[Fixittt]

Machining wax, while not machine intensive you need to make sure that for jewelry, you have good resolution.
For a long time now my 4th axis has just been a stepper motor with an arbor on it. It worked, but was not very rigid. And getting things setup was a pain in the rump.

As I am more of a DIYer I didn't want to drop the $300+ for a sherline rotary table. Mainly because I dont have the $$$ to spend. So I picked up a cheap Chinese manual rotatory table. Studied it and found that the run out was really high. Took the sucker apart and found that the only vertical support was the small shaft that the face plate is part of. Towards the rear of the table, this shaft fits into a thin bearing and is pulled tight into place by a short bolt. There is NO internal front face support what so ever! Using the big manual lathe as the shop I made a step and a brass bushing. The brass bushing press fits around the inside of the face. The step was turned into the baseplate and everything fits night and tight now. It still spins free and has frontal support.
The handle on the rotary was pulled off and again with some lathe and mill work I made a stepper motor adapter. Its long and looks a little odd but it works great! I now have higher resolution on my 4th axis for machining rings. Now I just need a way to hold my wax for machining.

Well, I solved that problem as well. Using the manual lathe again, I made a adapter that bolts to the face of the new rotary table. There is a .998 bore in the center to receive different types of fixtures for the mill. I wanted to make something that was a universal fit. Undo a set screw and pull the fixture out of the receiver, and slide a different fixture in. Tighten set screw.

I am very very happy with the way these came out. Very smooth fit. And after spending about 3 hours getting the new table indicated in and the receiver plate zeroed onto the rotary I have only .005 in run out at the very end of the ring arbor. VERY VERY PLEASED!!!

Here are some pics of the whole ordeal.

[Fixittt]

pics of the new fixtures in use

[Lexx0001]

Interesting. I like your idea of using dryer venting for the cooling intake of the spindle motor. I think that would work better then any filter material. One question, what are the white attachments on the end of the stepper motors? Are they encoders? I know a Ol doesn't have them, but you've done so much work, I wondered if you added them.

I've got a 10-CL, and I'm scared that the motor controller will bomb out for me too. If it does, I think I'll go a similiar route and buy a different controller.

[rowbare]

Lex, those are the rattler dampeners that he spoke of in post #20

[Fixittt]

They are dampeners Like rowbare said. And they work great!

Also what you dont see about the dryer hose is that it goes up to the top of the box where I have a 120MM 110V fan blowing into the hose to supply the motor with cool air from outside the box. And on top of the fan I have a K&N Cone style car air filter filtering the dust from the room to keep it out of the motor.

[Fixittt]

With the new fixture system in place I was very pleased with the surface quality of my waxes. This setup is great. Then today I found myself in a situation where I needed some way of doing a necklace pendant with something on both sides. I need a good flip fixture.
I make my own wax slabs. So I wanted my fixture to be just for these wax slabs that I melt and mold.

So off to the machine shop we go........ and a few hours later there is a new addition to my fixture setup and man is swapping out the ring arbor to the flip fixture such a breeze!

Here are a few pics

[Fixittt]

More updates on the MAXNC project.
I found that the stock spindle was for lack of a better word. "CRAP" with .002 thou run out at the taper inside the bore of the spindle. This would translate into .015 thou inch if I had the tool extended from the collet a considerable distance. With this runout I was loosing detail in my wax models at an alarming rate. If I programed something to use a .005 tool tip the cut would be over .010. I saved and saved my pennies. I finally was able to purchase a "WOLFGANG ENGINEERING" double bearing spindle. http://stores.ebay.com/Wolfgang-Engineering When it arrived in the mail I was amazed with this thing. It is his entry level spindle. I made a request to get mine fitted with the ceramic bearings and he was wonderful about filling my request.
So I now have this awesome spindle in my hands. But I had no way of mounting it to my machine. So I took the head off the machine and headed to the machine shop. Taking the head apart. I measured the OD of the bearings on the cartridge spindle. I got on the manual lathe and made me a spud that was the exact OD of the bearings. I then bored a hole .002 over the 3/4 in diameter of the new spindle. This was a press fit. I didnt want to press it in. So I polished the center bore with sandpaper untill the spindle would slide nice and tight into the hole under a small bit of pressure. I wanted it to be removable. Next taking the spud to the CNC mill I measure the 1/4-32 holes on both sides of the original spindle that clamps the 2 halves of the head to the cartridge. Drilled and tapped these holes. Next I needed a way to keep the outside sleeve of the new spindle from possibly rotating inside the spud. A simple set screw worked fine. Drilled and tapped this hole. Then came assembly. (Dont worry the following pics show the steps of assembly. This setup kept me from having to re-invent the wheel so to speak. I used what I had and used my original motor to drive the spindle.
After tramming the head and getting it within .0015 thou I was ready to try the setup out. It was 4 times quieter then the original spindle setup. And I was using the original motor. I was also able to machine my rings on a rheostat setting that would not even spin the original spindle. I am very please and at a little over $150 shipped I couldn't beat this!

EDIT in the last two pics of the run out. Please note how far out the tool is from the spindle while being measured. Yes the needle did move a bit. compare the pics. at this length outside the collet I was getting close to .015 on the original spindle.

Second EDIT. I was asked by a friend what the black stuff is on the sides of the head. That is the anti-vibration matting used in car audio setups to keep things from vibrating. (Dynamat) I was noticing some high frequency vibrations caused by the Dayton spindle motor. Applying the Dynamat to the sides of the head absorb this vibration and the machine doesn't resonate inside the enclosure like it used to.

[Fixittt]

After machine my first rings with the new spindle I have found that the surface quality of the wax is SUPERB!

This wax was cut with a
15 degree .005 tool tip
650 mm a minute feed
oil based drip coolant

The machine is 4 times quieter now. I m running lower motor speed then before and the wax is coming out beautiful! I am very pleased with this new spindle. It took me a few hours to devise a holding solution for the spindle but I must say it has worked out very well.

Pics of the wax. I did not take the time to clean them good I was more interested in surface finish.

[Lexx0001]

I can't be certain, but it looks like you've actually geared up the spindle. Overdrive, as it were, with the spindle rotating faster then the motor?

Looks like maybe you aren't using the original belt either. Is that a O-ring?

I've noticed on my own machine that the spindle seems to turn with a lot more force then would be ideal.

[Fixittt]

yes the is a gear change involved I havent done the math to find out what gear ratio its running now. im guessing at full speed its some where around the 17000 RPM mark.
Im the pics an o-ring is on the pullies yes. But I noticed that at high RPM`s the o-rings would flare outward. So I put the original belt on and slid my motor WAY back. As I have a dove tail designed motor mount.

One mission I will be on is to find a shorter belt.

[Fixittt]

LOOKEY LOOKEY something new.So pics and a short video of the flip.

[ame="http://www.youtube.com/watch?v=sOru6KwCZBo"]YouTube - MAXNC flip fixture[/ame]

[Lexx0001]

You mentioned having to tram your spindle. How did you go about doing that? Shims under the Z column or loosen everything up, square it, then tighten?

I've got to do something with mine, the table travel is flat and my Z axis travel is square but my spindle isn't. I've been trying, just haven't been able to see any positive results.

[Fixittt]

some short videos I made on the subject.
You want to get it square front to back fisrt. I had to install shims under the the bottom part of the head. Once you know what it takes to get the head straight top to bottom, then you can loosen things up and get it square left to right. THen slowly tighten each bolt. Also a side note. I put washers (not in the video) under the heads of the bolts because the soft aluminum tends to pocket. Creates indentions under the head screws and makes getting things lined up harder.
http://s122.photobucket.com/albums/o...mmingpart1.flv

http://s122.photobucket.com/albums/o...mmingpart2.flv

[Fixittt]

Update. Setting Z height.
When working with ARTCAm and many other jewelry specific cad/cam softwares, the Zero points for X,Y, and Z are in the center of the models drawn. This translates into the center of the wax. Unlike conventional machining where you set the Zero points at a corner and the Z is set at the top of the material to be used.
Finding Z zero is a critical item. X can be close its a non critcal zero point as long as your wax extends past both sides of the model being drawn. Y is also a very critical setting, but that is not what this post is about right now. (Will cover that later)

So imagine that your Z zero is dead center of the WAX. Not really the wax. but in the dead centerline of your rotary.

Moving right along, I received a Z axis probe from a good guy that I am helping with his mill. He said that when he received the probe form another guy and he tried it it blew his driver board. RED FLAGS! When I got the probe (Basically a digitizing probe with a flat bottom and table top) I checked it with my ohm meter for continuity. I got nothing. Pulled the probe apart and checked the wires. They were solid. Taking the probe completely apart I found corrosion on all touching surfaces. Taking a fine grit cratex wheel I went to polishing all the surfaces. After polishing up the 6 small balls, the coper circuit board and the brass barrels. I put it all back together and checked it again. This time I was getting a reading on the ohm meter. And when I pushed down on the small table top the connection was broken. So I wired it up, messed with Mach 3 VB (With help from some friends) and got it working and dialed into the centerline of my 4th axis.

PIcs and short video to show its operation.

[ame="http://www.youtube.com/watch?v=HeO_gCAH3M4"]YouTube - Tool height probe[/ame]

[Lexx0001]

Just a FYI, I'm continuing with the tramming of my machine. Thanks for the videos, I appreciate it.

I wonder why the digitizing probe blew out your friends board. I would think that an open wouldn't cause any harm. I mean, it wouldn't work, but It's basically just a switch that doesn't close. Unless there was a short from +V to ground, but there should be a pull up resistor in there somewhere.

[Fixittt]

my guess is that with all the corrosion ect. The contacts were so intermintant that it was causing resistance or something. With a probe you do not use a pull up resistor. It is wired straight to the printer (LPT) port. Unlike limit or home switches.

[Fixittt]

Its been a while so I will do a short update.

I had a problem with the wolfgang spindle one of the bearings locked up and it smoked my spindle motor. I contacted Wolfgang engineering about the spindle locking up after 3 weeks. He took care of the problem very quickly and it wasnt long before I had a new spindle in hand. Its service like this that makes for a good vendor and he will get repeated business from me in the future.

I have since been using the motor that he sells on his ebay site. Its a great little motor! I didnt think it was up to the task, but its awesome. I am about to order a spare motor to have on hand. For the money, his stuff is WELL WORTH IT!!!!!!!! I highly recommend and praise his work.

I have been becoming more and more comfortable with the mill. A few things I have noticed. If you tighten the gibs to tight you will increase your backlash. So keep them adjusted and a bit loose.
My backlash nuts do not like to be run dry. They squeel. So I keep them lubed with some medium weight hobby oil. Im about to switch to 3in 1 oil.

The machine after being trammed in and a good spindle has been producing some very good wax`s. But the gib adjustments are a pain. Also I am about to move my A axis inwards about an inch as I notice that I am wearing the gibs uneven.
I also had a major problem with my X axis stalling on me in a very predictable manner. I spent 3 days chasing the problem. COme to find out I had my A axis motor tuning settings in mach3 way way way to high. After bring the motor tuning down to a relative same speed as the other axis`s the problem cleared up. FYI!

Anyways here are some pics.......

[toneV8]

Fixittt: when you make ring or anything else in wax then what, how do you make it in gold or silver. Can you describe process maybe with pictures.

[Fixittt]

Tone, i will do my best to describe the process.
Its a process called Lost wax casting. I dont have any pics of the wax process. But what you do is.

melt on a spru. This is simply a wax rod to somewhere on your wax model. Weight each peice after you put your sprue on. This comes into play later. You can build what is called a tree. The tree is built on a rubber base. The sprues are all melted to a hum on the rubber base. And you build your tree. think of it as your hand. with short fingers sticking up. at the end of these short fingers are your wax models. When you get your tree built up. You put a metal flash around the tree which seals to the rubber base. So now you have an enclosed flask with an open top with all your wax inside it. Mix up a type of plaster investment. Once this is mixed you pour the investment into the flask covering your wax models in plaster. While the plaster is still wet you stick the flask on a vacume table. You vacume all the air bubbles out of the plaster. after all the air is sucked out of the investment it is set aside to harden and dry out. Once the plaster is hard and dry you pull off the rubber bast that you originally melted the ends of your sprues to. When you look at the end after the rubber top is pulled off you will see the wax rods that are your sprues. Next is a burn out cycle. This cycle is a long process with ramping of the heat in an oven. What this does is melt out all the wax leaving an exact negative of your wax models. Once the temp is ramped down to certain temp and left to stabilize the flask is removed from the oven and placed on a spin casting machine. Remember the weights of the waxes you put in the flask? You take the total weight of the wax and use a math formula to determine the amount of metal you need. in the center of the spin casting machine is a bowl that has a direct connection to the plaster hole in the flask. You use a torch to melt down the metal and once it is hot and molten you release the spin casing machine and it spins using centrifugal force to fill the plaster flask. After the flask is allowed to cool a bit to alloy the molten metal to harden the still hot flask is submerged into water where the hot plaster basically explodes off of the medal. Pick the plaster off the metal and cut the sprues off and start the finishing process.

[pete from TN]

I always knew about the lost wax process but seeing your setup and machining the wax on your homebuilt mill to these tight little tiny little intricacies on the wax molds is really interesting. Bravo man and I really like the looks of that ring in the previous picture. SWEET and nice work on the mill and for not a lot of money invested. Peace man....

Pete Matos