Hello Guest it is March 29, 2024, 11:02:40 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - DICKEYBIRD

Pages: « 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 »
351
Show"N"Tell ( Your Machines) / Re: A project from a year ago
« on: December 23, 2012, 09:24:35 AM »
Thanks Rich.  I felt silly for spending the amount of time I spent on the MicroMill trying to minimize its weaknesses and REALLY silly about half way through the so called "quickie" add-on lathe project but its uncanny how lucky I've been with my machine building/modding projects.  I've done several machine or tooling projects now for no other reason than to see if it would work or because I thought it'd be cool to have it and might be useful down the road a ways.  Each time, some previously unknown paying job soon comes rolling in that couldn't be done without the thing.  Lucky I guess!

Some of the profits from the roller shaft job were used to procure and fix up a Denford ORAC CNC lathe.  When it's finished, I'll remove the lathe gizmo from the M/Mill and return it to (tiny) milling use.  Can't wait to see what wierd-a$$ project shows up next! ;D

352
General Mach Discussion / Re: CNC4PC C11 question
« on: December 21, 2012, 08:59:36 AM »
Hello, that's kinda like asking what kind of car to buy. ;D

There's a lot of options out there and from what I've read, many of them are very good products.  I bought the C11 because it looked to me like it had the most functions that I needed for my project for the lowest price.  It's now working well but I had a VERY hard time getting the speed control working due to my lack of electronics knowledge and total ignorance of the isolation issue with my KB SCR speed control.  I had to buy a separate KBSI-240D signal isolator to get the speed control to work.

Some portions of the manual were unintelligible (to me) The seller, Arturo Duncan was quick to respond to my questions but I just couldn't understand what he was trying to tell me and I got very frustrated.  I think the prioduct is fine but the manuals need a total re-write in some areas for cuttomers like me that are weak in electronics .  Will I buy another one if the need arises?  Probably so if I'm still on a budget.

Another ORAC owner/retrofitter I've corresponded with uses a Campbell Designs B.O.B and he's very happy with it.  It has onboard power supplies and I think it handles the SCR speed control isolation problem differently.  It is almost twice the price though.

I wouldn’t go with one of the many cheap units you see on ebay and would recommend  staying with an established product that has good support.  You can find a lot of info here and on other sites online that my help with your decision.

Good luck and post lots of pics of your project!


353
Show"N"Tell ( Your Machines) / Re: Denford ORAC lathe retrofit.
« on: December 20, 2012, 12:47:18 PM »
A little update on the ORAC project.  I wanted X-axis homing to be as accurate and repeatable as possible so I installed a N.O. microswitch on the X slide which closes near the end of travel and sends the signal on to the B.O.B when the disc mounted on the stepper shaft closes the opto.  The opto sensor/boards came from the Netherlands off ebay for $7.95 each, free shipping!  I made a pair of plastic mount blocks and the sensors are held in place by a couple drops of superglue.

After a few iterations of microswitch adjustments, the X homing is dead accurate and repeatable.  I can see no variance whatsoever in a DTI attached to the side over many, many homing moves. 









The maintenance guy at work gave me a neat little aluminum weatherproof box so I mounted it to the X slide for a place to put the wiring connections and mount the Z opto sensor board.  I made an adjustable Z axis stop rod holder which allows easy changes of the Z home position.  I didn’t want it permanently mounted at the far end of Z travel to prevent a long wait for the carriage to run all the way to the end then back to the work position each time it homes.  It can easily be reset if a job comes along with long stock.

Oh yeah, another feature is the black nylon screw holding the stop rod in place.  Being the realist that I am, I figure if it over-travels for some reason, the screw will allow the rod to slip and hopefully won’t punch a hole the box before I hit the esc key.





354
Show"N"Tell ( Your Machines) / A project from a year ago
« on: December 20, 2012, 11:47:50 AM »
This project is over a year old but eventually made me a decent size lump of cash.  Here’s some info & pics that may be interesting to my fellow newbies.

I bought a Denford MicroMill off Craigslist for $100 with no software or dongle.  With help from various nice guys on the Denford UK forum, I was able to remove the serial board from the SmartStep3 controller and connect the step/dir/gnd pins to a B.O.B. and control it with Mach.  Once I got the axes moving I went through the thing adding acetal thrust washers to tighten up the slop, gravity feed oilers and brackets to connect the top of the Z column to the enclosure to take out much of the flex in the column.  I also added a counterweight/pulley system to the Z to ease the burden on the puny (80 oz/in) stepper motor.








It worked as good as a tiny mill could but I decided what I really wanted was an option to add a CNC lathe function.  I had enough stuff lying around to cobble up a treadmill motor powered ER32 spindle assy. that mounts to the left side on the mill enclosure floor.  I added rectangular steel tubing bolted underneath the enclosure floor to stiffen it up before mounting the assy. and it’s plenty rigid for the small work I’ve done with it.  Hood just thinks he’s got a “wee lathe....THIS is a wee lathe!







I had removed the treadmill motor’s flywheel/fan to install the drive pulley and was concerned about overheating so I installed a 12V server cooling fan.  I made a plastic duct by heatshrinking a 2 liter soda bottle (P.E.T. plastic) over a homemade wood plug.






 
I made a little toolpost and mounted it on the left end of the mill table and it worked very well for what it was.

Coincidentally within days of getting it running, a neighbor/friend down the street asked if I could repair some roller shafts for him and the company he works for. The shafts were manufactured by one of their vendors and are beautifully made from 303 stainless covered by a precision ground rubber cover. The problem was that that the shafts were snapping off at an e-clip groove after being in use for a while. The bottom corners of the groove weren’t made with the specified radii and the sharp corners created a stress riser and the shaft eventually fatigued & broke there. My task was to remachine the groove using a wider tool with larger radii in the corners to blend into the “floor” of the groove, taking a minimal amount off the diameter.


The shaft had to be chucked by an aluminum sprocket on one end and fortunately was small enough that I could make a thinwall acetal bushing and chuck it in a 3/4” ER collet.  The other end of the shaft had to be restrained by a tailstock.  Mine had no tailstock so I had to make one that bolted to the floor of the enclosure on the right side and straddled the mill table.





Once the shaft was chucked up, I realized I could barely see the groove much less the .0075” specified radii in the corners or the bottom of the groove.  I mounted a cheap USB microscope to the machine so I could see the groove & tool alignment and set the depth of cut properly.  Here’s the view through the scope.  To give a bit of reference, that shaft is ¼” dia. And the Kaiser thinbit carbide tool is .021” wide.





Unfortunately the close up view with the shaft turning revealed the groove wasn’t concentric with the shaft or the sprocket so I made a D.I. tip with a .015” blade to reach down into the groove to accurately measure the runout of the bottom of the groove.  The runout tests made me a bit queasy as I found it was different on every shaft and I realized every one of the 1060 shafts would have to be dialed in individually before making the cut!

 I decided I would have to make an adjustable (poor man’s set-tru) ER32 chuck that would both do the job and fit into the tiny bit of real estate available in my little machine.  I wasn’t confident enough in my skills to make a new spindle from scratch so I sacrificed an ER32/R8 and a ER32/MT2 collet chuck to make it. I cut them apart and added 2 interference fit flanges with a raised boss on one and a recess in the other to allow the 4, 6-32 brass-tipped screws to adjust the shaft into place before the 4 nuts are tightened. I turned a press-fit sleeve to go onto the end of the R8 shaft so that I could single point the 1 1/8-18 TPI thread to fit the preload ring nut and turned & polished a 30 mm journal to fit the pulley end bearing. The R8 taper was turned down & polished to fit the other bearing.





I used the mill to assemble the shaft and ER stub to the pre-heated flanges to insure proper alignment.  The .002” interference fit holds the parts together well.











It worked great and allowed me to chuck up the shafts & dial in the groove bottoms to .0002” to .0005” runout even though some of them were slightly D-shaped.

Here’s a pic of the rig in use.  I became very familiar with this view over the 4 months of spare time it took me to modify the machine and finish all 1060 of the shafts.








355
Show"N"Tell ( Your Machines) / Re: Denford ORAC lathe retrofit.
« on: December 14, 2012, 08:56:21 PM »
Thanks Dennis, glad to hear from a fellow ORAC owner!  A good little machine methinks. :)  Haven't done much real work with mine yet but it's getting there.

What kind of tool holder setup do you have?  QCTP or gang or??  Got any pics or a link to a thread?

356
General Mach Discussion / Re: Now the Orac is 90% done, mill next!
« on: December 13, 2012, 01:22:13 PM »
Cool, another ORAC'er! ;D  Mine's about 95% I suppose but the last 5% is a pain.  Here's some pics of what I did to mine. http://www.machsupport.com/forum/index.php/topic,22258.0.html

I've added homing switches and some other stuff since that thread; I guess I should update it soon.

Show us some pics of your project...I luv pics!!

357
...maybe when I get the wee lathe up and running fully I can, big lathe is just too big to be able to set up a camera for that.
Yes please...show us how you set up and use your tool table too!:)  You make it sound so easy and I'm sure it is once one gets "over the hump."

358
I have a few good quality switches that I can install on my machine. I should do that.

When I turn on the machine, I could home x and z and then the machine will know exactly where the cutting points of the tools are correct?
Definite yes IMO on the switch issue although I'd go with optos instead of mechanical at least on the X.  I went through 3 (what I thought were) "good quality" mechanical switches before getting one that was reasonably consistent.

Yes on statement 2 except the machine will know exactly where your SWITCHES are but won't know where the tool tips are until you set them up.  That's where my knowledge ends as of this time.  I'm still trying to get my head around the tool table and offsets.  I have established where the spindle center is via cutting a piece of stock, measuring the dia. and using that to MDI to the center and then zeroing the X DRO.  Works great for that tool but will have to set up the table for other tools before it becomes really useful.

edit: oops, Hood posted before I could type this so dunno if this helps or not.

I'm slow but I'm old so I have somewhat of an excuse.;)

359
I don't have homing/limit switches on my other little lathe and grew tired of having to constantly reset the X-axis zero point and get it to cut consistent diameters without fiddling around a lot.

I spent the nec. time to install & config opto sensors on X & Y on the ORAC and am real happy with the repeatability of referencing on the X-axis now.  It's worth the time & effort in the long run to know that it's going to cut the same dia. with the same tool each time I turn it on & re-reference it.

360
Hey Nate, see if this helps http://www.cjh.com.au/Gang%20Tool%20Block%20Offsets%20for%20CNC%20Lathes%20under%20Mach3%20Control.pdf  Kind Mr. Chris Humphris did a fantastic job of documenting the process that works for him.

I'm getting close to setting tool tables up on my ORAC retro and RTFM'ing and searching on the forum still has me dazed.  I printed the sections in the manual that deal with homing & tool tables/offsets and I read it during lunch at work almost every day.  I guess I'll try wadding the pages up and eating them next.  Maybe that'll work. ;D

Pages: « 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 »