-more European Cups than all
the other English teams put together :-)
"dpb" <[email protected]> wrote in message news:[email protected]...
> Toller wrote:
>> Grizzly has up graded their 17 and 19" extreme band saws by changing the
>> trunnions to cast iron, and raising the price $200. Are cast iron
>> trunnions really worth $200 (or 25%) more? The old saws actually weight
>> a couple pounds more.
>
> Depends...
>
> If the previous designs have been found to be too light and flexible,
> surely.
>
Then there is the consideration that cast iron, as opposed to aluminum,
doesn't make a good abrasive like AlOx, preserving the contour and
clearance, thereby accuracy, for a longer time. Stamped metal isn't in the
same league, of course.
Toller wrote:
> Grizzly has up graded their 17 and 19" extreme band saws by changing the
> trunnions to cast iron, and raising the price $200. Are cast iron trunnions
> really worth $200 (or 25%) more? The old saws actually weight a couple
> pounds more.
Depends...
If the previous designs have been found to be too light and flexible,
surely.
As Edwin points out, metal costs have increased dramatically over last
several years as well as transportation costs (it costs Griz to get
stuff here before the transportation to you) and so on.
It is also true there's far more to "value" than simply material costs.
--
Aardvark wrote:
> On Sun, 22 Jul 2007 11:09:49 -0700, Father Haskell wrote:
>
>
>>> I recall hearing that another advantage is the extra weight/density of
>>> cast iron, which gives the wheels more inertia, like flywheels.
>> Which dampens vibrations and helps machinery last longer. Not sure why
>> trunnions would need more inertia, though.
>
> Possibly he meant momentum. Extra momentum in a rotating piece of cast
> iron would minimise 'slowdown' in the blade when entering a workpiece
> that's higher in moisture or denser or harder (like hitting a knot).
"Trunnions" don't rotate, however...
"Mass" would be the most likely relevant property related for them as
well as simply more strength/rigidity if as previous hypothesized the
former tended to be undersized so they flexed under load or warped when
locking in place...
--
On Mon, 23 Jul 2007 16:56:18 GMT, Aardvark <[email protected]>
wrote:
>On Sun, 22 Jul 2007 11:09:49 -0700, Father Haskell wrote:
>
>
>>> I recall hearing that another advantage is the extra weight/density of
>>> cast iron, which gives the wheels more inertia, like flywheels.
>>
>> Which dampens vibrations and helps machinery last longer. Not sure why
>> trunnions would need more inertia, though.
>
>Possibly he meant momentum. Extra momentum in a rotating piece of cast
>iron would minimise 'slowdown' in the blade when entering a workpiece
>that's higher in moisture or denser or harder (like hitting a knot).
>
>Just a guess. A WAG at that :-).
He just confused the trunnion with the wheels. The trunnion is the
cradle the table sits on that allows it to be angled. The only
significant advantage would be if it keeps the table locked more
securely. I dunno what the grizzly's are like, but once I lock the
table on my delta if I try to move it the whole saw moves not the
table. But that's also true of my little pos ryobi 9" bandsaw and I
assure you there is no cast iron to be found anywhere on it.
On my new grizzly 8" disc / 1" belt sander the table and trunnion for
the disc table are both cast iron, however they didn't machine the
mating surfaces, just rough painted castings that don't particularly
fit well together. I mention this not to imply anything about
grizzly's band saws, but just that sometimes they like to be able to
throw around "cast iron!" this and that to look better on paper
without actually being any better. I had to toss the trunnion in the
trash and make my own fixed support to make it usable.
-Leuf
On Mon, 23 Jul 2007 22:38:56 -0400, Gordon Airporte wrote:
> Leuf wrote:
>
>> He just confused the trunnion with the wheels.
>
> He did. Oops.
LOL. An earlier post in the thread mentioned cast iron wheels and it
seems I promptly forgot what we were talking about. First signs of aging
I suppose :-)
--
Registered Linux User 413057.
Both Mandriva 2007.1 and Ubuntu 7.04
You can have it all. My empire of hurt.
Liverpool F.C.-more European Cups than all
the other English teams put together :-)
"Aardvark" <[email protected]> wrote in message
news:[email protected]...
> LOL. An earlier post in the thread mentioned cast iron wheels and it
> seems I promptly forgot what we were talking about. First signs of aging
> I suppose :-)
>
You're not there yet if you don't recognize that the mind is the SECOND
thing to go....