[hoss2006]

No optical sensor set up yet, I tested RPM's with my tach.
You tell Mach 3 your max RPM per pulley (config>spindle pulleys)
Choose the one you are running at the time, and the C6 board adjusts the voltage based on the Speed chosen in the program (or set in the Spindle box on the main page) to vary the RPM.
Don't know how accurate it all is yet, but will.
I make a little video today perhaps.
Hoss

[Rabies]

Hi all, just noticed this thread, and I have a couple of questions to raise about the automatic drawbar design (both your design and the Z-bot, since they appear to work the same way):

Firstly, if the piston, through the cam, is applying 1000lbs force to the top of the drawbar, doesn't that load get transferred to the spindle bearings at the same time? The Z-bot certainly seems this way, since the cylinder is bolted to the head. It would be kinder to the bearings to arrange the mechanism to push the drawbar out whilst holding the spindle.

And secondly, is it safe to assume that if a rigid drawbar is holding a tool in with a force of 600lbs, then springs to generate the same force will be adequate? Because with a rigid drawbar, if you manage to pull the tool even a little way out then the force required to pull any further will increase very rapidly (thousands of pounds within a few thou, most likely.) With springs, loaded to their recommended deflection at 600lbs, the force required the further the tool is pulled out will only increase a couple of hundred pounds until the washers are completely compressed. So, with a rigid drawbar it may take a few thousand pounds pull on the tool to loosen the collet enough to release the tool; but with the springs it may only need 900lbs, even for an instant, to pull the collet easily far enough out of the taper to release the toolholder.

I have no idea if this is actually the case, but it's what my intuition tells me.

[hoss2006]

I can see your point about stress on the bearings.
May prove to be an issue down the road but a similar force is required to
release the drawbar manually with a mallet.
Depending on how hard you usually wack it, the initial force may be worse than the power drawbar.
maybe a modified extended spindle might be necessary, purpose made for a power drawbar, time will tell.
I assume the company selling the power drawbar for $100's did some R&D on this,
but you know what they say when you ass-u-me.
Hoss

[hoss2006]

don't run out and buy the c6 board from cnc4pc just yet.
gliches are popping up.
changing the motor tuning settings to get the spindle motor to run is affecting the steppers
i.e. pulse width.
have to do a little research.
hoss

[snowshovelbmx]

oh really? I'd like to hear more about that as you find out, I was going to order the board for when my mill is up and running again.

thanks,
chris.

[hoss2006]

i think it's a computer problem, not the cnc4pc board.
i'm bringing up the mills computer to hook everything to instead of an old backup p.c.
have the feeling the problem is in the computers old parallel port.
it's not giving the c6 board enough "juice".
test it today.

[snowshovelbmx]

oh ok thanks for the update, good luck!
chris

[hoss2006]

well that didn't help.
the newer computer apparently has the same problem as most laptops,
not enough juice for the parallel port.
ordering the recommended breakout board from Cnc4pc when they're back in stock.
it's supposed to boost the signal so that should do the trick.
I added a second parallel port to give me some extra outputs that I'll connect the breakout board to.
Use the original for just the Xylotex and limit switches.
I'll get the relays setup for the drawbar and flood coolant pump on the new breakout board along with the Spindle board.

[skullworks]

( Tagged )

Keep up the good work.

[ataxy]

cant wait to see the finished work

[Bob Adams]

This will give you something to look at while Hoss is waiting for parts.
I took Hoss's wisdom and came up with this support bracing and made a pictorial for air circuit.
New DXF.:cheers:

[Oldmanandhistoy]

This will give you something to look at while Hoss is waiting for parts.
I took Hoss's wisdom and came up with this support bracing and made a pictorial for air circuit.
New DXF.:cheers:

Nice job Bob and thanks for sharing.:cheers:

John

[tpworks]

Just a note for you guys,
I prefer dual port cards for Mach it keeps the data rate equal. Just a thought.

http://www.tigerdirect.com/applicati...CMP=OTC-PWATCH

[hoss2006]

This is my power drawbar layout so far.
Have to draw up and dimension the individual parts tomorrow.
Plan to use quick release hitch pins to make replacing the belt easier.
Uses a modified Clevis from McMaster-Carr.
I'll make a color coded drawing later that shows what's aluminum, steel and bronze.
Later Hoss
http://www.hossmachine.com

[hoss2006]

My Prints are done, now to make some parts.
Once the mill is back up and running that is.
Should get the electronics finished up this week.
Pretty pointless to build anything yet if the software can't control
the spindle and drawbar. First things first.
Then on to see if what's on paper works like it should.
May need a tweak here or there.
Here's a color drawing of the drawbar layout.
Hoss

[Willyb]

Hi Hoss

Looks good. What size cylinder are you planning to use? One good thing with this design is you can easily change up to a larger diameter cylinder if required?

Willy

[hoss2006]

Hey Willy,
I have a 1.5 in. Bimba that should put out 194 lbs at 110 PSI.
With the lever, will impart 1164 lbs. on the drawbar.
It only has to move about .010 - .020 to release tests showed.
Hoss

[Bob Adams]

I'm going with Hoss's plan. Keep on trucking Hoss!:cheers: :cheers:

[Willyb]

Hi Hoss

That should work out just fine. Good luck with your project and have fun.

Willy

[hoss2006]

It's alive!:banana:
The C10 Breakout Board from Cnc4pc fixed the second parallel ports low voltage problem.
It now runs the C6 Spindle Control Board at 5 vdc that it needs.
Now I have plenty of pins to hook up limit/home switches and relays for the power drawbar and coolant pump, plus whatever?
The C6 board puts out a max of 10 vdc to run the mills spindles circuit.
I have a replacement circuit board from a treadmill that uses 12 vdc so I don't get the max RPM when running under PC control.
I figure I'll still get 3700 RPM max. I'll live with it.
Arturo recommends a max of 7 vdc for the Sieg x3 circuit, so I image you'd get the full RPM's from the C6 board.
I have a Spindle Control video that shows a preview of how it all works with some Mach 3 setup.
P.S. I made some flanges like these to convert the tool holders I made to be similar to Tormachs.
Hoss