Search found 1100 matches

by John Hasler
Tue Feb 19, 2019 11:58 pm
Forum: Riding Scale Railroading
Topic: Train detector, welded rails - ideas???
Replies: 14
Views: 804

Re: Train detector, welded rails - ideas???

The "car detector" I mentioned is the same as a traffic signal loop detector. BTW the PLCs I have had experience with are far from delicate. I think they are too pricey for this application, though. Multiple LED-phototransistor pairs could be wired with all the LEDs in series and all the phototransi...
by John Hasler
Tue Feb 19, 2019 7:39 pm
Forum: Riding Scale Railroading
Topic: Train detector, welded rails - ideas???
Replies: 14
Views: 804

Re: Train detector, welded rails - ideas???

Looking for inductance change should work but I think you want the axis of your coil vertical. When a train is present part of the flux path that is normally entirely through air will be through iron. You might be able to modify a metal detector. A car detector of the sort used at parking lot entran...
by John Hasler
Tue Feb 19, 2019 9:04 am
Forum: General Discussion
Topic: Softjaw question
Replies: 15
Views: 1206

Re: Softjaw question

Ok, I'm sure this is going to be a stupid question but I'm drawing a blank, so here goes. A job requiring softjaws is about to commence. I have softjaws and a spider but how does one measure the diameter of the softjaw cut. All of my micrometers measure at 180 degrees whether they be calipers or mi...
by John Hasler
Sun Feb 17, 2019 2:15 pm
Forum: Welding
Topic: Spot welding voltage & current
Replies: 2
Views: 279

Re: Spot welding voltage & current

Spot welders are quite different from arc welders. They rely on resistance heating in the parts being welded rather than on arc heating. This requires that you firmly clamp low-resistance contacts directly at the spot where you want the weld. The open circuit voltages are quite low (on the order of ...
by John Hasler
Fri Feb 15, 2019 8:47 pm
Forum: Lathes
Topic: Spindle Frequency?
Replies: 1
Views: 355

Re: Spindle Frequency?

We need to know more about your setup.
by John Hasler
Thu Feb 14, 2019 10:06 pm
Forum: Milling Machines
Topic: Round Ram Upgrade
Replies: 36
Views: 2424

Re: Round Ram Upgrade

Depends on what you mean by a "true" rotary converter. Driving a synchonous three-phase generator with a DC motor controlled so as to keep the frequency correct would give you perfect separately-derived power. Converters built using a single three-phase motor, some capacitors, and some relays can wo...
by John Hasler
Wed Feb 13, 2019 11:53 am
Forum: Milling Machines
Topic: Round Ram Upgrade
Replies: 36
Views: 2424

Re: Round Ram Upgrade

A rotary converter provides pretty good corner-grounded three phase.
by John Hasler
Tue Feb 12, 2019 2:37 pm
Forum: The Junk Drawer
Topic: Is there a Civil Engineer in the house?
Replies: 20
Views: 1288

Re: Is there a Civil Engineer in the house?

Organized crime not really being very well organized being pedantic about such regional slang as "The Outfit" or "The Mob" is a joke. Which is how I intended my remark.

> Next someone will claim that biscuity glop they serve in Chicago is pizza.

Won't be me. Open-face pot pie.
by John Hasler
Tue Feb 12, 2019 1:36 pm
Forum: The Junk Drawer
Topic: Is there a Civil Engineer in the house?
Replies: 20
Views: 1288

Re: Is there a Civil Engineer in the house?

The construction companies belonged to two different Mafia families, and they didn't communicate well. The concrete is also problematic because it's full of dead guys named Vinnie. Mob, not Mafia. It's in Chicago. Plausible explanation: Due to some oversight such as a failure to read some Federal r...
by John Hasler
Sun Feb 10, 2019 2:13 pm
Forum: General Discussion
Topic: finding steel
Replies: 10
Views: 801

Re: finding steel

I've also been very satisfied with Speedy Metals. Since they are just on the other side of Wisconsin from me I can get 2nd day delivery from them via Spee-Dee Delivery (you have to place the order by phone and request Speed-Dee) for about half of what UPS would charge for their regular ground rate. ...
by John Hasler
Wed Feb 06, 2019 9:10 am
Forum: General Discussion
Topic: Bandsaw tires
Replies: 25
Views: 1987

Re: Bandsaw tires

Steve writes: First think I thought when I saw it was the brush on the rubber band of a VanDeGraff generator. I can picture my hair standing on end while running the saw. Can't happen. The brush touches the steel blade which is conductive and so won't carry a static charge and the blade is also elec...
by John Hasler
Sat Feb 02, 2019 11:10 pm
Forum: Live Steam
Topic: silver soldering steel to steel
Replies: 34
Views: 3628

Re: silver soldering steel to steel

There are air-hardening alloys, though most are water or oil hardening. Silver brazing shouldn't get the steel hot enough to harden, though.