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Posted: Sat Nov 12, 2011 4:38 pm
by Gun Freak
Hm... I could use my wood lathe to make a plastic lathe... use my plastic lathe to make an aluminum lathe... use my aluminum lathe to make a steel lathe :lol:

Posted: Sat Nov 12, 2011 4:44 pm
by POLAND_SPUD

Posted: Sat Nov 12, 2011 11:10 pm
by evilvet
Hi JSR

You might remember my first CNC build
http://www.spudfiles.com/forums/electro ... rt,15.html

In the interests of machining parts for my dream pneumatic I am going to spend this summer on a new CNC build, the fun part of which is the old machine will fabricate many of the parts for the new. So far I have spent $850 on the motors and controllers and $400 on two lead screws. I expect it will run out to about $3000 when i am finished but that will give me a CNC mill that has a work area of 1200mm x 600mm and enough grunt to machine anything up to mild steel.

If you are serious about doing the Sherline conversion yourself, hop over to http://www.cnczone.com/forums/mini_lathe/ and have a poke about, you will find every version and opinion on converting a Sherline you could want.

Cheers

Posted: Sun Nov 13, 2011 3:49 am
by jackssmirkingrevenge
This is not very encouraging:
http://www.cnczone.com/forums/benchtop_machines/6175-sherline_mill_cnc_conversion.html wrote:CNC will put a lot more wear and tear on the mill.

It really isn't appropriate to use for production. I suggest you keep your current Sherline for prototype work, then buy something a bit beefier for production.

I tried using a Sherline CNC mill for production, and here were my problems:

- backlash increased to unacceptable levels very quickly

- repeatability is not good enough, especially when you are using the extents of the travel to make a lot of parts. For instance, I used a spot drilling cycle, then two drilling cycles, and then two milling cycles for a single lot of twelve parts. The lead screws' relatively low quality/accuracy/repeatability was not good enough to use the entire table, and the finished parts were unacceptable. I can only effectively use 1/4 to 1/3 of the table for production type work.

- You will find yourself increasing spindle speed so you can increase feeds. The leadscrew pitch is very low, and steppers will run out of speed very quickly. My metric Sherline mill is maxed out at ~18 inches/minute, and I dare not go faster in fear of lost steps. I am using 3/16" 4 flute endmills in tempered aluminum, and it needs to feed faster (with 5500 rpm pulleys).
Booooooo...
I am going to spend this summer on a new CNC build, the fun part of which is the old machine will fabricate many of the parts for the new. So far I have spent $850 on the motors and controllers and $400 on two lead screws. I expect it will run out to about $3000 when i am finished but that will give me a CNC mill that has a work area of 1200mm x 600mm and enough grunt to machine anything up to mild steel.


That sounds like a beast!

You know, when you think of it in terms of basic function, it doesn't sound like a daunting task to make your own, especially already having the benefit of a manual lathe and mill.

Any online plans for something smaller you'd recommend?

Posted: Sun Nov 13, 2011 4:32 am
by jackssmirkingrevenge
POLAND_SPUD wrote:check ebay.com
Wow... this is actually very reasonably priced: http://www.ebay.com/itm/CNC-Kit-3-Axis- ... 45fa68c680

Plus power supply and a fourth stepper motor still makes it reasonably priced: http://www.ebay.com/itm/4-AXIS-CNC-Rout ... 3cbc4fc9a1
Always better to get it from the horses mouth rather than the other end.


:D
Yep, been looking through it.
Cheers for that!
I saw someone on youtube, who made cheapish mounts by hand with an easy to machine plastic. Then used the cnc to make nice time consuming aluminum ones
Thinking about it they shouldn't be such a chore.

Hmmm...

This is off-putting though.

Maybe the comments are from someone who's been working beyond the real limitations of the Sherline?

Posted: Sun Nov 13, 2011 5:50 am
by al-xg
Yeah, not sure you can call your use "production".

Going CNC on a Sherline should be more about getting geometry you could not achieve beforehand, in my opinion.


Haha, you can connect a PlayStation style controller to that one on the Ebay link! :lol:
It does really seem a bit too cheap, but comparatively, it seems worth a try, you could swap all the parts over for better ones and it would still be cheaper than the first two links posted.

Posted: Sun Nov 13, 2011 6:53 am
by jackssmirkingrevenge
al-xg wrote:Yeah, not sure you can call your use "production".

Going CNC on a Sherline should be more about getting geometry you could not achieve beforehand, in my opinion.
Not sure I'm happy losing the manual option either... or will I?
The Sherline conversions do include the handwheels that would normally come with any given machine. When using a dual-shaft stepper motor, this means you can still turn the handwheels for manual control if you so desire. (NOTE: the stepper motor should be disconnected before you do so to keep it from acting as a generator and possibly damaging your computer.)

Haha, you can connect a PlayStation style controller to that one on the Ebay link! :lol:
POLAND_SPUD suggesting it could be used as a driver for a sentry gun in 3...2...

:D
It does really seem a bit too cheap, but comparatively, it seems worth a try, you could swap all the parts over for better ones and it would still be cheaper than the first two links posted
I'll bet that it works just as well as more expensive options.

Posted: Sun Nov 13, 2011 7:22 am
by al-xg
I'll bet that it works just as well as more expensive options.
Indeed and finding out isn't that expensive :)
or will I?
Just need to make sure, either you can affix a hand wheel to the back of the stepper or have a method of quick removal of the motor.

Posted: Sun Nov 13, 2011 8:13 am
by mark.f
jackssmirkingrevenge wrote:I will dare make a prediction, by this time next year I will have CNC up and running.
*hammers rivets into leg irons*

Git to werk son. *spit*

Posted: Sun Nov 13, 2011 10:58 am
by POLAND_SPUD
POLAND_SPUD suggesting it could be used as a driver for a sentry gun in 3...2...
That DID cross my mind :D

Posted: Sun Nov 13, 2011 11:34 am
by velocity3x
JSR,
The links you provided for CNC conversion kits are great prices. However, the single most important and most overlooked factor in a conversion is swapping the acme screws for ball screws. A CNC machine with acme screws is worthless. I'm sure that ball screws will cost more than the conversion kits in your links. I converted my 9x49 knee mill about 11 years ago. The x / y ball screws cost $1,300.00

Because Sherline is so popular, I'm sure these people would have them on the shelf.
http://www.rockfordballscrew.com/

Posted: Sun Nov 13, 2011 1:37 pm
by jackssmirkingrevenge
velocity3x wrote:Because Sherline is so popular, I'm sure these people would have them on the shelf
Actually, it seems that size constraints do not allow this on the Sherline, at least not without extensive modification.

This one is interesting:
I also replaced the brass leadscrew nuts with cast in place Moglice. Moglice is an epoxy product made for macine repair. The nuts are working perfectly- I have ZERO backlash and lower drag than the brass nuts. I think this is a nice solution for a Sherline where fitting ball screws would be very hard.

Posted: Sun Nov 13, 2011 4:11 pm
by POLAND_SPUD
yeah get a CNC kit.... bi##### love cnc mills

PUI!!

Posted: Sun Nov 13, 2011 6:31 pm
by Fnord
This thread is one of the reasons I'd like to see SF still online 10-20 years from now. I can just see us uploading cad files with our finished launcher posts...
Like my gun, guys? Print out a copy and give it a whirl!

Posted: Sun Nov 13, 2011 6:36 pm
by jor2daje
just grab this whole mill for less than the price of a conversion

http://www.ebay.com/itm/160677962501?ss ... 1423.l2649