Planning Project Gunner: CNC done, back to the case design (2/19/2016)

Been a long time...

I have been working on converting the mill to a CNC since last time I posted and it has been a long haul. The learning curve is crazy and I am still working on it. I just going to post up some pics so you can see where I am at and where I am headed. Still have a long way to go, but I am about six months away from cutting metal with it.

I made a work bench (took two tries):









Ripped my mill apart so I could measure everything, lapped the ways, and converted the spindle to an R8 taper, so tooling is cheaper:







I did a three bolt head mod to increase rigidity of the mill:





Came up with an overall design concept:



Had the mill stand and tub made:









Got the stand and tub powder coated:





Got some of the parts made (more on their way):





And just finished designing all the components for the first phase of the conversion tonight (minus the control box, pneumatic draw bar, and motor upgrade):










So that is what I have been up to. I didn't want you guys to think I had quit...things are just taking longer than I though

 

Bad *ss. The rolling table is a good idea.

 

Thanks Cheapskate I can't claim the idea. I saw someone else do it, but the casters are cool; they have rubber feet that screw down and lift it off of the ground so it won't move once you get it where you want it. They are called "leveling casters" if you ever want to get some.

 

Two updates in one:

First update:
I thought I would give you guys an update. I got the mill modded to add the oil groves. On the z-axis carriage I drilled three holes from the top (that is where the oil lines hook-up. Then I drilled a hole on each side to intersect with the outer two holes coming from the top. I then drilled holes on the back to tie all the intersecting holes together. This seemed like a clean way to get the z-axis oiled; it also lets me oil the z-axis ball nut. I had to machine the front of the column a little higher to accommodate the fitting that will be on the back side of the z-axis carriage. The hole for the fitting is right above where the ball nut mount attaches. I used a similar approach for the saddle. I drilled two holes on the front and back of the saddle and then drilled down from the top to intersect the holes. The oil fittings mount in the three holes in the middle of the saddle where the holes for the ball nut mounts are. The last pic is of the parts I just got from Scott. The parts are my ball nut mounts, z-axis pillow block mount, oil manifolds, and one of the parts for the limit switch system that mounts on the saddle using the existing M6x1 holes. I ran into a little bit of a problem with the ball nuts I got through homeshopcnc.com. The dimensions of the ball nuts do not match the spec sheets they have posted on their website. I have already had the x and y-axis ball nut mounts remade and now I have to have the z-axis ball nut mount remade, which really sucks. In the next couple of weeks I am going to start assembling the mill and building the control box, so things are starting to get exciting.

Z-axis carriage with oil groves machined:





Z-axis column with top machined higher:



Saddle with oil groves machined in:



Machined parts for the mill:




Second update:
I have been test fitting parts and working towards getting everything assembled. While I was doing that I managed to dump the balls out of one of my ball nuts. It turned out to be a good thing. I learned how to repack a ball nut (not as hard as I thought) and I got to clean it out. I am not sure why but the vendor did not completely fill the nut with balls, so I ordered some extra off of ebay and I am going to clean and repack my other two ball nuts. One other thing I did was drill a 5/16” hole in my y-axis gib for an oil passage. I think I am going to need to make the hole a slot. When I installed and marked the gib for the hole I drilled, I used oil, but when I reinstalled it I used grease. For some reason everything fits tighter with grease and now the hole does not line up as well as I would like with the oil inlet. Here are pictures from the silliness.

Mounting pillow block to ball screw:



Mounting first y-axis part:





Mounting second y-axis part:





Gib with 5/16" drilled hole:



Saddle mounted:





Oh, after the oil groves were machined in the saddle I had to come back and take a razor to the edges of the groves to take the edge off of them; they were shaving material off of the ways.

I should start building the control box in a couple of weeks, which I think will be a little more interesting to you guys.

 

Nice work on the case design, but have to say, I luv the mods to your BF Mill more

I have a BF46 Vario sitting here on its stand, ready to be cnc'ed. Need to find the time though, blah...funny enough, I used the same type engine hoist to get that mother on its stand....was a big job.

Will bookmark this, keen to see how you go with this!

Cheers,
Beano

 

Nice! The BF46 is awesome; I wish I had gotten that. I got this BF20 because I wanted to be able to lift it without an engine hoist, but had to get one to lift the lathe

One thing I have realized by doing this is you get a better return on your money the bigger the machine you convert because the cost of the conversion does not increase proportionally to the size of the machine, so you are in a good position

Just so you know Optimum offers a conversion kit for your mill. I think you would save a lot of money/time by using it. Here is a link to a re-seller:

https://www.machinetoolswarehouse.com/xcart/product.php?productid=16333&cat=323&page=1

 

Cheers for the feedback and Link, Mate - yeah, I was aware Optimum has a kit for it.....will still consider it, but may DIY it too.....

Will follow yours with keen interest g/l!

 

hi there,

was wondering if you could post some specs on that bench you made, please



want to get me one going and just came back from checking prices on some wood

must say, those machines make me drool

 

It is mainly made from 2x4s and the top is made from two sheets of 3/4 MDF glued and screwed together. When I get home in a week I will measure the bench and let you know the dimensions. I am very tall, so you will not want to make it as tall as I did. I think 30 inches is a good height. I also put Formica on top and wrapped it in 1x6 pine board. The Formica is easy to apply; you just put a coat of glue on the Formica and the table top. Then lay down some small diameter dowel rods on the table top and put the Formica on top of that. Then take a roller and as you role the Formica down remove the dowel rods as you move down the table length. This will make sure you don't have any air pockets.

 

Plugging Along

I am out of town right now but the last couple of weeks I connectorized my stepper motors, painted the mill base and column, and mounted my new electronics enclosure.

I bought the connectors off of McMaster. The pins crimp on the wires, so not sure I would recommend these unless you have access to a crimper, which run around $168 or you could always solder them. I wish I had not of run the heat shrink so far up the wires because now they are stiff and also putting some nylon sleeving over the loose wires would have been a good idea.

Painting the column and base went way better than I expected. The Rust-Oleum primer with body filler sanded really well and let me smooth everything out. I used a total of two cans of primer for the column and base. I used one can each of gray and clear coat for the column and base. I am not sure how the paint will hold up to the cutting fluid but right now it looks pretty good

I had a new enclosure made which turned out to be cheaper than the Hoffman box I bought. This will give me all the expandability I will need. The other reason I had a new box made was because I dicked-up the old box trying to punch all the holes in it I needed. On the new box I made the front and rear panel removable so I can update them easily and everything will mount on din rails.

Connectorizing the nema 23 motors:



Sealing the connectors against water with heat shrink:



Connectorizing the nema 34 motor:









Priming the base and column:



Final Coat:





Match drilling the new control box:



Control box mounted:



When I get back I am going to get the enclosure powder coated, chem film the electronics panel, and hard anodize all the other parts. Then I will start putting everything together

 

Small update

It is time for another small update. I have started putting things together. I have started assembling the base and running the oil lines. I have a little bit to wait before I get the rest of the parts I need, so I was thinking about using copper lines instead of the ones I used in the picture…thought it would look cooler and be more durable.

Pic of most of the parts hard anodized:



The tub and base mounted:



Running the oil lines:

 

Still Going

I have been slowly working on the mill while I have been waiting on parts. Initially how I routed my oil lines did not work. When I put the table on it was rubbing on the lines—not a lot of room under that table. So then I got the bright idea to try and run copper lines. I spent about 10 hours and almost 6 feet of copper tubing trying to get it right, but still had problems with the table rubbing on the lines. Mainly the line coming from the y-axis ball nut was the issue. I gave that up and switched back the flexible lines and had everything right in about 3 hours.
Another issue I had was there was too much slop in the x-axis ball nut. This was my fault; I dorked up the old ball screw and had to get a new one, so the ball nut was not fitted to the screw anymore. I fixed it by going from .1246 diameter balls to .1247 diameter balls.
One of the last problems I had was an alignment issue with the y-axis. When I repainted the mill I put a healthy coat of paint on it and this caused the y-axis mount not to sit flat and was making it harder to turn the ball screw when I tightened everything down. It took me a bit to sort it out, but I ended up just sanding all the paint off of the front of the mill. The surface was surprisingly flat underneath with a good finish.
Finally this is something I am still working on; the table is binding at one end of its travel, so I need to sort that out before I can move on. I have also found some things with the mounts I have designed which I wish I would have done differently. I will fix them later on. All in all though I think everything is coming together.
When I get back from the holidays I should have the rest of my parts in so I will assemble the z-axis and start wiring up and testing the electronics.
Oh, one last thing, I bought a 1.1KW BLDC motor and driver from Skyfire CNC. There is a picture below of him testing it before he sent it. I have not gotten it yet, but when I do I will post up some more info—pretty excited about it. This should be a good solution for the stock spindle motor and will let me use a regular power draw bar because the motor is not too big. I almost went with a 1.5KW motor, but I did not want to have to change my control box design to accommodate 240 VAC.

X-Axis ball screw in place:



Final oil line routing:



Left side with table on:



Right side with table on:



Front ways cover on and limit switch mounted:



Wasted copper tubing:



New 1.1KW BLDC spindle motor and driver from Skyfirecnc.com:

 

Another update...

I have been putting a lot of time into the mill these past few days so here is an update:
I revisited my spindle. Initially I had over tightened the bearings when I assembled it and it was running extremely hot. I thought I had ruined the bearings, but luckily I didn’t. I took the spindle back apart, cleaned out the old grease and reassembled it. Before I did I sanded the mounts for the bearings a little bit so the fit was a little better. This time when I tightened everything up I did not crank on it. I ran it for 30 min at 1250 rpm and it was only warm to the touch.

While I was working on the spindle, I looked at switching to angular contact bearings, but I decided against it for the following reasons:

I would have half of the dynamic load rating I get with my current roller bearings

I already switched to SKF bearings (got them through MSC) which I can safely run up to 8000 rpm.

Here are the links to the bearings I got:
http://www.skf.com/skf/productcatalogue/Forwarder?action=PPP&lang=en&imperial=false&windowName=null&perfid=131000&prodid=1310002005

http://www.skf.com/skf/productcatalogue/Forwarder?action=PPP&lang=en&imperial=false&windowName=null&perfid=131000&prodid=1310002007

It seems like the real limit to spindle RPM is the large bearing in the head of the mill. The bearing model is a 6209Z. McMaster Carr shows they have this bearing and it runs up to 11000 rpm but that is a load of crap. Shielded bearings get de-rated for speed because they do not dissipate heat as well. I have looked at a few different MFG websites and the best I can find is 7500 rpm max for that bearing.

The bearings that came with my mill are made by a company called CSC—not sure if they are any good, so I may replace them. I don’t want to pull the head apart twice.

I got a bunch of parts from Scott at benchtopprecision.com today. Part of what I got from him was a belt drive kit, which is awesome. It is a good complete solution.

I got the front panel for my electronics enclosure, which I need to powder coat. The front panel only cost me $50 to have it made. I feel like that was supper cheap for the work the sheet metal shop put into it. I was very happy when he gave me the quote. Now all I need to do is finish the rear panel and I can get electronics enclosure put together.

I actually dusted off my lathe and turned down some hex threaded standoffs to make some nuts to retain the bearings for the limit triggers. It felt good to make something I could use. Really looking forward to finishing this mill

Another thing I worked on is doing the final assembly on the x -axis. This just entailed mounting the left side end plate where I wanted it, loosening the screws that hold the x-axis ball nut and driving the table back and forth with an electric screw driver. This made sure the ball nut was lined up properly. After that I tightened the ball nut down, I drove the table all the way to the left and mounted the right side plate.

Tomorrow I am going to start assembling the z-axis. First thing I am going to do is repack the ball nut and make sure all the balls are there and then drill a hole in the gib strip. With that done, I can get it put together.

So here are the pictures (sorry for the long narrative):

Underneath the saddle right before mounting the right side plate:



Trying to reuse the bearings…maybe:



Z-axis manifold with check valves:



Bearing retaining nuts:



Parts I got from Scott:



Assembled limit triggers:



Test fitting the gas shock mount:



Limit switch mount and oil fitting installed:



X-axis stepper cover mounted (got the idea from Tormach):



Y-axis limit mount:



Front panel to my electronics enclosure:



Starting to put together my electronics panel (I made din rail mounting plates for everything):



Belt drive kit from Scott:

 

I'm totally envious. I'd love my own DNC rig.

 

If you are really interested check this guy out:

http://www.skyfirecnc.com/picshow.asp?id=13

Best deal for the money I have ever seen.

By the way I really like the designs you have been coming up with--very creative and original. Also glad to see you are making one

 

I got the z-axis put together and I got the column mounted to the base. Getting the compression fitting and the oil line ran to the ball nut inside the column was a SOB. I started work on it about 1:00 PM and finished at 3:30 AM, but I got it installed It was a stretch goal and I almost gave up. For the oil line that runs into the ball nut I turned down a zerk grease fitting to hold it in place and then put some super glue on it (only thing I could find that late at night). The tail stock on my lathe is so far off that I bought a MT2 tapered tool holder for my AXA QCTP and I have to say I am very happy with it. It lets me accurately locate on the center of a part.

One concern that I have been wrestling with is how to cover my cables. I bought Amphenol RT360 connectors off of McMaster and was feeling good about what I was doing, but then I started thinking about hot chips eating into my cables over time. I think I have come up with a good solution. I am going to by some continuous-flex nylon conduit off of McMaster and the associated bulk head mount 1/2 NPT fittings, rout the cable through it and then make an aluminum adapter that lets me screw the conduit fitting into the back of it and then screws onto the back of the connector head, so essentially I am making a back shell that lets me make an armored cable. Plus, it is something I can make on my lathe. I am not sure that is easy to follow but when I post up some pictures in 3 or 4 weeks (going out of town) it will make a lot more sense. I am really happy with this solution because it solves my problem and I still get to use the parts I already bought. As Charlie Sheen would say “Winning!”
Another thing I am starting on tonight is the design for parts that go on the head of the mill, which is basically the pneumatic cylinder for the automatic drawbar, the spindle top hat, the drawbar itself, and mounts for everything. I think I am going to buy Hosse’s plans (g0704.com) and make a hybrid between his cylinder design and another one someone did for an Little Machine Shop SX2. I think Hosse’s plans are worth it just for his design of the drawbar, which would take me some trial and error to get right. I will be doing the design work at night while I am sitting at the hotel when I am out of town.

One other thing that has turned out really well which I was worried would be a waste of money is the cable routing bar I design that mounts on the back of the mill. It is allowing me to mount a bunch of stuff I had not planned on needing besides just tying the cables to it as they route up the column.

Anyway enough typing, here are some more pictures of the progress:

Drilled my gib strip:



Repacked the ball nut (used grease and a craftsman ice pick like tool):



Ball nut:



Turning down a zerk fitting:



Finished fitting:



Test fitting everything together:



Everything installed:



Motor mount installed:



Column mounted:

 

Slow and steady

Been a long time since I have given an update, so here it is. I am almost done; I just need to upgrade the spindle motor and add a pneumatic draw bar, which I am working on. I can now make my own parts so everything just got exponentially cheaper.

Mill pulled apart:



Connectorizing limit switches:



Installing the belt drive:



















Installing limit switch on the y-axis, dressing and grounding cables:



Limit cables and oil lines installed and dressed in:









Y-axis limit cover installed:



Z-axis stepper motor grounded:



Front stainless steel chip guard installed:



Working on tramming:





Everything setup and ready to make first part:



First attempt at making a vibration dampener for the spindle (laptop went to sleep):



Success:



Air cylinder for pneumatic draw bar:



Design for new spindle motor and pneumatic draw bar:



So after I finish this upgrade to the mill, I am going to start designing a new computer case with components I can make on the mill; it is about time It is going to be a mini-ATX case and I am going to make it as small as possible. I am going to integrate the water cooling into the side walls of the case which will have fins milled into them and act as reservoirs. Looking forward to this.

 

Starts out with concept design of case, re-designs case to suit new desk, decides to build machine shop to build case..

Buys mill and converts the mill to CNC, then decides to re-design the case.

Lol!

Love it all

 

Thanks Nexxo I am in awe of your current project and the parts you are making by hand on your lathe