Reamers can be some fun stuff. I hand reamed the spindle on a 1913 Sears
Expert (made by South Bend, an "Old, reliable" manufacturer that was all of 4
years old back then) 14" metal lathe out to just over 3/4". The ends of the
spindle bore were just a hair over 3/4" but in between was smaller and pretty
rough. I wanted to have it able to pass a 3/4" diameter bar all the way
through, so I made it happen, one small increment at a time.
On Friday, June 18, 2021, 11:07:09 AM MDT, Gerrit Visser <[email protected]>
wrote:
Reamers don't work well in nominal size holes. So always leave enough meat ofr
it to do its work. The attached link gives good info on that topic.
Machine reamers cut on the leading edge only, there is no taper. Hand reamers
have a taper, and won't cut to a shoulder.
If concentricity is the key goal, then drill well under size, bore to reamer
alloance and then ream.
https://www.fltechnical.com/news/reamer-guide-basic-technical-information-for-reamers
Gerrit
-----Original Message-----
From: John Dammeyer <[email protected]>
Sent: June 18, 2021 11:49 AM
To: Enhanced Machine Controller (EMC) <[email protected]>
Subject: [Emc-users] Machining question
This isn't as much a LinuxCNC question but more of an approach to how to
machine something.
The attached photo shows a coupler from a 3/8" encoder to 14mm Servo Motor so I
can test on the bench the Pi4 closed loop encoder behavior.
This one didn't turn out very well. I drilled all the way through and then
used a reamer to bring it to 3/8". It's a firm sliding fit on the encoder
shaft. Without removing it from the chuck I then drilled halfway to 13mm and
then used a 14mm reamer to bring it to size, testing with the motor shaft.
Problem was the reamer was slightly tapered at the front so it did a poor job.
I finished it up with the boring tool but maybe a few thou too large. However
the wobble seems much worse than that.
I'm thinking the better approach would be to drill all the way through
undersize 3/8" and then drill half way with 13mm. Then only use the boring
tool to bring the back half up to 3/8" and the front up to 14mm. This way if
the initial hole wasn't concentric with rotation the boring tool would ensure
it is.
Make sense? Or is there a better way?
Thanks
John
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