Messages

7711

Show"N"Tell ( Your Machines) / Re: CNC watch lathe

« on: March 10, 2009, 10:10:56 AM »

Nice work Vince.

Tweakie.

7712

Show"N"Tell ( What you have made with your CNC machine.) / Re: Building a 4th Axis from scratch.

« on: March 10, 2009, 10:00:29 AM »

I haven't the faintest idea how to set up Mach to drive a fourth axis yet. There are plenty of posts on this subject (i've checked already) so I will have to do a lot of reading before I can make anything.

Tweakie.

7713

Show"N"Tell ( What you have made with your CNC machine.) / Re: Building a 4th Axis from scratch.

« on: March 10, 2009, 09:23:33 AM »

Just finished making the stepper motor mounting this morning - can't wait to try it out but I have to do a bit more electronics to extend my driver card to include a fourth axis driver.
Fortunately, I have a stepper test rig so I can run it on the bench just to make sure there are no tight spots and that the stepper has enough torque.

Here are a couple more pictures.

Tweakie.

7714

General Mach Discussion / Re: Newbie needs help

« on: March 10, 2009, 09:12:15 AM »

Gerald,

Please don't forget to post some pictures of the stuff you make.

Tweakie.

7715

Tangent Corner / Re: Metal shredder

« on: March 10, 2009, 04:02:29 AM »

In the UK they call these machines fragmentation plants. They usually have 4 hammers (which are bell shaped in section) which are free to pivot within a central hub which is rotated by a motor (big motor). Underneath the hammer assembly is a grille of about 100mm mesh and everything that is placed in the hopper above gets smashed by the hammers until it drops through the grille.

The machines are usually conveyor belt fed from grab cranes and everything that goes in (cars that have been previously crushed into blocks - scrap etc.) comes out as scrolls of gray metal witch all looks exactly the same. Quite an amazing sight.

Tweakie.

7716

Show"N"Tell ( What you have made with your CNC machine.) / Re: Building a 4th Axis from scratch.

« on: March 10, 2009, 03:45:17 AM »

Hi Folks,

My approach to cutting the gear wheel was nowhere near as technical as it should have been. I already had a 60 tooth spur gear so I knew in advance the diameter the finished gear was to be cut to. I machined 60 slots around the circumference of the blank (for the tap to engage) and went for it like it was a knurling operation on a lathe. The initial problem is that the number of teeth versus the circumference did not match because I did not machine the blank to the finished shape )=(   it was initially too large in diameter at the point where the tap first touches (difficult to explain but I hope you understand). So there was some argument between the tap and the blank but this subsided to harmony when the diameter and pitch became correct.

As with all things, if I was doing it again I would probably do it a different way but the way it was done worked. I have since seen examples of this type of gear which has been cut radially into two discs which are spring loaded against each other as a way of eliminating backlash.

Tweakie.

7717

General Mach Discussion / Re: Newbie needs help

« on: March 10, 2009, 03:26:11 AM »

Hi Gerald,

We seem to have hijacked your thread over the license issue - sorry.

Have you now resolved the zero tool position on the work ?.

Tweakie.

7718

Show"N"Tell ( What you have made with your CNC machine.) / Re: Building a 4th Axis from scratch.

« on: March 09, 2009, 08:42:33 AM »

Thanks Guys.

I will post more pictures as the project progresses.

Tweakie.

7719

General Mach Discussion / Re: Can "Direction" &"Steps" signals be saved and stored in physical "memory"?

« on: March 09, 2009, 06:16:55 AM »

Whilst it may well be possible to route the LPT output to 'print to file' (as is done with plotters) the code produced (say a different alphabetical letter for each pin pulse) would be massive for even a simple GCode routine.

(I did try something similar to this a while back to convert 'Master CNC' step and direction outputs to GCode before I realized the size of the files produced).

Tweakie.

7720

General Mach Discussion / Re: General Q about kernel freq "noise"

« on: March 09, 2009, 06:02:36 AM »

From the sound of what you described it could well be lost (or gained) steps which are usually caused by noise spikes occurring in the LPT connection. You could check all your earthing connections are OK and make sure you do not have any ground loops (earthed both ends) also are you using screened cables ?.

Tweakie.