My comical CNC lathe story and does anyone have experience with gang toolposts?

[m_c]

drop mach3, use linuxcnc.

probably your auto changer will work fine (mine does). Post pictures and i can comment more...

So changing controller software will fix a mechanical problem?

[magicniner]

So changing controller software will fix a mechanical problem?

Ah, but for some Linux is more of a Religion than a tool for a job, it's mystical properties, not revealed to non-initiates, can solve not just mechanical problems but also cure coughs, colds and pimples on the makewater!

:D

[i2i]

changing to linux will not sort your problem, all that will do is to give a massive headache.

Right getting on to the real problem, the simplest way to cure this is to lengthen the "pawl", this is the rectangular part that catches on the rachet wheel. Similar tool changers to this have an adjustable end stop for the pawl which sets the tool position relative to the centre line of the lathe.

Or you could raise the whole tool changer to match the centre line, but this may give your tools a bit of positive rake.

I'll pm you my mobile number if you need a chat.

Tom.

[Rob]

changing to linux will not sort your problem, all that will do is to give a massive headache.

Right getting on to the real problem, the simplest way to cure this is to lengthen the "pawl", this is the rectangular part that catches on the rachet wheel. Similar tool changers to this have an adjustable end stop for the pawl which sets the tool position relative to the centre line of the lathe.

Or you could raise the whole tool changer to match the centre line, but this may give your tools a bit of positive rake.

I'll pm you my mobile number if you need a chat.

Tom.

Hi Tom, thanks for the reply, haven't checked in for a couple of days...

The linux/mach3 debate, maybe one day I'll have a proper cnc machine such as a Hass that comes with dedicated software but until then I'll stick with Mach3 because at least I have learnt to use the jog buttons, lol, yes I have a long way to go. The home/referencing thing is doing my head in right now. Then there is the offsets, then actually getting a wizard to do something, then fingering out how to string them together. And that's just the software! How to find where to buy cutting inserts that go with the tools I have, %&%$&% if I can find them even after calling the UK office of the manufacture and them sending me on a wild goose chase. Ok, too much pouring out my frustrations with this lathe/cnc steep learning curve, it's all fun, on to the auto-changer...

This thing is a bad design in my opinion, I am not a pro but if I was to design it, each individual tool would have an adjustment of a few mil either way up and down without having to use a shim of some sort. The paw that clicks into the ratchet wheel on this thing has two Allen bolts which are loosened to adjust the wheel and tool face relative to the work piece but only for one tool so the rest need shims if not aligned up naturally. The problem is not really aligning the tool, it's keeping the alignment where it is once tightening the bolts. This is why I will align one of the tools then drill the two parts and put a dowel pin in, at least then they will not move out of alignment, I hope.

I think this auto-changer problem has been figured out, it's the Mach3 software that is the headache and really need help with. The manual is good but there are some confusing things about the referencing/homing I don't understand (yet). Step by step. If I can get past this basic cnc stuff then hopefully I can get using this lathe properly. It is a nice lathe overall and hopefully it will do what was intended until I deserve a better one.

Cheers
Rob

[m_c]

If the turret has been machined correctly, then all the tool slots should be at identical heights, so you shouldn't need any shims as long as you are using the correct size of toolholder.
Regarding inserts, post up any numbers on what you have, as there are only a few different basic shapes of inserts for lathes, unless the holder is for something very specific.

Referencing a lathe in Mach, depends on if it has homing switches or not. If it doesn't have homing switches, then personally I'd add at least one on the X-axis, as that is the most critical axis.
However, in a nutshell, without homing switches, all tool offsets are taken as on offset from your master tool. At startup, you take a test cut with the master tool, measure the cut, and enter the size into the DRO, so Mach then has a known reference point.
If you have homing, then you don't have a master tool, and all tool offsets are an offset from the home/reference position.

Where about is middle of nowhere?

[John S]

Where about is middle of nowhere?

Anywhere north of Watford Gap.

[Rob]

If the turret has been machined correctly, then all the tool slots should be at identical heights, so you shouldn't need any shims as long as you are using the correct size of toolholder.
Regarding inserts, post up any numbers on what you have, as there are only a few different basic shapes of inserts for lathes, unless the holder is for something very specific.

Referencing a lathe in Mach, depends on if it has homing switches or not. If it doesn't have homing switches, then personally I'd add at least one on the X-axis, as that is the most critical axis.
However, in a nutshell, without homing switches, all tool offsets are taken as on offset from your master tool. At startup, you take a test cut with the master tool, measure the cut, and enter the size into the DRO, so Mach then has a known reference point.
If you have homing, then you don't have a master tool, and all tool offsets are an offset from the home/reference position.

Where about is middle of nowhere?

John is right, middle of no-where in my case is far north of the WG, a rural village in Scotland. Went to look for gold and got stuck here.

I was wondering if there was a tool insert standard. I have some Tizit tool holders:

sdncn 1212 m11, Ceratizit stock number 221870
sdjcl 1212 H11, Ceratizit stock number 7068521200
sdjcr 1212 f09 , Ceratizit stock number 77343

For the parting tool I bought a new one which I can get inserts off ebay for instead of trying to finding the Ceratizit ones.

I don't understand what you mean by correct size of tool holder. The holder is the turret slots in the wheel, there are no individual adjustment. The adjustment on the cog wheel adjusts them all at the same time, it would be impossible to line them all up this way.

What you say about the referencing/homing is pretty much what the mach3 manual says also, but I don't know how to determine if there is a homing switch or not. The original manual for the Orac says there are homing switches, so maybe there is. I can understand generally what your saying and the manual, but I'm finding it confusing on some points like I don't know how to test if the homing works because it seems to need a cutting program to run, or maybe not, this is the confusing part. Once I understand how to make this work then it's just getting the wizards to work. Getting closer.

There is one program I really like, it's Denford's 2D quick turn cad/cam for turning as it's really easy to use being made for teaching in schools, but it's £168 and it's not possible to try the code first to see if it works with Mach3, although it does say it can save a .tap file. Anyway, I'll use the wizards first to learn and then hopefully move on to some cad/cam software.

[Clive S]

The original manual for the Orac says there are homing switches, so maybe there is.

Rob Some good clear pictures of your lathes might be helpful in determining what and where the switches are if any.