Member postings for John Coates

Right the cobalt drills have arrived so I can drill the broken tap out

Original hole = 5mm

Tap size = M6 x 1.0mm

What size cobalt drill should I use and what RPM should I run it at?

Thanks folks. The sooner you answer the sooner I can get at it.

Oh and will I need coolant? (I don't have a pumped coolant supply btw)

John

Sorry to resurrect this but the acid hasn't worked (been at it three days) so I'm going down the cobalt drill route (set ordered) and need to know what speed to run the drill at. The set I've bought goes up to 6.5mm from 1.5mm in 0.5mm increments so which should I use (original hole was 5mm for the 6mm tap)?

Cheers folks!

John

John

I think I confused things as it wasn't these specific chargers I was thinking of using for the laser alignment project but for the low voltage lighting. I was trying to understand why the voltage I measured was different to the rating printed on each charger. This woud be so I could test other units to find one suitable for the laser.

I think the answers so far have helped me a lot to understand why I am getting the results I am

John

Les

You are quite right about charger no.4 it is rated at 1.25A (just been into a cold garage to check!)

Luckily I am into my second large glass of port so that hardened me up for the journey

Am going to follow it up with a glass of malt in case I have to go in there again! 

Edited By John Coates on 17/02/2012 22:51:43

Edited By John Coates on 17/02/2012 22:52:17

Philip

Thanks for the tip about testing in series. Will try that tomorrow. I have got another 2nd hand battery for my bike but don't want to attach my current battery charger before I know it is good.

John

Hello again gents

I am trying to find a mains powered charger to power some lights and a laser (for the MEW 186 article about centering). I am also trying to establish whether my current motorbike charger is knackered or not. From my collection of chargers old and new I drag them out and set to measuring their outputs with my Gunson UT105 multi meter.

Charger No.1 - Black & Decker cordless drill

In use to charge up my drill so the genuine end fitting is on

Rated output 18.2v DC at 210mA

Measured output 19.6v DC and 8v AC !!!

Charger No.2 old Bosch cordless drill

Cable is removed from charging base unit and measurement taken across the two wires

Rated output 14.5v DC at 250mA

Measured output 18v AC !!

Charger No.3 for my new jump starter (bought last weekend)

In use to charge up the new jump starter so the genuine end fitting is on

Rated output 12v DC at 500mA

Measured output 21v DC

Charger No.4 my motorbike charger

Measured across the crocodile clips

Rated output 12v DC at 1.25mA

Measured output 0.17v DC

So my question is am I measuring these wrong or do the measured values usually differ so much from the ratings on their casings?

Thanks, John

Edited By John Coates on 17/02/2012 21:28:44

Edited By John Coates on 17/02/2012 21:29:10

Surely a search of the back issues of MEW will reveal lots. Unfortunately I am using a Macbook without my MEW index but will look later when I can access my other computer