my build from the start

[irving2008]

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....

[h4ppy-chris]

all that is some good info guys thanks for all of it

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.

[irving2008]

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.

[h4ppy-chris]

cheers irving once again :) just wanted some ally to paly with an impulse buy :-)

[Jonathan]

cheers irving once again :) just wanted some ally to paly with an impulse buy :-)

Where did you get it from?

[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 ;-)

Where did you get it from?

[h4ppy-chris]

brain has gone west, 3 holes centers at 35mm what is the circumference ?
help an how did you get the answer.

[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!

[mmcp42]

like the formulae but...
er where is x used??

[mmcp42]

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=cos(90(n-2)/n)
PCD = 2*cos(90(n-2)/n)

enjoy!

my question is - none of these formulae use x - I'm sure they should somewhere?!?

r= x/(cos(90(n-2)/n))
PCD = x/(2*cos(90(n-2)/n))