Sherline 2000 CNC Mill

[Jonathan]

Make sure the DTI is precisely parallel to the slide, otherwise you may get a false reading. Off by about 11° is enough to account for a 0.1mm discrepancy in 5mm.

[cooliced]

i had it viced using the bolt hole on the back and squared the vice so it should have been good.

So i put the settings in that you suggested and it is spot on tbh. i cut a 15 hole and it was actually round! im very happy and thank you for your help

[black5f]

According to the Sherline website:
http://www.sherline.com/setupins.htm
The manual imperial mill gives 0.050" as the distance of one turn. So this makes it 20 tpi, ie a pitch of 1.27mm. I also say sthat the Sherline steppers are 0.9 degrees step
http://www.sherline.com/CNCfaq.htm
ie, 400 steps per revolution = 1.27 mm which means for you, 314.9606 steps per mm.
Yours are set to 320 per mm which will give 1.2903 mm per revolution.
So if you programmed a 5 mm move (Mach 3 will think this is 1600 steps), and it moved 1600 steps, you would actually move 1600/314.9606 = 5.08 mm which is what I origionally suggested.
I am not famiiar with Mach 3. Is there a way of entering steps per mm fraction? Waht you really want is 320 per 1.27mm. If you used 315 steps per mm you would be 0.125mm out over a meter. According to the specs, the longest travel is the X axis with is 9 inches = 228mm, 315 steps per mm would make full travel 0.029 mm too long. Not very much! The answer for exact acuracy if there is such a thing is to routinely scale all cad files by 0.9987 and use 315 steps per mm or order and fit metric screws.
Does that help? Anyway, I'd love one. I have an old (but very good nick) Isel mill, extruded, about A4 cutting area, preloaded ball screws, recirculating bearings and servo driven, home brew software. But I've lost some garage space and something may have to give at some point, all very sad.

Tom

[cooliced]

Tom, thank you very much mate, im not the best at these sort of calculations and you got it spot on. ive been cutting things for the last 5 days and its been ace!

Thank you again.

Next part of the build for this little monster is a coolant booth!

Btw, ive been cutting aluminium at 400 Feed and a D.O.C of 0.3 at 2800 RPM, seems to be solid so far, might try 0.5mm D.O.C tonight:whistling:

[black5f]

No problem mate and brilliant! I've always been tempted to get a Sherline spindle and motor for my CNC. They are really well made and have a lot of power and run quietly. I currently use Kress, no load speed good but if you need any power, speed drops dramatically which makes it really hard to get the speed right. And I find they get very hot. With a Sherline spindle you've got very good speed control and it would be quite happy with a 1/8" end mill or a 2 inch fly cutter. My lathes 12 years old now, never adjusted, origional belt and still perfect. Made 8, 48mm diameter cast iron wheels with it once, it never complained a bit. Never tried to swap the one on the lathe in case of accidents though. They are very nice machines! It should be happy with mild steel but yes, coolant will help a lot, with ali or brass you can use just water or if you don't push it too hard, compressed air. Anyway, it's all about having fun!

This is my rather over engineered beasty:

Some tests during a "rebuild"

http://www.youtube.com/watch?v=8MmqX...eature=related

Some quick moves to test for following errors after the "rebuild". It has one serious limitation, the data packets are RS232 so that limits complex moves to about 10 a second, circles or arcs are just one command so can be quick. MACH3s innovative use of a parallel port leaves it in the dust (which there is an awful lot of!).

http://www.youtube.com/watch?v=KGCIQ...eature=related

Tom

[cooliced]

forgot to mention i was using a 6mm roughing endmill

i would love a fly cutter, just cant find anybody that sells the sherline ones

[black5f]

I used to get my bits from here:
Millhill Supplies Ltd.
Unit 37, Broton Drive, Halstead, Essex C09 1HB, UK
Tel: ++44 (0) 1787 472236, Fax: ++44 (0) 1787 477797
E-mail: [email protected]
Website: www.millhillsupplies.co.uk

That was a few years ago, their website seems live! Chronos do a small cheap set, OK for light cuts!

[cooliced]

Thanks for the link mate. gonna be ordering some bits from them soon.

So after posting in the single flute thread, i thought i would push my machine with a number of different endmills

with a 3 flute carbide 6mm endmill, i was pushing 1.5mm DOC at 350mm/min <- this i was very happy with

With a 2 flute HSS 6mm endmill (cheap, from ebay for 3 quid), i managed to get 3mm DOC at 225mm/min <- even more happier with this..

I cant wait to get the single flute carbide ones. hopefully go 3-4mm deep at 300mm/min would be the best thing ever..

Also im gonna start a dedicated youtube channel for my projects

Thanks for looking

Stu

[black5f]

Hi Mate

No problem, just make sure you pm me to point me at your youtube, interested to see how you get on! I'm black5f on YT as well, basically , a black 5 is a steam engine!

Make sure your endmills are capable of plunge cutting if thats what you need to do. Endmills will give a flat face, they have a flat end, but cannot always cut nicely in plunge and on hard materials and can skate a bit before they bite. One of the teeth needs to extend all the way across the centre, so they are not symetrical when looked at from the bottom. Slot drils will plunge and slot but don't give such a clean bottom to the slot. Most end mils plunge nicely but beacause they are flat, I find you get a neater finnish on blind slots if the plunge is taken a bit gentler. At the end of the day you just have to play with speeds and feeds till your happy with the finnish. Try some nickle silver, it's nice to cut, chips nicely and doesn't tarnish. Sounds like your having fun!

Tom

[Jonathan]

I'm black5f on YT as well, basically , a black 5 is a steam engine!

Or at the model railway club I'm a member of it was tea with no milk and 5 sugars!

Make sure your endmills are capable of plunge cutting if thats what you need to do.

Single flute cutters are good at plunging, but I still use ramping (spiral toolpaths) on the router. As long as the ramp angle isn't really steep it's much better.