Thanks for the inspiration, GliderGider!
Hello All-
First, I'm a newbie who has been visiting this site for the last few weeks. I have always been interested in CNC and when I saw the plans for the JGRO, I knew I HAD to build one of these.
I do a lot of woodworking, so building the projects has been fun and rewarding. Unfortunately, my wife has the digital camera on vacation with her, so I have no pictures to show.
Anyways, I thought it would be fun to make model airplane parts, and after seeing the pictures the GliderGider posted of his balsa ribs and jigs, it pumped me up even more to finish this project.
I never even though about using the CNC machine to make jigs (like he did for the spar hold-downs). I love making jigs, but they take so much time (such as home-made edge banding clamps). I built one and it took me almost 2 days, and I need like 30 of them! Well, once I finish my JGRO, I'll use it to make jigs!
Thanks for the inspiration, all of you. I love this news group! It's like sitting in a room full of geniuses sharing their ideas and pictures! I'm trying to absorb as much as I can.
Brad
Coding for balsa parts
Glider-
Been lurking on your thread for a while now and was wondering when you were finally going to use your machine to cut planes/gliders. Are you using the 1/32" diamond downcut bit that quicker used to use? ( http://www.drilltechnology.com/router/downcut.html ) Are you leaving tabs on your parts to hold them in the sheet until you are ready for them? And what software are you using for these cuts? Thanks for all the great info you have provided.
-Mega
Brad and Mega,
Thanks for the kudos. I constantly amaze myself how much fun this machine is. My only regret is not making a giant CNCI have loads of fun and just as Brad said, it dawns on me slowly, that hey, I can build tools. I can machine the spars in a double taper. I can cut that myself.
I did buy my .032 bits from drilltechnology. They are so small, its hard to see the teeth. For the life of me, I don't remember if I bought up-cut or down-cut. I'll report later on that subject. I'll review the package label. I'm guessing down-cut because the edges were very clean.
TABS: On my first rib cuts, no I didn't use tabs. No ill effects by not having them either. I might use tabs in the future though.
Software: I'm using Compufoil for the airfoil stuff. TurboCad if I have to draw or modify a drawing. VcarvePro for the g-code generation and Mach3 to put the bit to the wood.
hi
Glider very nice work indee
cheers
I just examined the container for the bits. They are downcut bits.
Nice work!
Hi Gliderguider. Nice work on the ribs. And I like the jigs you've made with the HDPE to hold down the spars. What kind of bit did you use to cut the HDPE and where did you get it? What depth of cut and feed rate are you using? Do you know what your router speed is (rpm's)? From what I've read about bit selection for the material to be cut, did you use a single edge "O" flute?
Lots of questions. Sorry. I am so close to finishing my table I can't stand it. I've been using a smaller cnc router (Dremel spindle, 1/8" bits) my dad built (and graciously let me use) to make parts for my larger table. I'm about ready to make some bearing plates from HDPE (5/8" thick) and would like to cut them on the smaller table.
In the mean time, I've bought some software and actually learned enough to try a 3D cut. Went for broke and tried the highly undercambered E214 airfoil. Pretty rough as seen in the attached pictures, but that's due to inexperience and a limited number of bits on hand (1). Proved the concept tho so I can't wait until I can try this on a DLG wing.
Best regards,
Mike
Mike,
Good work on your test cuts. Looks great. I remember the feeling of getting close to finishing my CNC. Enjoy the rush.
There's really no magic in bits from my prospective. For RC model frames in 1/4 ply, I use a .125 2 flute bit. Up-cut, but I also like the side cut. I wish I had a downcut.
I don't have a .0625 dia bit yet. That might me superior. For the balsa sheets, I have and use the .032 dia down-cut. The link is above.
For all the plaques I use a .25 bit. I use upcuts, and sidecuts and the sidecuts are probably give the crisper edge.
I made my bearing plates from MDF and I think its just as good as the plastic. For the pipe alignment plates, the plastic is a must.
So far all my cutting experience is with 2.5 D items. I haven't done a 3D project yet. Its just a matter of priorities. I'll get there someday.
I don't know what a "O" flute is. Maybe you can ejumakacate me.
Congrats on getting your first 3D airfoil cut.
quick question, since I know you did it.
What Size wood screws did you use? I know to predrill and all, I was just wondering
#8 1.5 inch and 2.0 inch.
#6 1.25 inch
I probably used some 2.5 inch when mounting the bottom end plates to the base structure. That's a double thick MDF so its a long connection.
Tonight I cut some more ribs. I needed to redesign the wing because of a joiner issue. So I cut both wing halves out of a single 4 X 6 X 24 inch sheet of balsa.
Here's the subassembly of the wing ribs. I did a little sanding but very minimal. I used Compufoil to design the ribs. I love that program.
This wing has a 7 inch root and tapers to 5 inches at the tips. The span is 34 inches.
Here's a link to the little bitty bits I used tonight.
http://www.drilltechnology.com/router/downcut.html
On the label, you will see the partnumber is DCD-.0312F. The first DC means Down-Cut.
Tonight I started gluing spars together. Cut, placed and glued the shear webs into place. I also cut the wing joiner position. I used the brass tube as the cutter. So far so good. Just one wing tonight.
The computer image is from the program Compufoil. Check it out at www.compufoil.com/index.shtml and tell Eric I sent you. Its a nice program and it outputs a DXF file designed for CNC machines.
Last edited by Glidergider; 07-14-2007 at 08:44 AM. Reason: Corrected Compufoil address
Small spelling error in address
I noticed that the "p" was left out of Compufoil.com just in case anyone tries and wonders why they can't connect.Originally Posted by Glidergider
I used to do a lot of scratch building and a CNC machine would have been nice. Back then I don't even think there was such a term as "CNC" as you would have needed a whole warehouse just for the computer to run it. Ain't progress nice! Well maybe sometimes.
Seeing your posts and pictures makes me want to get started again.
Cheers
Don
Don,
Good catch. I fixed the web address spelling mistake.
Below is a low angle picture showing the fuzzies from the CNC cuts. This is using the down-cut bits.
I built a new vacuum box (low pressure) to hold my future balsa ribs during the routing process. The size will accept an 8 x 36 inch sheet of balsa. I have to check the flatness of the cutting surface which I know already is off by about .020 at least. The perf board may just get shaved to achieve the flatness.
Good thread.
Are you using your DC to power the table?
Steve
DO SOMETHING, EVEN IF IT'S WRONG!
Steve,
Yup, I power the vac table with the dust collector. I have a splitter on the DC. When cutting balsa, I let the dust fly and divert all the vacuum to the suction table.
I'm still around and I'm still cutting wood. This summer I took some vacation and an other distractions consumed me. Yet, I'm still have a great time with the CNC machine. Here are some pictures of the work done since I've last reported into the zone.
I've cut some custom picture frames, and I've started experimenting with some ice tea coasters.
The puzzles are also photo frames.
I forgot to mention the blue feathered airplane pictured above. It is cut from Fan Fold Insulation. It's a well known foam design. I added the scalloped trailing edges for fun. This foam airplane is finished by adding an electric motor, battery, receiver, and 2 servos. The finished airplane is often used in combat, where two similarly sized airplanes a flown in close proximity, the pilots trying to knock the other airplane from the sky by mid-air impacts. Being foam, these airplanes often just bounce off each other and continue flying. It's actually pretty hard knocking another airplane from the sky.
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