# CNC Sherline Lathe Project



## vlmarshall (Feb 17, 2010)

Well, I've finally managed to get a lathe at home!

To compliment my little Sherline mill, I've paired it with a Sherline lathe, which I'll be converting to a CNC machine.

For now, it's a basic "CNC Ready" lathe (thrust bearings on the leadscrews, and motor mounts already fitted from the factory), a pair of stepper motors, and a pile of goodies.


----------



## vlmarshall (Feb 17, 2010)

One of the first troubles was this crunched power supply. The box arrived via our fine postal service, in a rather sad state. Accordion'ed for most of it's length, no single panel of the box was undamaged, and a rather large hole had been covered by some randomly-applied packing tape. Most of the contents were ok, except for the 48v power supply.

Luckily, there was a lot of crush-space between the chassis and circuit board... I never thought I'd repair a power supply with a hammer...





The supplier, KelingCNC, was ok with my disassembling it and 'repairs', and say they'll replace it if it doesn't work.

I've already smoke-tested it... it works just fine.


----------



## vlmarshall (Feb 17, 2010)

Next up, the cute little toolpost from A2ZCNC. All aluminum and Sherline sized, this QCTP falls somewhere between building my own, and buying that Aloris I've always wanted.


Not happy with the chattery finish on the locking cam and center post, I couldn't resist cleaning up the finish on both.

Before:





After:





The locking lever is next. I should have cleaned up that off-center center hole while I was at it. 

The BOTTOM of this toolpost was not machined, but left as-sawn! It also wasn't square to the dovetails, cleaning it up took almost .020"





While I was facing the 'post body, I skimmed the two non-dovetail sides, as they were both unmachined raw stock finish, and I'll be re-anodizing the body anyway, since almost every edge on the toolpost was not deburred after machining.

Skimming .020" off the bottom of the toolpost caused the tool holders to run out of adjustment when using 1/4" tools, so I skimmed a bit off of the holders, as well.






The slot for the parting tool is not cut straight, and because it's been machined in YET ANOTHER raw-stock surface, the slightly undersize material causes the slot to fade away to almost nothing at one end. Either that or the burr they left on the dovetail side caused the part to sit incorrectly for machining.





Yet another part for the anodizing bath...


----------



## Tin Falcon (Feb 17, 2010)

vernon: nice lathe and a heap of goodies. I am planning on converting my little old Machinex to cnc. I do not plan on doing a full build just connector to motos I jut bought . Use the same PS, g540, computer etc that is hooked to the mill. i will have to figure out some sort of quick disconnect for limit switches and a motor connector if and when I hook up spindle control to the 540.
Tin


----------



## zeeprogrammer (Feb 17, 2010)

I didn't see this when I replied in your other thread...not that I'm sorry for what I said ;D.

Excellent Vernon. You're back in business. Sorry for the troubles.
Shipping issues on the PS is one thing...quality of parts (A2Z) is another.
Good to know.

I've often wondered if I should have gone with that kind of system. There's a lot to be said about the breadth of product Sherline offers...as well as the quality. At the time I wasn't even sure if this hobby was for me....and that affected my decisions. (Having said that...I'm very happy with my decisions...for one thing...I'm enjoying the heck out of this hobby and this forum.)

Hm...wait...I remember you...this calls for a shout.


----------



## ksouers (Feb 17, 2010)

Vernon,
Congrats on the new Sherline. You already know they are great little machines.

Really sorry to hear about the sad state of the A2Z tool post. I bought one a few years ago for my C2 and it's very well finished.


----------



## steamboatmodel (Feb 18, 2010)

Hi Vernon,
Does the Shirline have Ball Screws or regular lead screws?
Regards,
Gerald.


----------



## vlmarshall (Feb 18, 2010)

steamboatmodel  said:
			
		

> Hi Vernon,
> Does the Shirline have Ball Screws or regular lead screws?
> Regards,
> Gerald.



Regular thread lead screws. Tiny, too, 1/4"-20. I've seen small Acme thread, but never a ball screw small enough to retrofit... but I'm looking.


----------



## Speedy (Feb 23, 2010)

ooo very nice!

is it in action?


----------



## vlmarshall (Feb 23, 2010)

Speedy  said:
			
		

> ooo very nice!
> 
> is it in action?




Thanks!
It's wired and cutting air, but all of my electronics are scattered all over the desk at the moment, so I'm not about to throw metal chips! 

I also need to make a slotted wheel for the spindle index, and get it onto a real stand...but I plan to be cutting parts for my Crackers by this weekend.


----------



## Speedy (Feb 24, 2010)

sounds goooooood! 
lots of videos and pictures..... okay 8) :big: serious tho ;D


----------



## vlmarshall (Mar 5, 2010)

Here's another lathe update.

To rework that parting tool holder, I couldn't just throw it in a vise, and hack at the tool's seating surface, because none of the outer surfaces of the holder are squared up.
So, I set up the toolpost in my mill, and locked the holder into it's working position.






The first pass should give you an idea of how far out this thing was.
After a few passes, I'd gone in far enough to make the 'shelf' at the bottom the full width of the parting blade, so I cut the step at the top and called it "done".





Hopefully tomorrow, all of this stuff will be re-anodized.


----------



## vlmarshall (Mar 5, 2010)

All of the electronics are tucked away in a plastic tub, at least for now.










It moves!





Guess I should write some code and actually CUT something... but at least I know the parting tool holder works.
Just for grins I hacked at a piece of brass hex stock with it.





I still need to set up the spindle encoder and speed control...but at least it's making chips.


----------



## zeeprogrammer (Mar 5, 2010)

Nice.
Did you make that table the lathe is sitting on?
Kind of surprising about the tool holder...where' you get it from?
Is that fellow in back with the hat related to Chip?

Oh...and where are the Crackers?


----------



## vlmarshall (Mar 5, 2010)

zeeprogrammer  said:
			
		

> Did you make that table the lathe is sitting on?
> 
> Kind of surprising about the tool holder...where' you get it from?
> 
> ...


Ha, thanks. The "table" is really just a board like Sherline suggests, nothing special. It's actually louder than I'd like, kinda rumbly.

The toolholder came from A2Zcnc. I sent 'em an email, complaining but not really demanding anything, to which they never responded. No matter, eventually I'll make a steel version of the toolpost and holders.

I expected that the yellow flowery wallpaper would get more attention than the 'robot head' in the background.

Lastly, the Crackers... have their own thread.  
Ok, really, they're sitting on a bookshelf off-camera.


----------



## vlmarshall (Mar 7, 2010)

Well, I've re-anodized the tool holders, and I'm working on setting up EMC to see the spindle index pulse from one of the two currently unconnected cards in that box of electronics.


I'll probably also work on that speed controller card as well...if I feel brave. It's a card from CNC4PC, that replaces the speed control pot with a 0-10v signal under computer control. A year ago I tried using this card on my mill, missed the bit in the instructions about using an ISOLATED power supply, and burned out the motor board in the mill.

Not sure I want to play with THAT again.


----------



## vlmarshall (Mar 7, 2010)

:big: Ha! :big: I just got the software-controlled spindle working. This task caused me much trouble a year ago when I tried it on the mill, only to burn out my mill's motor controller. Tomorrow I'll add a "Manual/Off/Computer" toggle switch to the Sherline's control box, neaten up the rest of the wiring, and calibrate the speed with a tachometer from work.

The last obstacle is the spindle index pulse...


----------



## 1hand (Mar 7, 2010)

Glad to hear your project is coming along great. I wish I wish I was there too, and have the knowledge to know what your talking about. :-\

Sooner or later this will all start making sense........I hope.

Matt


----------



## vlmarshall (Mar 7, 2010)

Thanks!



			
				1hand  said:
			
		

> Sooner or later this will all start making sense........I hope.



It will, you'll see. Get your Gecko, stick some steppers on the machine, everything else will come together one step at a time.


----------



## zeeprogrammer (Mar 7, 2010)

Vernon  said:
			
		

> The last obstacle is the spindle index pulse...



Last obstacle to...what? ;D

Naturally, I've been interested in knowing what the hold up is with my beer.


----------



## vlmarshall (Mar 7, 2010)

zeeprogrammer  said:
			
		

> Last obstacle to...what? ;D
> Naturally, I've been interested in knowing what the hold up is with my beer.



Arrrgghhhh....


----------



## vlmarshall (Mar 9, 2010)

Well, yesterday I got the spindle tuned to within 10rpm of commanded no-load speed, through the 0-3000RPM range. This assembly is going so much better than my mill did years ago. The boards from CNC4PC (breakout board, spindle speed, and spindle index cards) and Gecko stepper-motor drivers are in a completely different class from the old Xylotex system.


----------



## 1hand (Mar 9, 2010)

Vernon  said:
			
		

> and Gecko stepper-motor drivers are in a completely different class from the old Xylotex system.



Better?


----------



## vlmarshall (Mar 9, 2010)

Absolutely better. Not only does the higher voltage (48 vs 24) give more power and speed, but the Gecko has some internal programming called "midband resonance dampening" which kills the high-speed stalls common with other drives. Look on YouTube for Stepper Dampener or such, or I'll post a link here later, and you'll see a Xylotex machine locking up without "harmonic balancers" added to the stepper motors.
I've got 'em on my mill, and it does help some, but it's nothing like this lathe system.


----------



## Tin Falcon (Mar 9, 2010)

When I forst looked into cnc I was very tempted by the xlotech and it does get used sucessfully but I was wisely steered toward the gecko. The xloteck has a rep of being over or maginaly rated and easily gives up its magic smoke. It is rated for 24 volts not 25. IIRC I am running 36 in my gecko .
Tin


----------



## vlmarshall (Mar 9, 2010)

Xylotex has also made a revision, and refuses service (not just warranty, but SERVICE) on older boards like mine. needless to say, I don't have much faith in the thing now. I've been helping my parents build a CNC router for woodwork, and when they got that Gecko 540 I was just plain speechless. 

Speaking of service, each axis in that G540 is a separate card, actually using the a variant of 251's like I now have, so burning out something doesn't mean you've ruined the whole system.


----------



## Tin Falcon (Mar 9, 2010)

> Speaking of service, each axis in that G540 is a separate card, actually using the a variant of 251's like I now have, so burning out something doesn't mean you've ruined the whole system.


That is one of the things that sold me on the 540 and in the unlikely event one does go bad just put the a axis driver in the slot of the offending driver and order a new one . 
Tin


----------



## 1hand (Mar 9, 2010)

Tin Falcon  said:
			
		

> That is one of the things that sold me on the 540 and in the unlikely event one does go bad just put the a axis driver in the slot of the offending driver and order a new one .
> Tin



That is a great Idea if something where ever to happen.

Matt


----------



## vlmarshall (Mar 9, 2010)

I've done that drive swap at work, on the Haas mills. It's great for getting a job out the door in a pinch. Even better at home, where time is more valuable than money. ;D


----------



## vlmarshall (Mar 14, 2010)

Well, it works. After two weeks of struggling with it, I can finally singlepoint threads with this lathe.

The Sample threading program that comes with EMC was pretty rough with mismatched speed and feed, relying on the encoder to sort things out, but by matching the spindle speed and feedrate I was able to get good performance out of it.
Here's a (long, boring) video of my first singlepoint threadcutting with this lathe. After I got it set up, I decided that, good or bad, I was getting it on video. ;D

[ame]http://www.youtube.com/watch?v=C8zwXztmpEc[/ame]


----------



## Maryak (Mar 14, 2010)

Vernon,

Great, I'm very impressed. :bow: :bow: Now if only the NC between my ears would drive my hands like that, as it is, if the breath in breath out tape stops............. I've got a problem. 

Best Regards
Bob


----------



## 90LX_Notch (Mar 14, 2010)

Vernon,

That's very cool. I love stuff like that. I wish I had the funds.
Also, great job with the credits! :big:

Bob


----------



## zeeprogrammer (Mar 14, 2010)

I enjoyed the video.
And I appreciated the 'thank you' at the end. ;D

But seeing as it was you...I should have known.
Since you owe me beer, I've tried to be nice in hopes you'd actually pay up...but now...

"Of course you realize, this means war."


----------



## bearcar1 (Mar 14, 2010)

[quote

"Of course you realize, this means war."


[/quote]


Isn't that what Daffy Duck said to Bugs when he was getting his arse kicked? ;D



Great vid Vern', In time I may have to break down and get mechanized, but for now I;ll have to make due with what I have, *sigh*


BC1
Jim


----------



## 1hand (Mar 14, 2010)

Very nice, and fast too. Great job! Thm:

Looking forward to this even more now!

Matt


----------



## steamboatmodel (Mar 14, 2010)

A great job.
If I may make one suggestion, some thing I learned running commercial CNC. You need to move the start point over from the end of the work so that you are cutting air for about three or four thread pitched before it starts cutting metal. this allows everything to come up to speed and synchronize at the start of each cut.
regards,
Gerald.


----------



## vlmarshall (Mar 14, 2010)

steamboatmodel  said:
			
		

> If I may make one suggestion, some thing I learned running commercial CNC. You need to move the start point over from the end of the work so that you are cutting air for about three or four thread pitched before it starts cutting metal. this allows everything to come up to speed and synchronize at the start of each cut.



Thanks, yeah, I know... This was running a sample threading routine that comes with EMC, and the zero point was...at the bottom of the thread if I remember correctly. Onscreen, it looked like it was going to start threading out where the cutter started chamfering air. ;D I can't wait to start using this thing for real!


----------



## wongster (Aug 2, 2010)

Hello,

I'm in the process of wiring up the G540 VFD to my Sherline's speed control. Kinda of lacking in confidence to do the job though the KBLC board has now been taken out of the box.

Do you have some pics showing how you wire them up?

Appreciate any help.

Regards,
Wong


----------



## ttrikalin (Aug 25, 2010)

very impressive!

t


----------



## kvom (Aug 26, 2010)

Does EMC use a canned cycle for threading?

It looks as if it is increasing the cut depth the same amount each time through. which can be a problem if threading harder material like steel. Optimally you want the cut depth to decrease as more of the tool engages the stock.

Looks like a good system you have there.


----------



## vedoula (Aug 28, 2010)

kvom  said:
			
		

> It looks as if it is increasing the cut depth the same amount each time through. which can be a problem if threading harder material like steel. Optimally you want the cut depth to decrease as more of the tool engages the stock.



kvom, is this because you want the volume of metal removed each time to be the same -- rather than the depth of the cut?

v


----------



## kvom (Aug 28, 2010)

The deeper the cut, the more of the tool tip is cutting, and thus more force. It's like any other turning operation, too large a DOC can break the tool tip or stall the motor. So cutting the same volume per pass is what you want.

For Mach3, G76 is the canned cycle. The H code gives the depth of the first pass, and the control figures the number of passes and depths for constant volume removal up to the Z code depth. EMC may have something similar.


----------

