size of socket on extruder pinch-wheel shaft

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jferguson
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size of socket on extruder pinch-wheel shaft

Post by jferguson » Wed Aug 28, 2019 7:18 pm

Ok Guys,
The extruder pinch-wheel shaft has an allen socket with what looks like a tiny torx socket at the bottom. Now that I know I don't have a hex allen wrench in every possible size, what is it?

airscapes
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Re: size of socket on extruder pinch-wheel shaft

Post by airscapes » Wed Aug 28, 2019 8:07 pm

For the V4 is it 2.5mm for the bearing shaft screw if that is what you are asking.

jferguson
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Re: size of socket on extruder pinch-wheel shaft

Post by jferguson » Wed Aug 28, 2019 9:08 pm

airscapes wrote:
Wed Aug 28, 2019 8:07 pm
For the V4 is it 2.5mm for the bearing shaft screw if that is what you are asking.
I would have thought so. I need to go back and see exactly what I'm doing. could be pilot error.

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ednisley
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Re: size of socket on extruder pinch-wheel shaft

Post by ednisley » Thu Aug 29, 2019 6:44 pm

jferguson wrote:
Wed Aug 28, 2019 7:18 pm
what looks like a tiny torx socket at the bottom
That's the metal pushed downward while swaging the hex socket into the bolt head.

Basically, you drill a round hole into the bolt head, then force a hexagonal punch into the hole until it bottoms out, which scrapes six metal "petals" off the hole's wall and mashes them against the bottom of hole. The little tiny space remaining in the middle allows for punch pressure variations: a little oomph more closes the space, a little less opens it, but the hex hole turns out to be just about the same depth.

It's kinda hex-ish with points, but it's just a decoration. [grin]

jferguson
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Re: size of socket on extruder pinch-wheel shaft

Post by jferguson » Fri Aug 30, 2019 3:09 am

Ed,
This sounds like broaching. But why does the tiny hole have to be so nice?

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ednisley
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Re: size of socket on extruder pinch-wheel shaft

Post by ednisley » Fri Aug 30, 2019 2:15 pm

jferguson wrote:
Fri Aug 30, 2019 3:09 am
why does the tiny hole have to be so nice?
It's art! [grin]

AFAICT, a nice result means the manufacturing process is under control.

It works that way in my shop: when all my mistakes cancel out, even the swarf looks pretty!

jferguson
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Re: size of socket on extruder pinch-wheel shaft

Post by jferguson » Fri Aug 30, 2019 5:43 pm

Hi Ed,
Many years ago, Dad's outfit was presented with a warranty claim in Japan. An engineer was sent over to see what the problem was. When he was shown the equipment, his immediate response was "Not ours."
"Why do you say that?"
"it is too nice. We don't polish our castings"
As it happened it not only looked nice but was not the source of the Utility's problem, it was an un-arrested fault elsewhere in the system.

I don't know about your outfit Ed, but in mine, the senior people (the non-engineers) used to get squirrelly if the stuff we were making was nicer than it really needed to be.

Cheers.

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ednisley
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Re: size of socket on extruder pinch-wheel shaft

Post by ednisley » Sat Aug 31, 2019 1:21 pm

jferguson wrote:
Fri Aug 30, 2019 5:43 pm
about your outfit
Being a Retired Olde Farte™, my basement shop has a mirror for those face-to-face status meetings … [grin]

jferguson
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Re: size of socket on extruder pinch-wheel shaft

Post by jferguson » Sat Sep 07, 2019 3:57 pm

Once, more, it is stupid me. The allen wrench was not slipping in the socket, it was the nut on the other end of the shaft which was turning against the hex cavity. Duh.

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