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Ah yes...if you have a VFD/Inverter rated motor... mine is c1998 1.5kW (2hp) 3-phase 1400. it'll run ok at 1600-1700... i wouldnt like to take it to higher than that... so geared up 1:2 it'll give me 3000 - 3500 at the spindle...., maybe a tad more....
all that is some good info guys thanks for all of it :smile:
now i bought some ally plate today is it a good price?
80mm x 247mm x 12mm Aluminium Plate / Sheet 1 £4.75 GBP £4.75 GBP
103mm x 227mm x 10mm Aluminium Plate / Sheet 1 £4.95 GBP £4.95 GBP
125mm x 185mm x 10mm Aluminium Plate / Sheet 1 £4.50 GBP £4.50 GBP
69mm x 481mm x 10mm Aluminium Plate / Sheet 1 £6.50 GBP £6.50 GBP
110mm x 540mm x 6mm Aluminium Plate / Sheet 1 £6.50 GBP £6.50 GBP
Subtotal: £27.20 GBP + £7.06 GBP Postage & Packing
i want to use it to mount the motors on.
I usually reckon anything better for Aluminum than about £7/kg is a good price... that first piece is 0.65kg, so £4.56 would be a good price... overall you got 3.82kg Aly for £27.20, my guide price would have been £26.77. You paid slightly over the odds on the smaller offcuts and did slightly better on the larger ones... overall, not bad.
cheers irving once again :) just wanted some ally to paly with an impulse buy :-)
Where did you get it from?Quote:
Originally Posted by h4ppy-chris
ebay http://stores.ebay.co.uk/The-Bits-And-Pieces-Place
(If purchasing multiple Items request an invoice for combined shipping costs) i saved £12 ;-)
Quote:
Originally Posted by Jonathan
brain has gone west, 3 holes centers at 35mm what is the circumference ?
help an how did you get the answer.
219.91148575128552669238503682957mm ish :)
2 x pi x r
unless iv got the wrong end of the stick
3 holes around a circle 35mm apart if that helps what is the circumference ?
Erm, surely that's just 35*3 = 105mm? I've probably got a different end of the stick...
I get a radius of 20.207.
I'd explain fully, but I'd need to do a drawing.
It involves the constant that all the angles within a triangle add up to 180deg, and a bit trigonometry.
ahh... i get it now, im with m_c on this one 20.07mm radius will intersect 3 points 35mm apart
took me ages to work that out
i can find the formula for 4,5,6 but not for 3 :confused:
Attachment 3529
PCD Calculation Formula
3 stud PCD = S / 0.866
4 Stud PCD = S / 0.7071
5 Stud PCD = S / 0.5278
6 Stud PCD = S / 0.5
3 stud PCD= S/0.866
peter
thanks peter star man, added it to the post :-)
Ahh, now I understand the question! You wanted *diameter* not circumference at stated in your post.
It's just cos(30)...
Let x be side length of the triangle the three points form (i.e 35mm).
(see diagram)
Draw in lines on triangle that bisect the angles. So we've now got a smaller triangle with one side length x/2, and we know the angle indicated is 30 degrees, since it's an equilateral triangle and we've bisected the corner angle.
cos(30)=(X/2)/r
r=X/2/cos(30)
r=17.5/cos(30) = 20.2072594...
(since d=2r, d=X/cos(30))
Incidentally to help remember it cos(30) is just sqrt(3)/2 = 0.866025...
Hope that helps. You can get the other PCDs using similar methods. 4 is half root 2.
thanks jonathan ;-)
Ahh just realised. My method can easily be extended to the general case for n bolts. You just need to know half the angle interior angle of the particular polygon. Then do cosine of that to get the factor...
3 = Triangle, 60/2 = 30, so cos(30)
4 = Square, 90/2 = 45, so cos(45)
5 = pentagon, 108/2 = 54, so cos(54) = 0.5878 (!)
6 = hexagon, 120/2 = 60, so cos(60) = 0.5
The formula to find the interior angle is 180(n-2)/n.
So that means, given n bolts with spacing x.
r=x/(cos(90(n-2)/n))
PCD = x/(2*cos(90(n-2)/n))
enjoy!
like the formulae but...
er where is x used??
x=bolt spacing(centre to centre)
Peter
my question is - none of these formulae use x - I'm sure they should somewhere?!?Quote:
Originally Posted by Jonathan
r= x/(cos(90(n-2)/n))
PCD = x/(2*cos(90(n-2)/n))
should be x/cos(whatever), as you're working out the hypotenuse from the adjacent.
fair do's
I've updated by guesswork...
Yes it is, sorry ... was rushing and missed that :redface:Quote:
Originally Posted by m_c
big time backlash on the z axis so time to investigate and here's what i found.
http://www.youtube.com/watch?v=HhvexSsmMxk
and here's how i sorted it :smile: there was play between the bearings so skimmed 0.76mm of the end cap no more play :smile: backlash now down to 0.003
http://www.youtube.com/watch?v=I8_JhbRmj7Y
well my ally turned up so made a start on the z motor plate :smile:
all i could think of when making it was, if the mill was finished i would just be watching it being cut.
Attachment 3552 Attachment 3551
Similar to how I did it except I mounted the motor plate 90 degrees clockwise to yours, and lathed a bit of 3" aluminum bar to act as a spacer and give a bit more surface area for the motor plate to bolt on to. Doing it that way enables me to use the handle for manual drilling without removing the stepper - I think yours would collide?Quote:
Originally Posted by h4ppy-chris
good point jonathan, i will wait till it's all working then make a new one.
Here's a couple of photos of mine, pretty self explanatory...Quote:
Originally Posted by h4ppy-chris
cheers mate that's give me some think to think about.
how do you get started! i am using autocad then lazycam.
say i have a 10x10 cm x 5mm piece of ally clamped on the mill bed, and want to put a hole in the center.
how do i set mach3 up?
.
1. load in the gcode.
thats as far as i am can you help?
easy way is to cut air to see where its start/reference point is
you will have stipulated this when you drew it up
it may need to be zeroed in on one of the corners of you block or it my start from the dead centre
im guessing it depends on what the default is if you didnt stipulaite this yourself in lazycam
i tend to cut air to kick of with, just run the first couple of lines to make sure youve not made any big mistakes
edit: if you have a look in the tool path window in mach that should give you a clue as to where the tool will start from in comparison to where it will make the first cut
mark the sooner you can come over to my house the better. before my head pops, did you get my text?
no ? er hang on a mo my phone is flat:redface:Quote:
did you get my text?
got it, ill give you a shout later
nice 1, i ordered my x and y motors yesterday :)
Maybe this will helpQuote:
Originally Posted by h4ppy-chris
http://www.mycncuk.com/forums/showth...9965#post19965
Phil
i was thinking the problem was more one of orientation between drawn part and machine bed and material... eg: sussing out the work flow from CAD to CAM to MACH to materialQuote:
Maybe this will help
youll have to let us know chris
I have updated MY post to show the part is drawn in CAD at the lower R/H portion of XY ZeroQuote:
Originally Posted by blackburn mark
It doesn't make any difference in which position you draw it you just put it in the same position in Mach3
Phil
okQuote:
I have updated MY post to show the part is drawn in CAD at the lower R/H portion of XY Zero
It doesn't make any difference in which position you draw it you just put it in the same position in Mach3
i think it might be it a little simpler to stipulate in cam that i was starting from a corner