Quick Question Thread

[Dr Stan]

(02-22-2019, 11:36 PM)Clifford B. Wrote: Hey Doc. do you remember the 3M system ??
It went hand in hand with the PMS.
MRFA C.Brewer USS Ajax     79-81

Yep.  That's how I became familiar with Preventative Maintenance.  All the machines had laminated cards with instructions for daily, weekly, monthly, quarterly, semi-annual & annual PM's.

That also brings up a funny story.  Had this PB3 (Push Button 3rd.  Was given E-4 for enlisting for an additional 2 years, total of 6) who couldn't find his a$$ with both hands.  Also an arrogant little snot.  About 30 days after reporting aboard had pissed off everyone in the 50 man shop.

Well said PB3 had a PM that included taking a hydraulic oil sample from a turret lathe.  He couldn't be bothered with getting the machine manual in the shop office so he came up with his own idea.  Went down to the galley and got an empty #10 can and unscrewed a pressure gauge.  Word quickly passed through the shop and we gathered watching his actions.  He held the can in front of the manifold that normally held the gauge with one hand and turned on the lathe with the other.  A solid stream of oil shot out of the hole, knocked the can out of his hand, showered him with oil and made one hell of a mess all over the deck, etc.  You should have seen us laughing.  Too bad YouTube wasn't a thing then.  Ditto for America's Funniest Home Videos.

Well we made him clean up his mess before we allowed him to go and shower and change his uniform.  He did become a little more human after that.  He also caught a dose of scabies in Taiwan and had to wash everything he owned plus his bedding.

[Highpower]

(02-23-2019, 11:02 AM)Dr Stan Wrote: Well said PB3 had a PM that included taking a hydraulic oil sample from a turret lathe.  He couldn't be bothered with getting the machine manual in the shop office so he came up with his own idea.  Went down to the galley and got an empty #10 can and unscrewed a pressure gauge.  Word quickly passed through the shop and we gathered watching his actions.  He held the can in front of the manifold that normally held the gauge with one hand and turned on the lathe with the other.  A solid stream of oil shot out of the hole, knocked the can out of his hand, showered him with oil and made one hell of a mess all over the deck, etc. 

I remember having to stand on an 8 foot step ladder to get at the oil fill access panels on C9-A aircraft. We had to take oil samples from each jet engine after every 3rd flight completed. This was done "old school" by siphoning the oil out via a clear plastic tube that was snaked down into the oil fill port, in order to fill a small oil sample bottle. Oil samples had to be taken within 30 minutes of the aircraft's landing, so the particulates were still dispersed in the oil.

Nothing like standing at the top of a ladder with a mouthful of steaming hot Mobil Jet-1 engine oil while trying to start a siphon to begin (or end) your day. Thanks for the memory Stan.

[chucketn]

I have a quick question. I'm building a Cracker steam loco, and need to solder the brass axle/crank bushings into the .069" thick steel side frames. Will this solder from Lowe's do the job with a maps gas torch?

https://www.lowes.com/pd/Worthington-4-o...er/3817961

[TomG]

It's a 6% silver solder and melts at 430ºF, so it should work fine with MAPP gas, as long as the plates/parts are not too large.

Tom

[Dr Stan]

(02-23-2019, 11:55 AM)Highpower Wrote: Thanks for the memory Stan.  

Well at least we can tell the frat boys about real drinking.  Ya know you've had enough when you were out with some Aussie sailors  and headed back to the ship and you see not one, but two aircraft carriers tied up to the pier.

[chucketn]

I can vouch for the Ausie and Kiwi Air Force as well. Remember some good times involing copious quantities of Foster's at the NCO Mess at RAAF Amberly during the Kangaroo III exercise...

[Pete O]

Here's another quick question; what is a reasonable depth per pass, cutting a slot with a 10mm 3-flute carbide endmill at 850RPM in 4140? I'm cutting the vertical part of the circular T-slot (see my frankenmill project thread), the carbide endmill is cutting like a beast but I've only been brave enough to go .150" per pass. Got to go to 1" deep and each pass is taking 45 minutes. 5 hours of cutting at the present rate. How deep could I get away with per pass to speed the process up?

[TomG]

Hey Pete,

First of all, your rpm is way too low. A carbide end mill running in 4140 should be up around 4000 rpm. I generally use a depth of cut of about 1/8 the diameter of the end mill, or about .05" for your application. A shallow cut at a higher feedrate is much easier on end mills than a deep cut at a slower feedrate. You can go deeper if the end mill is exposed, but in a slot like that, shallow depths allow the chips to clear better.

The formula I use for rpm using HSS is 4 x cutting speed in surface feet per minute divided by the diameter of the tool (or work for turning). Carbide can be run at least 4 times as fast.

Tom

[Pete O]

The vertical attachment on the U2 has a maximum speed of about 1200RPM or so and the machine just does not feel happy at that speed so I generally limit it to the next highest which is 850RPM. Once the J-head is mounted I'll be able to get some proper RPM but I'm limited to what the old girl will do at present. One more reason why I need to get this project done! I'll use a shallower DOC and crank the table around faster.
Will the carbide endmill have a disadvantage compared to HSS at the slow RPM I'm limited to?

[TomG]

No disadvantage, but no advantage either. If you can only go 850, the carbide isn't doing anything for you other than waiting to snap off due to the high chip load (from the low rpm). HSS would be the better option because it's flexible and pretty happy at that rpm.

Tom