Search found 193 matches

by choprboy
Sat Sep 08, 2018 3:49 am
Forum: General Discussion
Topic: Can a delta-delta transformer be backfed
Replies: 8
Views: 603

Re: Can a delta-delta transformer be backfed

It depends... and would pretty hard for anyone to give you an answer without more specific information. A delta-wye transformer would generally not be corner grounded on the input (delta) side. The wye side, or basically any output configuration with a derived neutral, would require grounding on the...
by choprboy
Fri Sep 07, 2018 7:38 pm
Forum: General Discussion
Topic: Thru-Hole Tap for 316 SS
Replies: 4
Views: 410

Re: Thru-Hole Tap for 316 SS

For one, a good quality tap is miles ahead of a general hardware store hand tap. The cutting edge should be razor sharp. I like OSG as a manufacturer. Even better, spiral flute taps are amazing, lifting the cuttings right out of the hole as you tap. But spiral flute taps are more fragile than hand o...
by choprboy
Sat Sep 01, 2018 9:26 pm
Forum: General Discussion
Topic: unique water pump
Replies: 55
Views: 3027

Re: unique water pump

The skin effect is negligible up to a few hundred kHz or very large wire sizes. At 60Hz, the skin effect is roughly 8.5mm deep (1/3"), so there is negligible loss in conductor below 17mm (2/3") in diameter.
by choprboy
Fri Jun 22, 2018 9:13 pm
Forum: General Discussion
Topic: not how they teach you to do it in school
Replies: 11
Views: 1768

Re: not how they teach you to do it in school

Better than a spiral point (gun tap), is a spiral flute tap. I do 12mm power taps in the drill chuck of my mill all the time. Takes a bit of experience, but get everything lined up and make sure you have enough quill length for the hole, turn on the motor and let the tap gently drop into the workpie...
by choprboy
Thu May 24, 2018 11:11 pm
Forum: General Discussion
Topic: 4130 chromoly
Replies: 5
Views: 1041

Re: 4130 chromoly

I have turned a bunch of 4140, 1-4" pins/collars/threaded rods, no idea what temper, whatever IMS sells. A bit of brushed on cutting oil, HSS drills and threading/boring tooling, or high speed and carbide inserts. Chips come of hot and can take a bit of fiddling with speeds and feeds to make a clean...
by choprboy
Tue May 22, 2018 2:25 pm
Forum: General Discussion
Topic: OT Using DryGas in alcohol blended gasolene
Replies: 9
Views: 1062

Re: OT Using DryGas in alcohol blended gasolene

The alcohol from the gas pump is ethanol. Dry gas is methanol or isopropyl alcohol. All of those are hygroscopic and readily absorb water into the mix (though some people say ethanol more readily breaks down and releases that water?). Personally... I would side-step and say leaving ethanol-gas in th...
by choprboy
Tue May 22, 2018 2:03 pm
Forum: Lathes
Topic: C0630
Replies: 4
Views: 1060

Re: C0630

I don't understand your question... lathes have threading dials to ensure you re-engage the threading lock on the same position of the lead screw relative to the rotation of the spindle, which varies based on the lead screw/gearing of a particular lathe setup. When cutting a thread that is a fractio...
by choprboy
Tue May 22, 2018 1:31 am
Forum: Lathes
Topic: C0630
Replies: 4
Views: 1060

Re: C0630

No direct information, but have a look at this previous thread and use a web translator on some of the linked Chinese pages: http://www.chaski.org/homemachinist/viewtopic.php?t=102256 In particular I notice that one of the pictures shows what appears to possibly be a small 30-ish tooth gear on the s...
by choprboy
Sun May 20, 2018 2:57 am
Forum: Casting & Foundry Work
Topic: Things they dont tell ya when you start casting. :)
Replies: 23
Views: 2485

Re: Things they dont tell ya when you start casting. :)

2) Is a steel crucible a good option for aluminum? No... Lots of people use it, but unless you need to do something special/oversize/etc., I wouldn't use one repeatedly. Iron actively dissolves in aluminum, meaning you contaminate the charge and erode away the crucible. Additionally, the steel exte...
by choprboy
Thu Apr 19, 2018 11:44 pm
Forum: Buy, Sell, Trade, Wanted, Free!
Topic: WTB: 5C collets and blocks or divider ndexing plates
Replies: 3
Views: 749

Re: WTB: 5C collets and blocks or divider ndexing plates

Yeah, the first couple things are relatively straight forward. I already have a 5C spin indexer, but only a handful of random collets. Several of the things I need to do are a fair bit large though... 24 splines in a ~2" bore of a ~5" flange and 6 notches for a ~3" castellated nut. Easy to divide in...
by choprboy
Thu Apr 19, 2018 2:33 pm
Forum: Buy, Sell, Trade, Wanted, Free!
Topic: WTB: 5C collets and blocks or divider ndexing plates
Replies: 3
Views: 749

WTB: 5C collets and blocks or divider ndexing plates

Looking for a standard set of 5C collets and hex block (dodecagon would be great), no preference on brand. Or some indexing plates I could use to make a custom index fixture. I want to cut some splined shafts and collars, but not exactly sure how I'm going to do it yet. Probably single-point broach ...
by choprboy
Thu Apr 12, 2018 2:48 pm
Forum: Favorite Places to Shop In Your Area
Topic: HGR industrial surplus. Euclid Ohio
Replies: 18
Views: 10355

Re: HGR industrial surplus. Euclid Ohio

I recently tried to buy from HGR after oggling for a few weeks... but I had to cancel the order. They wanted $250 to ship a 100lb chuck across the country. Is this normal? I get a standard crap UPS shipping rates and it only cost about $150 to ship 140lbs in the other direction. You just have to be ...