On Sat, 19 Feb 2011 17:21:06 -0500, Joseph Gwinn
wrote:
In article ,
Doug White wrote:
Joseph Gwinn wrote in
:
In article ,
Doug White wrote:
I get promotional emails from Rutland Tool, and they have a sale
going on that caught my eye:
http://www.shoprutlandtool.com/wcsst...Upload/Rutland
_Emails/OB115.html
Down at the bottom, they have a Noga Flex Gage Holder marked down
from $99.17 to $53.95 (have to use promotion code OB115 at checkout).
I've had one of these for about 15 years, and it is the one I use
almost all the time. It's very easy to set up at weird angles, has a
good reach, and it's plenty rigid once it's locked down. It's also
the smallest magnetic base I've seen with the quick release button.
I think I paid close to $75 for mine, and considered it a good deal.
No relationship to Rutland, etc. If I didn't already have one, I'd
snap this up in an instant. As it is, I had to wrestle with whether
I really had any use for a second one.
I've always wondered how well those things worked, in particular how
firmly the clamps prevent creeping, and how firmly the magnet sticks
to a cast iron table.
Is the reach really only 2.2+2= 4.2 inches?
That's the length of the arm. My indicators add a couple inches to that,
and depending on how you set it up, the base adds a bit of height as
well. I've hardly ever had an issue with it not reaching. Mostly I use
it to center stuff on my lathe, and it's planty long enough for that.
It's a little short for my uses.
When locked down, it's quite rigid.
That's good to know. That was my worry.
I've also used the Flexbar holders.
The small ones aren't nearly as nice as this unit, and the next step up
is huge by comparison.
http://www.flexbar.com/shop/pc/FLEXBAR-Universal-Holder-Positioning-Arms-c69.htm
When you unlock these, they flop all over. I find the two rigid arms
easier to deal with.
I have one of these, bought used. It does work, but is a bit springy,
and will droop if not perfectly adjusted. I did take it apart and clean
it, which helped a lot.
I designed this with the Noga holders in mind, though the central
clamping mechanism is different. The arms are 12" long, and it'll
resist about 40 lbf at full reach.
http://www.nedsim.com/news/Arm00.JPG
http://www.nedsim.com/news/Arm03.JPG
The key is getting the bending in the arms right, such that the leaves
at the central joint come together only after there's adequate
clamping force on the balls at the ends, but before reaching the yield
point of the steel.
Has anyone disassembled a Noga holder? I have a picture in my mind of
what the guts may look like, but didn't have one availabe to take
apart while I was working on this arm.
--
Ned Simmons