Fingers crossed it'll cut ally

[blackburn mark]

You could stick a sheet of whatever plastic you're using down to the bed and mill slots/holes for the air

iv considered it for long runs, might be a pain to get the holes routed to each o-ring if its a complex pattern

the problem with mixing diffrent size o-rings is the diffrent surface arias would compress the o-rings diffrent amounts

With a sufficiently big syringe how many pads do you think could be served? Or are you sucking the air out of one at a time and swapping the syringe round?

im going to try using one syringe and fix one of the one way valves as an exsaust so you could pull the initial vacuum the pad valves will hold the vacuum ill press the syringe home and the air iv removed from the pads will be routed through the exsaust one way valve ?????? if you can get your head around that :)

i need to do a drawing to show you what i mean.... imagine you have two one way valves attached to the end of the syringe, youll work it out :)

am i sending you a large syringe ? (iv got a few from work)

[Jonathan]

imagine you have two one way valves attached to the end of the syringe, youll work it out :)

am i sending you a large syringe ? (iv got a few from work)

Oh, two valves ... you're using the syringe as a pump!
If you could send me a syringe that would be great, I've not got any that seal any more - found out they don't like concentrated sulfuric acid. I can papal you something for it.

I had better buy some valves and tube. What diameter are you using?

[blackburn mark]

I can papal you something for it.

dont worry about it man, work was scrapping old stock so i didnt pay anything myself :)

found out they don't like concentrated sulfuric acid

they dont like WD40 either

i didnt manage to get much of the surgical tubing, i need to buy some more myself, it looks like 1.5 or 2mm ID and the brass tubing is 3mm
i just used what i had lying around, if i was buying id go for the smallest diameter i could get

Ps: the only reason you would need to use the syringe like a pump is if it failed to seal on the first draw, it would save you having to remove the syringe and start again, im pretty sure you could pull a pretty good vacuum on 4 double sided pads all in one stroke
the 30mm pad held onto a un-polished block of alli for hours without the need for a top up, id top up every now and again if it was on the cnc though :)

[blackburn mark]

I'm looking at the servo controller now. I've traced the PCB and drawn circuit diagram of the interesting bits. The problem is the one you sent me has one significant difference to yours - mine gets 3.3v for the microcontroller and potentiometer via a 3.3v voltage regulator. I think yours is either a 5v microcontroller, or they're getting 3.3v via a voltage divider....

Could you measure the maximum voltage from between R32 and ground on the PCB please? I may have asked you to do that already, this thread is so long I'm not sure!
Also what resistance is your potentiometer - it says on the metal case (FB5k ... i.e 5k ohms for mine)?

Edit: don't worry about the voltage, post #90! Except was that definitely the voltage from the resistor to ground, not across the resistor?

ill try to get another the same as yours
this thread is getting a bit long i guess i should have split it up into spindles router and vacuum stuff

[Jonathan]

ill try to get another the same as yours
this thread is getting a bit long i guess i should have split it up into spindles router and vacuum stuff

Wait a second. I can just make you one using a PIC ... it'll save you buying one and you won't have to modify it.

If you just measure the voltage at the point I said earlier. Remove that resistor (R32), remove R31 and connect the parallel port pin to where R31 connected to the potentiometer, then set spindle in mach3 to highest, adjust the pot so you get the same voltage as measured at R32 earlier. Put R32 back in place and do not move the potentiometer ever again otherwise the microcontroller will probably break.

Measure that voltage, if it's ok then I'll scribble a diagram over the picture you posted.

It would be good if a moderator could split this thread up to save duplication? If not then I'll start a new one about the spindles.

[blackburn mark]

Wait a second. I can just make you one using a PIC ... it'll save you buying one and you won't have to modify it.

If you just measure the voltage at the point I said earlier. Remove that resistor (R32), remove R31 and connect the parallel port pin to where R31 connected to the potentiometer, then set spindle in mach3 to highest, adjust the pot so you get the same voltage as measured at R32 earlier. Put R32 back in place and do not move the potentiometer ever again otherwise the microcontroller will probably break.

Measure that voltage, if it's ok then I'll scribble a diagram over the picture you posted.

It would be good if a moderator could split this thread up to save duplication? If not then I'll start a new one about the spindles.

great stuff, ill get on it as soon as i have time :)
ill probably buy another servo controller so i can run the spindles without mach and for a backup in case i fry the one iv got

[ptjw7uk]

Just a note to say that the different size O-rings should all compress the same amount as long as they are all the of the same thickness, therein lies the problem getting the same thickness in different diameters.

Peter

[blackburn mark]

Just a note to say that the different size O-rings should all compress the same amount as long as they are all the of the same thickness, therein lies the problem getting the same thickness in different diameters.

sounds to good to be true, ill have to do some maths, iv got plenty of o-rings from 18mm ID to 50mm ID and they are all 3.5mm section

[ptjw7uk]

Your right it is to good to be true, must have been asleeop when I did the calcs!!

Peter

[blackburn mark]

Your right it is to good to be true, must have been asleeop when I did the calcs!!

Darn it ! never mind, it would have been nice :)