Diary of a FoamCutter building a jgro router table

[Glidergider]

Guys,
Thank's for the tips about flattening the point. I'll try it today. Also, I'm going to build the remaining 5 skates today as well.

EDO: I enjoyed soldering my foam cutting HobbyCNC driver too. Its amazing how satisfying it was to solder, test and and assemble it. I might go that way again. Good to know that the 200 in-oz steppers are powerful enough. How about your jog speeds and cutting speeds. How fast can you cut?
Dave

[edo]

I thought I was getting pretty fast jogs, but then realized that any feedrate setting above F80 really didn't have an affect. Manually timing the moves tells me I'm jogging at about 78ipm.

I've been cutting MDF and HDPE at 30ipm and limiting the cutting depth to less than 0.20". This just 'looks' like a good speed and I haven't really pushed it until I was missing steps. I'm afraid of breaking the bit or something. When you're manually pushing a router through wood you can 'feel' the right rate, with the CNC, I just don't have anything to compare it too.

Here's a pic of my X&Z axis. I'm using a HF Trim Router with a Whiteside 1/8" spiral upcut bit that only cuts to a depth of 1/2". These bits are $25 a piece so I'm not really inclined to push the machine until one breaks. The Trim Router has a 1/4" collet so I haven't been able to try the more common 1/8" spiral bits that are cheap enough to be disposable.

What do people use to cut 3/4" material? I'd hate to go to 1/2" or larger diameter bits just to get one that's 3/4" long and fits a 1/4" collet - seems like I'd be wasting too much material.

[tajord]

EDO: I enjoyed soldering my foam cutting HobbyCNC driver too. Its amazing how satisfying it was to solder, test and and assemble it. I might go that way again. Good to know that the 200 in-oz steppers are powerful enough. How about your jog speeds and cutting speeds. How fast can you cut? 
Dave

Seems if you're watching the dollar and still looking for a good board, HobbyCNC's the way to go, not that i'm putting down Xylotex in any way cuz they are some out there that has had good results, but they are some that have had some troubles and in the end prefered the HobbyCNC to the Xylotex
check out this thread

Note: Big thread.

http://www.cnczone.com/forums/showthread.php?t=26792

[HayTay]

Originally Posted by edo What do people use to cut 3/4" material? I'd hate to go to 1/2" or larger diameter bits just to get one that's 3/4" long and fits a 1/4" collet - seems like I'd be wasting too much material.

edo,

Enco has Atrax brand, 1/4" solid carbide, 2 flute, end mills with various LOCs from 1/2" to 1 1/2". They're probably not the highest quality but they work for what I'm cutting. I think some other people here on the Zone are using them too. Maybe they can chime in with their 2 cents, also.

Link to Enco Carbide Single End Mills.

[edo]

HayTay - thanks for the link. Although they don't have 1/8" cutters for a 1/4" collet, I'll try some of the longer 1/4" Enco bits. They must be on sale! I added a few to the shopping cart and the price that shows is a lot less than what's listed on the catalog page; e.g., the 3/4" LOC one lists at $12.09 and is selling for $6.29. This is just the motivation I needed to put another Enco order together for some ACME rod I've been wanting for another project.

[Glidergider]

I remember seeing a modification to the slide rails that included a U-bolt, some clear plastic tubing and a third skate bearing. The third bearing captures the gas pipe completely. I'm trying to find that thread. Can anyone lead me back to it. And, whats the verdict, is it a good modification?

[edo]

You may have a problem with the Z-axis if the bolts are too long. Unlike the X & Y bolts that go all the way through and get nuts, the Z ones go into threaded holes and if they're too long, they'll hit the Z-Axis Lead Screw. I used 1/4" Pan head screws instead of hex bolts which I was able to get in the right length.

[HayTay]

Originally Posted by Glidergider Good link to the end mills. Here's my progress today. Pretty much finished the skates, all 6 of them. Couldn't find the 1-1/4 inch long bolts, so I opted for the 1-1/2 inches. That shouldn't be a problem I hope.

I think you'll be OK. I just took a quick look and measurement on my JGRO table to make sure. It looks like there is enough clearance for the 1 1/2" long bolts on all three axes. If there is a problem you could always cut them off using a hacksaw or a cutoff disk in a Dremel or RotoZip.

edo & Glidergider, glad I could help out on the end mills. Enco does have other end mills, ball end mills, etc. Just do a search and you may come up with some 1/8" end mills with a 1/4" shank.

[Glidergider]

HayTay,
I don't know how to ask this question, but here goes. I'm trying to understand the Bit/Chuck relationship of a router. My router only takes a single diameter shank/bit. Is there an adapter which can be attached to the router to get an adjustable diameter chuck? Are there routers out there with an adjustable chuck as standard equipment?
Dave

[HayTay]

Glidergider,

Good job on the bearing trucks. After scrutinizing your finished truck picture a little more it looks like you need to add another nut between all of your bearings and the aluminum angle on the 8" ones (long axis, CNC_assy08) that ride on the 1" gas pipe (CNC_dtl03). The plans call for a 0.520" spacer (CNC_dtl26) which is a PITA to find. Two 5/16"-18 hex nuts are almost exactly 0.520" and are cheaper and easier to use. If you feel the need to be exact, you can measure different combinations of hex nuts to find pairs that are 0.520" +/- 0.003. It's really not super critical, though. See pictures for clarification.

I also found a picture of the GANTRY - CORNER BLOCK (CNC_dtl21) from when I was putting together my gantry. Hopefully it will clarify its purpose as discussed in one of your earlier posts.

[HayTay]

Originally Posted by Glidergider HayTay, I don't know how to ask this question, but here goes. I'm trying to understand the Bit/Chuck relationship of a router. My router only takes a single diameter shank/bit. Is there an adapter which can be attached to the router to get an adjustable diameter chuck? Are there routers out there with an adjustable chuck as standard equipment? Dave

What your looking for or needing are 'collet adapters', 'adapter bushings', 'collet reducers', or some other combination of those words.

You can purchase them from MLCS Woodworking, Lee Valley Tools, and other places. Those two links should be enough to get you started on the right track.

[MARKG]

Originally Posted by mcyr Dave, Great question. I've only given it a little thought and all I can come up with is about the same as you suggest: Route the top and bottom separately with a lip around the edges. The lip could be used for alignment before gluing, then cut off??? I guess since the two would be mated together it might be a good time to put some spar material in. This might be good for DLG wings if it doesn't add too much weight. Do you think the material would become too thin routing this way that it wouldn't be feasible? Might be a particular problem with Drela et al foils. Another option would be to use a 4-axis machine so that you route both sides (not a perfect solution either I realize). Biggest drawback of this is I haven't got a clue how you'd keep the piece stationary enough. Mike

Hi guys, did you see the full how-to on how the Encore HLG wings are done in RC Soaring Digest. So simple it's frightening! The key is vacuum. Even the balsa tails are done ..both sides, very cool, very accurate.
Have a look here, page 32 in the pdf file.:

http://www.rcsoaringdigest.com/pdfs/...SD-2006-09.pdf

Keep up the good work Mike!!

Mark
Montreal
www.matsclub.org