Lathes & M/C tools

[daifly]

Please could you share the issue numbers for these articles?

 

Thanks

 

Jon

 

You could start with issue 50 - an article by Paul Berntsen

Dave

[halfwit]

Some waffle and out-of-focus pics regarding turning boiler fitting on the Unimat on me blog for them wots interested.

 

The Unimat is a fine machine for 4mm work, I use mine on the dining table.

[laurenceb]

I believe Mike Sharman used to use his Lathe resting on his lap whilst in bed.....☺

As regards Unimats, I would agree that they are very useful lathes for the modeller; however there were inferior (east German etc) copies (see the Lathes website) and also there are plenty of abused and/or worn examples around, so be careful. Good examples do appear, but tend to command top dollar unless you are lucky. A Presto/Taig lathe is a good alternative

HTH

Brian

It was Malcolm Mitchell who used a lathe in bed, a Unimat

[Quarryscapes]

Does anyone know how to get the return spring out of the drilling stand of a Unimat 3? I would like to do a bit of tapping using the vertical column but need to get the spring out first. 

[RedgateModels]

Having finally fixed my Clarke CL250M (new speed controller board) I now fancy the milling attachment, so if anyone knows of a CL251MH going spare let me know

[Guest]

Hi All, I have used the original Unimat back in the 1980's and used it to build parts for a dozen or more locos and the fact that Guy Williams used one was good enough for me. The only issue I had with the lathe was when parting off or turning steel of around an inch diameter, those bed bars would vibrate and cause frightening chatter, parting off for me was something I didn't look forward to. As far as lathe designs are concerned, going way back to the 1900's, Webster Whitcomb designed and introduced a watchmakers lathe that was to become an industry standard, lots of manufactures copied the lathe and they became known as WW pattern lathes. The bed profile was 45mm diameter 'D' shaped with a centre height of 50mm, the beds on the earlier lathes were tool steel but later some manufacturers used cast iron. The really nice thing about the WW pattern lathe is that all parts were interchangeable between different manufactures and some companiies built their own lathes by combining  parts from different manufactures. So if your looking for a small kitchen table lathe, or even an in bed on your lap lathe, besides the traditional Unimat, Perris and Cowells there's also the WW pattern watchmaker lathes by Derbyshire, Leinen, Boley, Webster Whitcomb, Pultra and many more.

 

Here's more info on the watchmakers Lathe : http://www.lathes.co.uk/derbyshire/

 

What do I use ?, Unimat, Boley, Webster Whitcomb, Derbyshure, Pultra, Boley Leinen, Pratt Whitney.. and still looking from time to time...

 

Pete

[bertiedog]

The Unimat simply could not handle cut offs that big, but parting can nearly be eliminated in most model engineering, by sawing and refacing. It is just a different approach to the work. Parting is a factory production method to save time.

The Unimat can be easily uprated to stiffer bed rods, see the books by Rex Tingey etc.

Excellent lathe all round, but not as tough as some.

Stephen

[tender]

Thought i'd post a few pictures of my CNC conversion of my Proxxon MF70 Mini Mill

This is the MF70 with the added stepper motors to the x,y,z axis. 3 NMEA17 stepper motors - £30 from eBay

 

 

and this is the electronics, a Arduino Uno plus a GRBL compatible stepper driver. £15.99 from ebay.

 

 

So total conversion costs - £45 plus a bit of aluminium/nylon stock for the stepper mounts and couplings.

 

I've used Fusion360 to generate a CAD drawing and the CAM processor has a GRBL driver for generating the G-Code. This is sent to the CNC Mill using Universal G-Code Platform. All the software is free to download of the web.

If anybody wants more details, just ask and I'll do a more detailed post.

Just ordered up some more bits to convert my Sieg X2 mill, but that's going to take a bit longer.

[polybear]

If anybody wants more details, just ask and I'll do a more detailed post.

 

 

Yes please

[jdb82]

Thought i'd post a few pictures of my CNC conversion of my Proxxon MF70 Mini Mill

This is the MF70 with the added stepper motors to the x,y,z axis. 3 NMEA17 stepper motors - £30 from eBay

 

IMG_0435.jpg

 

and this is the electronics, a Arduino Uno plus a GRBL compatible stepper driver. £15.99 from ebay.

 

IMG_0436.jpg

 

So total conversion costs - £45 plus a bit of aluminium/nylon stock for the stepper mounts and couplings.

 

I've used Fusion360 to generate a CAD drawing and the CAM processor has a GRBL driver for generating the G-Code. This is sent to the CNC Mill using Universal G-Code Platform. All the software is free to download of the web.

If anybody wants more details, just ask and I'll do a more detailed post.

Just ordered up some more bits to convert my Sieg X2 mill, but that's going to take a bit longer.

 

Yes please!

[bertiedog]

Finally my Unimat needs an overhaul, replacing the bed rods etc to get rid of play, but also making new toolpost and making a thread chasing attachment, that is like the original had. but better tool holding. The lathe remains unmodified and can cut any TPI Imperial thread, metric threads or BA or any other pitch possible within the capacity of the machine.

 

The master thread fits the rear hole of the headstock, and diameter does not matter. the follow tip or thread form, made from a segment of a matching nut arranged to run on the sample thread.

 

This thread follower is coupled to a bar running along the whole bed at the back, and has a movable arm that has the cutting tool on it, resting for support on the tool support on the cross slide.

 

As the follower forces the tool to move, the tool tip is adjusted to cut the work. At the end of the thread the whole arm is lifted to disengage the follower and tool, which is then returned to the start and the process repeated till the thread is correct fit in a test nut, or measured. Threads can be external or internal or L/hand, it just copies the pitch of the follower. The quality of the threads made this way is unsurpassed.

 

The Unimat is perfect for this form of cutting threads, but similar ways could be adopted for other small lathes. 

The lathe already has extra low speeds as per Rex Tingey's book. but needs a powered fine feed developed for it, based on a shaft under the whole bed, with a stepper motor to power it timed from the main drive with an optical coupling.

It should require no major alterations to the basic design, just gears to couple the shaft to the manual bed feed screw.

I will do notes on these mods on a new posting Asap.

 

Stephen.

[tender]

Yes please

 

 

Yes please!

 

OK.

I'm a bit tied up this weekend but will post some more details early next week. Anything in particular you want to know? The Hardware side is pretty straightforward, i'll post some more close up pictures and describe all the software with links where to download. I'll also try and do a video of it in action.

[Vecchio]

Thought i'd post a few pictures of my CNC conversion of my Proxxon MF70 Mini Mill

This is the MF70 with the added stepper motors to the x,y,z axis. 3 NMEA17 stepper motors - £30 from eBay

 

IMG_0435.jpg

 

and this is the electronics, a Arduino Uno plus a GRBL compatible stepper driver. £15.99 from ebay.

 

IMG_0436.jpg

 

So total conversion costs - £45 plus a bit of aluminium/nylon stock for the stepper mounts and couplings.

 

I've used Fusion360 to generate a CAD drawing and the CAM processor has a GRBL driver for generating the G-Code. This is sent to the CNC Mill using Universal G-Code Platform. All the software is free to download of the web.

If anybody wants more details, just ask and I'll do a more detailed post.

Just ordered up some more bits to convert my Sieg X2 mill, but that's going to take a bit longer.

I am really interested also on your work on the Sieg X2 (for the simple reason that I have one in my workshop....)

best regards

Vecchio

[vindictive]

As abit of a comparison this is the lathe I use at work.

[KalKat]

'Crivens, Big Jobs!'

 

and 'wailey, wailey'

 

 

 

Emma

[Enterprisingwestern]

As abit of a comparison this is the lathe I use at work.

 

Aaah, but could you do crankpins, nuts and washers on it?

 

Mike.

Showing total ignorance of CNC lathe capabilities.

[Trog]

As abit of a comparison this is the lathe I use at work.

 

Takes 0.5 Seconds to turn a 00 buffer, but it then takes a week to find it in the bottom of the machine.

[vindictive]

Yeah it will do most things, my boss is letting me make some new hornblocks for my jltrt pannier kit tomorrow. It's a lathe with full milling capabilities too. I will attach a picture of some new wheel studs and nuts I made for my ww2 Bedford lorry. It will still do tiny parts but as was already mentioned finding them can be a challenge!

Also the nuts where done complete, including the hexagon in one operation. 12 minutes a piece, and 3 and a half minutes a piece for the studs.

[tender]

PROXXON MF70 MILL CNC CONVERSION

 

Hi again, for those who wanted some more info on my MF70 mill CNC conversion, here is Part 1 which shows all the hardware side. I'll say it mostly in pictures. Nothing needs modifying on the MF70, its fully reversible in a few minutes.

The Stepper motors are NEMA17 1.9deg steppers, about £10 each ebay.

This is the X-Y table before conversion.

 

 

The X-Y motor mounts are identical. Firstly the handle is removed leaving the aluminium disc and scale

The Motor mounts are attached using the two screw holes that attach the end plates to the table extrusion. 

The Screws are self tappers into the aluminium extrusion. Longer screws are required to make up the thickness of the mounting plate.

The nylon coupling fits snugly over the aluminium disc and held with a fixing screw into the tapped hole left by the handle.

and a grub screw onto the motor shaft.

The motor is fitted with two screws to the rear mounting plate.

The Z axis is similar except for the position of the fixing screws. Two hex bolts that hold the top plate on are removed and replaced with longer screws to accommodate the motor mount.

The electronics consist of an Arduino Uno and a GRBL(version3) Shield with 3 Stepper Drivers. All from eBay for about £16

The bits just plug together, no soldering of small components required.

You will have to solder some 4 pin header strips to the motor leads. Here shown in a box (Arduino) and mounted on the rear column with a 12v 5Amp PSU. (Edit the steppers in the link above come pre-wired with the header plug fitted.)

The completed conversion.

 

In Part II i'll describe setting up the steppers and loading the GRBL software into the Arduino.

 

 

Edit: Somewhere i have some back of envelope sketches of the bits for the mounts but they might take some finding. It should be pretty clear from the pictures what is required.

 

Edit: Edit: If you don't want to make your own mounts, Google 'Proxxon MF70 CNC kit' you should get a few hits for the stepper mountings. I'd avoid anything 3D printed as the motors do get a bit warm. This looks ok @ $45.65 if you've got money to burn.

Edited March 20, 2018 by tender

[tender]

PROXXON MF70 MILL CNC CONVERSION

 

So Part II will be mostly about the software but before going there you need to set a current limit for the steppers.

You need a DC meter (preferably digital) set to about 2vdc full scale and a very small pozi-head screwdriver.

Connect the negative lead of the meter to 0v (- on the 12-36v socket on the shield) and the positive lead to the screwdriver.

 

Plug the three stepper drivers into the 3 axis sockets X,Y,Z of the shield and plug the shield onto the Arduino Uno. Leave the motors unconnected at this stage.

Apply 12v DC to the 12v-36v terminals on the shield, make sure you get them the correct way round.

 

Working with each stepper driver in turn. Adjust the tiny pot on the board with the screwdriver so the meter reads about 250mV.

Theres a YouTube video here showing this but it gets a bit technical. If you set it to 250mV you won't be far off, if later you find the stepper missing steps you can increase the voltage up to about 400mV.

(Fast forward to about 3:30 in the video to see setting the voltage)

 

Back later with the software install.

 

 

 

[tender]

PROXXON MF70 MILL CNC CONVERSION

 

​So, for the software I am going to assume some knowledge of downloading and installing software on a PC/Laptop.

​If you're really stuck just ask for help.

 

You need to download and install three packages.

 

The first is the Arduino IDE to talk to and upload the GRBL software to the Arduino.

 

Get it here and follow the instructions to connect to the Arduino Uno.

 

Next download the GRBL installer from here https://github.com/Protoneer/GRBL-Arduino-Library/archive/master.zip unzip the folder and move to 'Documents/Arduino/Libraries'

 

Start the Arduino IDE and connect to the UNO.

 

Under 'File' -  'Examples' scroll down until you see GRBL and select GRBLtoARDUINO

(if you don't see it goto 'Skecth' - 'Import Library' - 'Add Library' and Select GRBL from 'Documents/Arduino/Libraries')

 

Click on the 'Upload' (right arrow) button. The GRBL code should compile and upload to the Arduino Uno.

 

Next Download and install USG Platform  (Universal G-Code Platform) from here http://winder.github.io/ugs_website/download/

Start the UGS (ugsplatform64.exe)

Select the COM port the Arduino is connected to and click on the 'Connect' icon.

You should get the status of the GRBL in the console window of the UGS followed by 'ok'.

 

If you get this far now is the time to plug-in the steppers (power off first) and try moving them with the 'Jog Controller' of the UGS.

but first you need to set the steps/mm for the three steppers.

The Proxxon MF70 has 1mm/turn on all axes and the steppers have 200 step/revolution, we need to set the step/mm to 200.

 

At the bottom of the console window in the 'commands' line type

$0=200.0

$1=200.0

$3=200.0

We also want to limit the speed of the feeds so to start set them all to 50

$4=50.0

$5=50.0

 

Now try the Jog Controller. 

Set the 'XY Step' and Z step to 1

clicking on the X,Y and Z buttons should now move the steppers 1 revolution and if connected to the MF70 move the table/height by 1mm.

 

You now need to generate some G-Code and load it from a file in UGS.

I use Fusion360 (free to download from https://www.autodesk.co.uk/products/fusion-360/free-trial)as it has a GRBL driver in the CAM to generate the G-code in the correct format for the GRBL interface.

Download the free trail and register for non-commercial use to extend usage.

Lots of tutorials on YouTube. Or you can use your favorite CAD/CAM.

 

Good luck, and if you get stuck just ask.

 

Edit:

I'll try and upload some screen shots later with a video of the system in operation.

Edited March 21, 2018 by tender

[tender]

PROXXON MF70 MILL CNC CONVERSION (screenshots)

 

Arduino IDE

 

 

UGS (Universal G-Code Sender Platform)

 

 

Video, testing operation

 

Edited March 21, 2018 by tender

[polybear]

Many thanks for taking so much time and trouble to post all this for us

 

Just one point - the link in post 902 appears out of date now:

 

https://www.autodesk.co.uk/products/fusion-360/free-trial)

 

Cheers,

Brian

[tender]

I am really interested also on your work on the Sieg X2 (for the simple reason that I have one in my workshop....)

best regards

Vecchio

 

Well, i've been busy again in the workshop. This time a partial CNC conversion to my Sieg X2Plus.

Only done the X,Y axis so far as the Z axis is going to be a bit more complex as the current drive is via a rack and pinion on the column.

Heres an overview: (excuse the mess) and its very much a lash-up at present.

The X axes drive:

The Y axes Drive:

Both drives are essentialy the same being made from 2 pieces of 12mm nylon sheet. One bored out to 22mm to take a 22x8mm ball race (skateboard), the other drilled 8.5 mm clearance for the screw shaft. This also has the 4 nylon pillars for the motor (NMEA23) mounting attached. Each side of the nylon sheets are a 16x8mm thrust roller bearing to remove any backlash in the motor mounting. The motor is connected to the existing screw shaft using a 'lovejoy' coupling, one side reamed out to 1/4" for the motor shaft the other drilled and reamed to 8mm plus 3mm keyway for the screw shaft. It is also counterbored on the inside to take the M6 shaft nut.

Two M6 bolts mount the unit onto the bed using the existing tapped mounting holes for the old hand wheel drive.

 

The drive electronics for the Proxxon MF70 mill conversion (see above) were not going to be man enough for the steppers on this conversion so a pair of 4amp drivers and 24volt 5amp PSU were obtained from ebay.

 

This time I'm using MACH3 software so a USB motion controller and breakout board were used to connect the stepper drivers to the PC. (no limit switches connected as yet)

 

Here's a bit of youtube testing for lost steps and the effectiveness of Mach 3's backlash compensation, cycling between x0,y0 and x4.0,y4.0 (backlash in the siege X2 screws were about 0.175mm). As can be seen on the independent DRO mounted on the mill the x and y readings oscillating between 0.000 and 4.000 indicate all's well so far.

 

 

Hope this is of interest.

Ray.

Edited July 13, 2018 by tender

[richbrummitt]

Thank you. After reading your post on the MF70 and watching a few videos I decided to get on with it. So far I have the motors attached to the shield and stepping away happily when jogged. I did find anything over 350mV and I had missed steps with just one of the motors. Next thing is to try and generate then send some g code before attaching to the mill. Estlecam is probably something I'm going to try after that because it looks perfectly adapted to what I want from the machine - profile milling.

 

What would be really nice is to be able to run without the computer attached. More research required...