Something is not right...

FIRST General Forum
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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]

Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 2/9/2000 6:11 PM MST

Hi all,

In update #8 the following is found:

Drive Assembly Output Screw thread: M10 x 0.1 Right Hand
Internal locking thread: M5 x 0.8 Left Hand

Something is not right here. For one thing, the pitch is DEFINITELY wrong, probably a typo. If it is metric, it is an M10 X 1.0 Right Hand thread (not a 0.1 pitch as listed).

BUT, the thing that I am confused about is that I know I have made adaptor shafts in the past with 3/8 x 24 threads in them. They worked fine for a few years.

While 3/8 (.375 inches) is close to 10mm (.394 inches), close is not the same.

Also, while 24 pitch (.042 inches per thread) is close to 1mm pitch (.039 inches per thread) again, they are not the same.

So… I would be surprised if a 3/8-24 nut would thread easily on an M10 X 1.0 screw.

In addition, I have not found a Jacobs Chuck (which I believe these drill have on them) that has a metric thread in it.

Anyway, perhaps Jacobs has gone metric after all, or perhaps Bosch has changed chuck suppliers, or perhaps an M10x1.0 screw accepts a 3/8-24 nut, or perhaps I am a crazy person.

That is just it… …I don’t know.

Does anyone else know? If so… do tell.

Joe J.

2

Posted by Ken Wilson.

Engineer on team #248, FEMEX, from Philadelphia Girls High and PECO Energy Company.

Posted on 2/10/2000 4:39 AM MST

In Reply to: Something is not right… posted by Joe Johnson on 2/9/2000 6:11 PM MST:

: Hi all,

: In update #8 the following is found:

: Drive Assembly Output Screw thread: M10 x 0.1 Right Hand
: Internal locking thread: M5 x 0.8 Left Hand

: Something is not right here. For one thing, the pitch is DEFINITELY wrong, probably a typo. If it is metric, it is an M10 X 1.0 Right Hand thread (not a 0.1 pitch as listed).

: BUT, the thing that I am confused about is that I know I have made adaptor shafts in the past with 3/8 x 24 threads in them. They worked fine for a few years.

: While 3/8 (.375 inches) is close to 10mm (.394 inches), close is not the same.

: Also, while 24 pitch (.042 inches per thread) is close to 1mm pitch (.039 inches per thread) again, they are not the same.

: So… I would be surprised if a 3/8-24 nut would thread easily on an M10 X 1.0 screw.

: In addition, I have not found a Jacobs Chuck (which I believe these drill have on them) that has a metric thread in it.

: Anyway, perhaps Jacobs has gone metric after all, or perhaps Bosch has changed chuck suppliers, or perhaps an M10x1.0 screw accepts a 3/8-24 nut, or perhaps I am a crazy person.

: That is just it… …I don’t know.

: Does anyone else know? If so… do tell.

: Joe J.

Don’t know about Jacobs or Bosch but my Starrett calipers and thread gages say its definitely 3/8’-24 TPI (actually 0.367 in. major dia. and w/in UNS Class 1A tolerances). Like you, we drilled/tapped our coupling hubs to 3/8-24 and they fit fine. I guess if one was a fan of mechanical welding and didn’t expect to remove the extension shaft or coupling you could go with the M10 threads.

As for the crazy part - I can only speak for myself and I blame it on the robot. However, I’ve been like this long before my exposure to FIRST.

By the way Thanks much for the drill tranny mods - they make a world of difference.

Ken Wilson

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