Second router finished - 8020 Bearings

[Hack]

I have finished my second router. Its cheap yet a big improvement over my first one. Much more rigid and accurate. Used 8020 and thier bearings, 1/2-13 threaded rod, delrin nuts. Have the dust collection finished as well, but still need to take pics.

Rapids are conservatively at 35 ipm - cutting mdf at 25 IPM (.125 D.O.C) very well. 24 x 36 cut area.

Some pics below

[CNCRob]

It looks great Hack

[lovebugjunkie]

Very nice router you have Hack.

I have been living on the 8020 and Faztek web sites for the last two months putting together different ideas, but was always put off, as I did not think their bearings would work on a Router as you have done. Since yours turned out so nice, it looks like it will be a go for me to put in an order for the parts.

Did you order all the parts pre-cut? If not what did you use to cut the lenghts you required?


If you don’t mind would you post the dimensions of the 8020 you used?

[Hack]

No I cut all of the extrusions myself using a miter saw and an 80 tooth carbide blade. Cuts nice. Then I tapped the ends where I needed. All extrusions a 1530

A word about the 8020 setup - If you are looking for very high degree of accuracy do not use this system. For normal wood router, i feel this system is more than sufficiently accurate. I am a cabinetmaker by trade, and am used to doing close tolerance work, and this is quite accurate for those purposes. One of these days I am gonna get a little more gutsy and try some cuts in aluminum. I feel this may be stiff enough to get by with the right bits, speeds and feeds. Not sure though.

I have also noticed a little extra drag using these bearings compared to roller bearings, so you may wan to condiser slightly larger motors to compensate. I am using 276 oz with xylotex board, 24v power supply and 1/4 microstepping.

If you have any moer questins, please feel free to ask.

Dan

[Hack]

Be sure to check out 8020 on ebay as they have a store there and if your patient you can easily save 25-40% on the extrusions and bearings.

[carlnpa]

Thats a good basic design, nicely done. It would scale up readily to a larger machine. Thank you for the ideas.

[Hack]

Thats the nice thing about the extrusions......just order them how ever long you want. Also the 1530 are situated so that they can span quite a distance without sagging.

I recommend checking out 8020's defelction calculator (free) before enlarging to much.

One thing that I do like about this design is the stiffness of the z axis. I think one could build this a get quite a bit of Z clearance to do some good 3D work if they wanted.

[Evodyne]

Hack,

I love your machine! I bought two 10' lengths of the 1515, each with one bearing. Got it off the 8020 surplus store on eBay at a reasonable price. If I grab a single bearing and torque it hard by hand, I can just detect the slightest movement.

A lot of people have asked if these bearings are suitable for use in a machine: the usual answer is "NO" because of the looser fit.

BUT if a wider piece of extrusion were used (like your Y axis) AND multiple slides were used (again, like you've done) this should mostly go away. I suppose a clever person might even find a way to spring load one slide against another to "preload" the assembly, much like is done with double nuts on ball or lead screw assemblies.

Your machine can go a long way towards dispelling the notion that the 80-20 bearings aren't suitable for a CNC machine. Can you give us any idea of the accuracy you get when cutting your MDF pieces? I suppose other machines that are lightly loaded would be good candidates as well. Plasma, flame, and laser cutters come to mind. Foam cutting rigs too.

Oh, do you apply any extra lubrication to the delrin, or do you run it dry?

Evodyne

[Hack]

Yes I apply a little spray lube to the delrin nuts. I honestly dont know if it helps or not, but certainly doesn't hurt. I have also found that if you apply a dry lubricant to the bearings, it does help quite a bit.

As far as accuracy goes, I haven't really measured it really close. I just know that when I cut a peice at 30", it comes out 30". The machine is more accurate than my tape measure. I'm sure that if I got out the calipers, I might find some varience, but this is woodworking. I have cut quite a few holes in melamine that needed to line up with the bearings, etc and they all work. Up to 16 holes per peice, no alignment issues.

The material itself will move more than the router will be off. I think that is one of the biggest concepts that people need to remember. Wood and wood products will have a tendency to expand and contract quite a bit, so how exact does a machine have to be?

Again, for example, if I cut a 30" piece, it seems to come out 30"

[smarbaga]

hello.
how much would a machine like this cost to build,
including motors, electronics , the works ??
not counting time , thank you

[Hack]

All new materials, less than 1300.00

I built mine for about 975.

That includes motors, controller, everything except trim router and computer. Already had them. I was able to find some decent deals on 8020's ebay store for the extrusions, but everthing else is new.

I don't know if this is the proper place to mention this, but i am planning on selling plans for this router soon. Probably within 2-3 days they will be ready. Just double checking them and making sure all part number etc are correct. I will also be offering all the melamine pre-cut and drilled except for the table top itself. It is just a straight cut and would be to big to ship with the other parts. If you order all of the extrusions machined from 8020, all a person would have to do is fab the delrin nuts, bolt it all together and wire it. Again, for the price, I think it is a very easy router to build, and could really be built in stages if someone doesn't have all the money at once.

[smarbaga]

thank you very much for sharing the cost with myself ( and others, i am sure )
a great idea to sell plans and a precut kit,
best of luck in your venture