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

**m_c** · 04-09-2016

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** · 04-09-2016

Originally Posted by m_c

Where about is middle of nowhere?

Anywhere north of Watford Gap.

**Rob** · 05-09-2016

Originally Posted by 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 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** · 05-09-2016

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.

**m_c** · 05-09-2016

I'm based near Edinburgh, but am occasionally in various corners of the country, and if I happened to be near wherever you are, I'd be happy to pop in for an hour or so.

There is one main standard for lathe tool holders, however there are also some manufacturer specific types, but they tend to use non-standard codes.
The key bit of info are the letters, as they tell you the insert type, toolholder style, and orientation. The numbers that follow are the shank size. Then the final code is the insert tolerance/size.

A SDNCN 1212 M11 takes a DCMT 11T3 insert
The SDJCL/R are left and right versions of the same tool, however the left hand version takes a DCMT 11T3 insert, whereas the right hand takes a smaller DCMT 0902, however 0902 is not a common size, so you'd be better to buy a new holder.
www.shop-apt.co.uk is a reasonable source for tools and inserts.

What I meant by tools lining up, is provided the tool disc/holder and the ratchet has been machined correctly, once you have one tool at the correct height, they should all be at the correct height when in the cutting position. If you're having to adjust the height of individual tools, then something is not right.
When I bolt a tool into my turret, I don't have to adjust it's height. If the height is wrong, then I have an alignment issue and all the tool heights are wrong.

If homing is working with suitable switches, when you click the Home (I think, it's been that long since I've used Mach 3, it might actually be Set Home) button for the axis, the corresponding axis should then carry out a homing routine.

**Rob** · 05-09-2016

Originally Posted by m_c

I'm based near Edinburgh, but am occasionally in various corners of the country, and if I happened to be near wherever you are, I'd be happy to pop in for an hour or so.

There is one main standard for lathe tool holders, however there are also some manufacturer specific types, but they tend to use non-standard codes.
The key bit of info are the letters, as they tell you the insert type, toolholder style, and orientation. The numbers that follow are the shank size. Then the final code is the insert tolerance/size.

A SDNCN 1212 M11 takes a DCMT 11T3 insert
The SDJCL/R are left and right versions of the same tool, however the left hand version takes a DCMT 11T3 insert, whereas the right hand takes a smaller DCMT 0902, however 0902 is not a common size, so you'd be better to buy a new holder.
www.shop-apt.co.uk is a reasonable source for tools and inserts.

What I meant by tools lining up, is provided the tool disc/holder and the ratchet has been machined correctly, once you have one tool at the correct height, they should all be at the correct height when in the cutting position. If you're having to adjust the height of individual tools, then something is not right.
When I bolt a tool into my turret, I don't have to adjust it's height. If the height is wrong, then I have an alignment issue and all the tool heights are wrong.

If homing is working with suitable switches, when you click the Home (I think, it's been that long since I've used Mach 3, it might actually be Set Home) button for the axis, the corresponding axis should then carry out a homing routine.

Thank you so much for this info, lots to learn. I will check out the link for tools.

For the tool turret alignment and the homing issue, to make this easier I will make a short video tonight showing what is happening and post it tomorrow.

One other thing, do you or anyone reading this know what equivalent grease to use for the Orac headstock and zerk nipples? I bought some "slide oil" for the bed and screws from ebay so that's covered. I know the grease is some sort of lithium hydroxystearate grease, but anyone have advice on this as I see various ratings like "EP2" and other ratings on ebay. What is good for a headstock?

Here is part of the manual's lubrication instructions:

Add grease sparingly to the Headstock bearings through Grease Nipples at back of
Headstock. GREASE: ALVANIA No3 or SPHEEROL AP 3

I live in Crianlarich, Stirling. People only travel through here at as fast as possible, there is even a new by-pass, lol. If you're ever travelling to Oban or Fort William way some time in the future it would be a pleasure to meet you and get some advice. Please let me know a couple of days in advance so I'm not off somewhere.

**Rob** · 16-09-2016

I think I found a limit switch, not sure, hopefully I can get some pics on here soon. One thing I noticed is when in manual there are various options for homing but in auto there are only two, no idea why.

Another thing I tried is to get a simple wizard to do something (a groove) but no result. It's so confusing and I can't find documentation for all the little things it tells me is happening. If I could just get a wizard to make one move it would be fantastic.