[alan_3301]

Hi, I plan to document some of my build and post a few pictures.
I've been meaning to bring my camera to work to get some pics, hopefully this will help me remember to do it.

I already have all my parts, I got the hardware only kit, and the diy nema 34 kit.
my 3060 gantry came bent, so I am waiting for another to arrive so I will have to disassemble a little bit, and I'll take pics along the way.
Don't get your hopes up yet, I only get a couple hours a week to work on it, so it may be a little bit before I have something to show.

[vtx1029]

bent 3060? wow!

I hope to finish my wiring enough this week to get some movement out of my crp 4848. :cheers:

[alan_3301]

I got my new extrusion, put it on and took a few pics.

you can see how the extrusion was bent in one of the pics, and the resulting gap on one of the bumpers. I was also able to get the Y axis mostly put together. Everything is going smoothly so far.

I kept the bent extrusion, will try to cut it short and maybe use it as a bed for a small lathe.

[alan_3301]

I thought I'd give a little background
I built my 1st cnc, a hotwire foam cutter in 2005 to assist with lost foam aluminum casting projects. cheap drivers and 1/4-20 leadscrews were the way to go back then. I had no idea 12 ipm was slow. Played with a sherline mini mill for a while, then started building routers. I wasted a lot of money and metal trying different designs, mostly using vxb linear shafts. When cncrouterparts came out with the rack and pinion system, I knew I had to have one. Luckily I came across a manufacturing company closing up, so I was able to buy ~150 feet of metric 4080 extra light extrusion, along with many fasteners and hardware, and a lot of other cool stuff for very cheap. I managed to get it all together with the metric stuff, only buying a 3030 gantry and 1530 z extrusion. I sold it recently, so time to build another!
a couple pics of that setup, then its all crp4848 from here on.

[vtx1029]

I like how your gear rack mounts. Cleaner then the rack clamps. If you don't mind me asking what did that rack cost.

[alan_3301]

those racks are from fineline automation.
I do like the rack clamps, but the racks I've gotten from mcmaster were hit or miss. they are $60 each plus $20 or so on bolts and tslot nuts.
quite a bit more money than the other route, but I like them.

[kinghong1970]

I like how your gear rack mounts. Cleaner then the rack clamps. If you don't mind me asking what did that rack cost.

+1

so the FLA109-01 rack from Fineline automation works with the rack and pinion assembly from CNCRP?

[alan_3301]

I was doing a little checking/maintenance yesterday and realized I forgot 2 important steps when I put everything together.
I never greased the Z axis thrust bearings. Oops! They were sounding nasty. Luckily with grease they are nice and quiet like they should be.
Also I had never checked spindle runout before, and wow It was bad.
I found my 0.125" calibration pin that came with some precise bits collets from an old router. 0.006" runout. And the pin only stuck out of the spindle half an inch.
I never would have guessed. I still had my collet-care and found some cu-tips I was able to clean a bunch of gunk out of the taper.
Now I'm getting between 0.0003 and 0.0025 (best I can tell with a 0.001 dial indicator).
Im not sure if the remaining runout if from the spindle taper or from my collets. I got er20 collets from ebay seller halmia.
They were $8 a piece and supposedly comforms to DIN 6499 standard. Not sure if there are any runout specs on that standard or if that just means its er20.
I'd like to buy a couple collets with specified runout to check against. Also would like to get a longer gauge pin to know what the runout is an inch lower than I'm checking now.

[alan_3301]

Today I was trying to check how square the x and y axes are.
What I ended up with was a 12x24 carpenters square clamped to the table, and probing the sides to see how far out it was.
With clamps and stuff in the way, i probed 10 inches apart on the 2 sides of the square. I came up with a 90.008469 degree angle.
If my machine travel is a parallelogram of 50 inches, then it will be off by 0.00147" at the limits of travel. Sounds right?

(20in diameter * pi) / 360 = 0.1745 inches per degree
0.1745" * 0.008469 degreees = 0.00147"

Now this is assuming the cheapo square I am using is exactly 90 degrees, and my probe runout is exactly 0.
Maybe I will get a quality one and check again some day.

If thats right, then I wont bother with another Y home switch to square the gantry.
Right now I am pulling it against the endstops, then turning on stepper power.
Now if only I could get my bits to spin with less than 0.001 runout, I'll be happy.

[LouF]

Alan,Why don't you cut some squares a couple different sizes and then take your measurements from the squares I would think you could tell if your off and which axis.


Lou

[alan_3301]

Alan,Why don't you cut some squares a couple different sizes and then take your measurements from the squares I would think you could tell if your off and which axis.


Lou

I think that will work if I use an external measuring device. A tape measure and 6" calipers is all I have.
I don't trust my tape measurements for being very accurate. I did measure a 4" wood square I cut out. 4.004" x 3.997"
with corner to corner measuring 5.644" x 5.641". This gives me a 90.0305 degree angle.


Now that I look back at my math, I think i forgot something. The machine will be off by 0.00147"X per 10"Y so at 50" my X will be off by 0.0147".
That sounds more reasonable.

[alan_3301]

I am working on a cnc lathe that I am cutting out with my crp4848, and wanted to share some aluminum cutting success.
I am cutting out 30mm aluminum plate. In the past I had been using onsrud 65-025 single flute bit, but was having problems with the tip chipping and at $45 a pop, I was looking for cheaper options.

I ended up using this ebay bit, 1/4 diameter 1 1/4 flute length 2 flutes. 1 4" Carbide Router Bit 2 Flute Spiral Upcut | eBay

My magic settings were 15000rpm 30ipm @ 0.070 DOC. comes out to exactly 0.001 IPT.

It cut beautifully, though I did have to air blast the chips out after every pass. It took 17 passes. A little slow, but I will not be cutting metal that thick very often.

One thing that was suprising, and I'm sure it was a fluke, all the dimensions of my parts the I can measure with a 4" micrometer came out to within 0.0001
I'm not sure about the larger parts, but with a 12" digital caliper they are all within 0.001"
I'm pretty impressed.

Here is a link to the lathe build.
http://www.cnczone.com/forums/vertic...cnc-lathe.html

[alan_3301]

I finally remembered to take a picture of something I made, I haven't made much in the past year, hopefully one day I will be unemployed, and that will change!
It is a standing desk converter, just an extension to make it comfortable when standing at a desk.
Now I just need to remember to use a better camera when taking pics.
Attachment 250476

Attachment 250478

Attachment 250480

Attachment 250482

[LouF]

Alan, nice job I like it what kind of lumber did you use?

[alan_3301]

Thanks, It is MDF.
I had planned on plywood, but didnt have any and didn't feel like going to the store.
I was a little concerned because MDF usually has a poor looking edge after cutting out, it looked ok though.
I wanted it to leak really nice, so I used a roundover bit with the bearing on it, lowered the router to the correct depth, and finished all the edges by hand, with the router stationary.
I worked out really well, and I will do this in the future.
I don't know why I hadn't tried this before, for some reason I though i needed a manual router table, but this works great.

[LouF]

The MDF looks good.

[alan_3301]

Finally got around to cutting some steel on this thing. This is a 12-1 tooth trigger wheel for a motorcycle fuel injection system.

Material is 1/8" A36 Hot rolled steel sheet.
Cutting bit is a 1/8" 2 flute TiAlN coated carbide
Cut settings for a very conservative 0.0003" per tooth chipload, but the end mill didn't seem to mind, and the part had a good finish.
12000 rpms
0.008" Depth of cut
8 ipm

Probably lots of room for optimization, but I don't think I will be cutting steel very often.

[dgage]

Nice! Steel? What machine(machine,spindle,base) do you have?

[alan_3301]

Thanks, It's the machine in this build thread. An original version of the cncrouterparts 4848 machine, with a chinese 2.2kw spindle

[dgage]

Wow. Nice. Thanks for sharing. Was that a dry cut or did you spray any lubricant?