Search found 868 matches

by John Hasler
Sun Sep 23, 2018 7:10 pm
Forum: General Discussion
Topic: Schematic Symbol questions
Replies: 13
Views: 314

Re: Schematic Symbol questions

Not a standard symbol. Zustellbetrag seems to mean "feed increment", if that's any help. The double tilde usually means "approximately equal".
by John Hasler
Sun Sep 23, 2018 11:29 am
Forum: General Discussion
Topic: Schematic Symbol questions
Replies: 13
Views: 314

Re: Schematic Symbol questions

Might also be a reluctance sensor, in which case it will have a small magnet inside. Could be an inductive sensor. How old is the machine? Do you have a picture of it in place?
by John Hasler
Sat Sep 22, 2018 2:58 pm
Forum: General Discussion
Topic: Gage blocks
Replies: 54
Views: 1661

Re: Gage blocks

Only if they are made of materials with identical coefficients of thermal expansion.
by John Hasler
Sat Sep 22, 2018 10:21 am
Forum: General Discussion
Topic: Metalllurgy question
Replies: 9
Views: 224

Re: Metalllurgy question

Kelly Jones writes: 2024 (and other aluminum alloys) are precipitation hardening. That means given temperature an time, alloying elements will migrate within the metal and form tiny clumps, which strengthen the alloy. Some alloys do this at room temperature. I recall reading of a vendor who shipped ...
by John Hasler
Fri Sep 21, 2018 7:28 am
Forum: The Junk Drawer
Topic: Power for a hoist
Replies: 10
Views: 230

Re: Power for a hoist

Good points. A 120 V universal series motor with no load will turn slowly when connected to 12 VDC. Odds are that the diode blew for a reason and so will just blow again, but replacing it is worth a try. If it is a universal motor it will run on AC. To reverse a series motor you must swap the leads ...
by John Hasler
Thu Sep 20, 2018 10:01 pm
Forum: The Junk Drawer
Topic: Power for a hoist
Replies: 10
Views: 230

Re: Power for a hoist

You should see about the same resistance as an electric drill. Replace the popped diode with one rated at least 10 amps and 250 volts.
by John Hasler
Thu Sep 20, 2018 5:29 pm
Forum: The Junk Drawer
Topic: Power for a hoist
Replies: 10
Views: 230

Re: Power for a hoist

Is there a sizable control circuit between the wall socket and the motor? It would be unpractical and uneconomical to convert 120AC to 12VDC for a motor if a 120V motor could be specified. My guess, not knowing much about, is that the motor is a universal motor, reversible and variable speed like i...
by John Hasler
Sun Sep 16, 2018 3:33 pm
Forum: Lathes
Topic: Lathe setup question(s)
Replies: 19
Views: 371

Re: Lathe setup question(s)

tornitore45 wrote:
Sun Sep 16, 2018 12:44 pm
A lathe bed has to be flat. Leveling is the usual way to achieve that but not the only one.
OK John do not keep us in suspense.
http://www.homews.co.uk/page318.html
by John Hasler
Sun Sep 16, 2018 12:28 pm
Forum: Lathes
Topic: Lathe setup question(s)
Replies: 19
Views: 371

Re: Lathe setup question(s)

A lathe bed has to be flat. Leveling is the usual way to achieve that but not the only one.
by John Hasler
Sun Sep 16, 2018 11:59 am
Forum: General Discussion
Topic: WTF is wrong with shipping to Canada???!!!
Replies: 25
Views: 759

Re: WTF is wrong with shipping to Canada???!!!

I'm quite certain that exporting copper tube does not require an ITAR license.

It's possible that McMaster does sell stuff that would require a license and rather than go through their catalog and figure out which things can be exported and which can't they've taken the easy way out.
by John Hasler
Sun Sep 16, 2018 8:41 am
Forum: General Discussion
Topic: spot drill angles
Replies: 8
Views: 277

Re: spot drill angles

Just use center drills. They work fine.
by John Hasler
Sun Sep 16, 2018 8:39 am
Forum: Lathes
Topic: Lathe setup question(s)
Replies: 19
Views: 371

Re: Lathe setup question(s)

Note that horizontal alignment error is much more important than vertical. If the far end of your bar is .001" closer to the toolpost than it is near the chuck then you are going to get a diameter .002" smaller out there. If the far end of the bar is .001" higher than it is up by the chuck then a to...