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Member postings for jason udall

Here is a list of all the postings jason udall has made in our forums. Click on a thread name to jump to the thread.

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Thread: Imperial fractions on drawings.
02/04/2014 20:45:09
Don't know about old hand. But
Are dimensions in this format the norm..
Sorry . There is no norm.

I too find fractions a pain.. ( not the maths but the umteen umteenth bit)
What I do is go over the drawing and mark up in units as required... inches mm cubits whatever but as decimals
.then in the case of some older drawings also convert the drill number sizes. .gauge etc.

Your next problems will be fits .. again almost never marked on drawings but refer to the text for guidance....

Good luck
Thread: Modifying stepper motor shafts
02/04/2014 19:48:14
A thought.
Have a care with the wires of the stepper...
The motor will (if a hybrid stepper)..generate quite large voltages...
Don't short them as this will cause the motor body try to turn with shaft
..ideally add resistors..or low wattage light bulbs ..or better still neons .. "shorting" the coils. .the motor will still try to turn with the shaft but the voltage won't get chance to flash over the coils.
Well that's what I would do..
Thread: Cutting a hole in Cast Iron
01/04/2014 16:27:36
If you can work rigid lose the pilot drill..often go blunt "early"..and stall the process
Thread: Plastic v bronze bushes/bearings
31/03/2014 12:14:26
Just so...
Igus used to recommend ground hard anodised ( not certain from memory?weather ground then anodised or ground after anodising) ali shafts...for longevity and friction. .but ss idealy ground would be good ( and not unconventional)
Are you talking turned from bar or moulded bushes. .again years ago igus weren't keen on one
Machining your own.. ( they used to be very "protective" of their products reputation)..
Good luck..
Thread: end mill speeds
31/03/2014 12:05:53
Mike.. I was referring to the Surface speed..yes in feed rate and depth of cut are effected by tooth count.
And yes 70 fpm is probably very conservative. .
..
Thread: Die Head Advice
31/03/2014 10:18:41
Die boxes are great..thread rolls are fantastic...
The resultant ( rolled ) thread is beautiful and the whole process ( once set) like magic ( both processes. .)
But then I am biased.
Enjoy your die box..
Thread: end mill speeds
31/03/2014 10:11:23
Lets try...say 70 feet/min
2" cutter
Above we get 133 rpm.

10 ,000/(50.8)= 196 rpm

Working through from70 f p m would give 6790 /dia
In any case there is a constant that from taste/experience gives a finish you desire and once established a simple divide by cutter diameter will yield an rpm you probably don't have anyway...
Don't get hung up on number of flutes...that only effects depth of cut not spindle speed
31/03/2014 09:54:11
Too lazy this morning..how far out would 10, 000 rpm /dia (mm) be?
Thread: Plastic v bronze bushes/bearings
31/03/2014 09:50:52
Btw as to keeping with the design...ball bearing races would be an excellent functional replacement. .but authentic ...?....
31/03/2014 09:48:32
Igus plastic is superb.
Note the housing sizes are designed to "squease" the plastic a little. .
So selection of shaft bearing housing sizes is specific to the material .
Igus also favour s low surface speeds ( phenomenonal endurance but low speed)..so as wheel bearings ..maybe not..see data sheets...
...also performance under pressure( say again wheels support loads) is much lower than bronze....the shaft will tend to press through in the direction of the load. ...again not poor but not bronze....


As to realism. ..well you are building a model of a steam locomotive ....maybe authenticity is more important than function. ....but it is your model.
Thread: colouring steel
29/03/2014 15:45:41
Aye
29/03/2014 10:30:16
Can I suggest a fine polish with degrease/iron wool...and turn back...seems to work for me all to frequently
Thread: Rules or Rulers
29/03/2014 10:27:57
And apparently Han Solo can do the kessel run in only 12 parsecs
29/03/2014 10:25:15
Cables?
27/03/2014 23:32:26
Slide rule...mmm
The only slide rule I still keep is rotary....
Thread: What's wrong with T nuts? (compared to T Bolts)
27/03/2014 21:06:07
I take from this. Don't allow your bolts/studs to bottom in the tee slot.
Don't leave scarf/chips between mating sufaces when clamping
Avoid unsupported pulls on table..where clamp or stock help prevent pull out.

Let me add...tee nut bar...over long with regard to normal tee nuts..spread any loads over more tee slot....

Thread: Rules or Rulers
27/03/2014 20:58:33
Scale or scales?
Thread: What's wrong with T nuts? (compared to T Bolts)
27/03/2014 13:22:33
Added to that
.in the jacking situation
1 all that force doesn't improve clamping..
2 when ADDED to the pull from above means a stud that couldn't break the slot alone sees potentially double that force which might exceed the slots yield strength.
27/03/2014 13:11:30
Richardandtracy...
I too have not seen seperate moduli listed.
But the "geometry" remains the ctitical difference. .shorter element below thus less "squishy" than the say ten times longer element in tension "hooke law"..
27/03/2014 10:14:45
What I am trying to say is..the give is the stud in tension is much larger than in compression. .thus "feel" is much less forgiving in the jack situation than the pull
<< First < Prev 37 38 39 40 41 42 43 44 45 46 47 Next > Last >>
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