Member postings for jason udall

I second what JasonB says ( just to confuse things..) solid carbide.. does not like flexing. it does not even like a miss alingned "center pop"..try 0.3 mm drills at 36,000 rpm if you don't believe me..( 10 /1000" etched centers)....funny still drill moderately well when broken .. just not to depth..

seriously if using hand drill you have been lucky ( or very skillful) to have any success with carbide ..and cordless..ROLLS EYS...WOW..

with hand drill then ...HSS and if metal thin enough consider center drill .. other wise pillar drill ..

Oh Did I mention saftey specs?

I worry more about daylight through jaws..

pair only out lasts about 2 batteries in workshop..

mind you thats about 4 years constant production use....Cant grumble..calipers are almost disposable......mikes last about 6 years with careful use and rotation...screws wear yer know..

now have 3 mikes unfit for use but couldn't skip em...so in a draw at home they go

Steve Garnett....How do you arrive at 2kW?

2kW ...just an (unhelpful it seams) example.

Welll....looks like view on left of main view is wrong...but the point is correct....A knoledge of the system in use is as much a part of the drawing as any view.

Now try and complete the side view of the following

Edited By jason udall on 19/09/2012 23:37:49

re stainless rebar Wellll... Its non magnetic, shiney, not monel.. not ali ...hard.... grinds with white sparks ( never quite got the hang of hss /carbon steel/ ms id from gringing sparks... ) being used in a retaining "pier"/ "pile" in concrete.. with ss ( again I have checked) wire lacing...

have to say I have always seen "rusty" rebar before ( yes something to do with concrete chemistry) but this was shiney so I scrounged some ends ( 18" bits) " might come in for some thing"..

NASTY TO TURN "nobbles" are awfully tough...

Steve. eff. in this case only helps us determine guess the available power to power the grinding wheel wrt. input power ( again "estimated" from V and I   ie 2 kW in 70 % eff means 1400 Watts say

conversly the question " will my converter power this under load? " which was probably the original point ( I forget now) is still mostly un answered by this disscusion..any one care to start a thread for this ? .

intresting though this is I think its done to death in this thread .

OVER

Thinsulate block?

cast yer own,,  perlelite, kaloin and cement mix?

Edited By jason udall on 19/09/2012 11:40:58

Motor eff. is zero at stall ( max torque min rpm) and also zero at "no load rpm". ( max rpm min torque)

max eff. is where the product of these two is max. ( for pm dc motors half max rpm serves as first order approximation) for induction motors ( from memory ) synchronisation equates to max rpm (unloaded) where no power is absorbed into mechanical load..so heres the point.. fan and bearings constitute mechaical loads and cannot be met with zero slip... I forget how to convert slip into watts but there will be a small but non zero load on the motor thus the rpm is not the off load rpm..

where all that leads the OP I don't know. apart from if the wheel cuts with no significant rpm drop then there is adequate power.

bumps? uk stuff has pattern that takes a kind of "loose" nut for pretestioning if required...even found some stainless re enforcing bar..as I heard once "hard as woodpecker lips"...

Ian I would hardly call rebar junk.. probally hitensile and close spec.. material..

But I know what you mean..on our home machines it turns how it turns..and tables of machinability and feeds 'n' speeds are a guide only ( 10 000 rpm /diameter still works for me as starting point)..

lables on photo interuptor..

my guess

0 e+..........0 (unlabled)

0 d+ .........0 ( unlabled)

e+ positive supply to emmitter diode from 150 ohm to +ve supply

.( other one negative to 0V common to screen)

d+ is detector ( to junction of 2k2 and 10k resistors leading to base of tr1)

last pin common to screen

hope that helps

Edited By jason udall on 18/09/2012 13:03:38

Ditto I had planned to post that same l;ink.. . best most graphic "mnemonic" I have seen...GUYs ( and gals) you realy should bother to watch that one... not least for the " model" subject...

At the end of the day 1st 3rd or something freerange doesn't matter..IS IT CLEAR does.

most of the drawings I meet at work from very professional companies could be drawn to no standard at all.. but "work". some "small conpany " drawings are beauliful and complete .

and some times ( my personal pet hate) we get sent a part and say 1000 of them please....

a drawing is often just a place to hang dimentions and if it fulfils this role all is well.

PEACE

As to a bom or shopping list..for a designer (shudders as image of pony tailed "creative" comes to mind) or "author" of a design , to be able to specify the materials list. he or she would need to make assumptions about the customers work holding requirements/limitations..

I see shopping lists for electronic projects almost always but in ME field it is not quite the same...lengths could only be minimums .

I can see both sides of this.

I actually find the process to be rewarding and part of the anticipation prior to the metal chopping proper...all part of the fun..just my experience...

Maybe "beginers" projects have a GUIDE list?

Regards

In short Wolfie you are not alone.

Another "symbol" oftern appearing on drawings..."IF IN DOUBT ASK".

Brilliant In 35 years never seen better explanation.

Never been thoughly convinced by this symbol

hollow cup or truncated cone or lampshade or fez...

I guess thats the point...

cup ..... would show wall on one end and an id on other

fez .... likewisewith wall at other end

lampshade ..id seen at both ends

thus we are left with truncated cone..

one system shows "side elevation" the side you would see it from

the other shows the "projected" view on the far side

As to first ,second ,third and fourth these refer to the quadrant represented by the drawing of a 3d object projected onto three othogonal planes ; both 2nd and 4th are "valid" but unused ( we seem to have enough fun with the other two )

1st angle uses plan under elevation and side elevation the farside you are looking from,

(projection "puhes" )

3rd angle uses plan over elevation(eek) and side elevation the side you are looking from

(views from)

THATS WHY IT IS SPECIFIED...It has wide effects on the interpretation of the drawing.

Why not in words? well the symbol is quicker ( pre cad) to draw than letter" 1ST ANGLE " and provides a cue.

Hth

Edited By jason udall on 17/09/2012 00:01:05

Or bearings {mechanical ) or iron or eddy or I squared R (eletrical)

Edited By jason udall on 16/09/2012 23:21:42

I am with Norman on "off topic" , as being oftern intresting despite off topic..

the "problem" comes in finding these intresting posts when the subject is unrelated

...

For example not esp. intrested in loco's but find techniques and methods employed of intrest...I find I try to read all latest posts ...incase..

Slot drill?