Messages

131

General Mach Discussion / Re: Muti-start threading....

« on: April 01, 2009, 10:22:15 AM »

Yes that's what I was doing, it was actually a tool with 4 flutes and a single point in profile, if you get what I mean.

Great thing about single point is you can use the same cutter for any pitch as long as it cuts deep enough, I have a small one for around 3 -10mm and a larger one that can cut to about 4mm deep so quite large threads.

Steve

132

General Mach Discussion / Re: Muti-start threading....

« on: April 01, 2009, 05:31:17 AM »

Maybe not Andy, As I said I've never used G76 as I was using a mill to do the thread.
I literally just lowered the knee by the required amount without altering the code, quick and dirty but it got the job done.
I had to do this because I was making a small steam engine and I tapped the cast Iron valve block for the gland nut M6 fine then threaded the nut with the M6 fine die only to find the tap was M6X1.5 twin start so I had a machined casting with the wrong thread.
My solution was to make a new nut with the twin start thread to fit and it worked brilliantly, my first milled thread and a twin start to boot.

Moral of the story, don't assume the cheap tap and die set you bought 15 years ago has the right threads in it M6X1.5 twin start looks very much like M6X0.75 so they must have got them mixed up in the factory!

133

General Mach Discussion / Re: Muti-start threading....

« on: April 01, 2009, 04:56:03 AM »

Hi

I've done multi start threads on my mill using the same principle, just move the start up or down the Z by the required amount, only down side is that on a mill it finishes short by that amount too so you end up with each thread finishing short by the offset.
There are a few solutions that come to mind but they all involve a bit of hand coding which i try to avoid as I nearly always make a silly small mistake.

Steve

134

General Mach Discussion / Re: Motor tuning calculations

« on: March 29, 2009, 11:42:59 AM »

Make sure your acceleration is very low to start with, this will stop you losing steps and giving you a false reading.
With half step and a 10 tpi lead screw you should have 4000 units per inch (unit) so as Ray said it looks like your not running half step.
Also check your lead screw, if it's a 5 tpi twin start it'll look like a 10 tpi. To check this turn the screw 1 turn by hand and measure the movement.
Sorry if this is all obvious to you but I thought it's worth mentioning.

Steve

135

General Mach Discussion / Re: Software to convert Dxf to Gcode, aka CAM. Recommendations wanted

« on: January 10, 2009, 11:16:34 AM »

Second go at posting.

I use Sheetcam aminly, I've also used Cambam but not tried Cut2D.
For 3D I use Meshcam.
You'll find most common jobs use 2.5D.

Steve

136

General Mach Discussion / Re: cat 5

« on: December 21, 2008, 05:29:53 PM »

I try to use the stranded Cat5 for network cables but sometimes have toget the solid stuff.
I was having a problem getting full speed on a 100mbps network and found that the pairs were connected randomly, this meant the signal noise was interfiaring with the signal.
Also it's been found that very high frequencies travel on the outer area of the wire so small niks and cracks stop the signal.
Not entirly relavent to CNC but just thought it may help some one in the future.

Steve (on the second bottle of wine)

137

LazyTurn / Re: LazyTurn

« on: December 10, 2008, 06:52:29 PM »

A lot of users like to think their machine is more accurate than it actually is, but there are a few that do seem to have very accurate small machines.
I would think that as far as the software goes it shouldn't mind working with tight tolarances as it's based around maths so you should be able to work with very small numbers.

While I'll be very happy to have my mill machine to within 0.01mm one day I don't think it's asking a decent lathe too much to do that normally.

Steve

138

General Mach Discussion / Re: How to set "Safe Z"?

« on: December 08, 2008, 03:18:33 PM »

I've always wondered how it worked, not been bothered enough to look into it deeply but nice to have my suspicions confirmed.
I did think it was in reference to work coordinates so I set mine to +5mm, no wonder it went AWOL when I tried a run from here, so I did think I'll have to check but never got round to it.

Just read that back to myself and it sounds kind of weird, not going to write it again though

Steve

139

General Mach Discussion / Re: computer causing gorilla cnc glitch

« on: November 29, 2008, 01:29:08 PM »

I'll also add that I've used my mach 3 controller several times with 3D files that have taken 8-9 hours on a medium sized mill cutting Brass and Aluminium at 300mm/min and Mach has never failed mid file.

Steve

140

General Mach Discussion / Re: computer causing gorilla cnc glitch

« on: November 29, 2008, 05:36:44 AM »

As you've found out this is a problem with booting a computer while your machine is on, the post and OS send signals to the PP, so as has been said use a charge pump, this will stop that happening.
I will add though that you should be using a UPS on your control computer, this will help with most computer problems and is a must when controlling expensive equipment.

Steve