The MiniMe Project

[Madclicker]

My big 1/3 sheet router is so successful that I wanted to continue some of the best of that design and combine it with improvements I have discovered since I started that project.

In the near future I will build a full sheet machine(maybe call it MaxiMe), but I don't have the room for it right now.....so, I'm designing and building a smaller machine. I owe everyone on the zone that posted any unique ideas a debt, but I think Spalm (Steve) had the biggest influence on the direction I took with this machine. He and Benny were the first to use V bearings that I know of. Also, Steve is the only one I know of that attempted to make an improved DIY drive that wasn't just based on canned data sheet schematics. Blazing new ground is commendable.

I expect this little machine to be very fast and accurate. At first I will test it with my Gecko drive cabinet, but in the end the drives will be my own design.

I spent a couple hours modeling the base. I can see now why there are so many newbees with drawings and no results! It's kinda fun to draw this stuff, but work sucks!

[spalm]

The trouble with blazing is the increased probability of getting burned.

Not sure if you are looking for comments on this design, but I have a few:

I like the open frame you have drawn so that the gantry can have a support across the bottom. It will make the gantry much more resistant to racking. I wish I had done this. However, it looks too feeble and might have the tendency to parallelogram when the machine gets a rocking. Maybe add some internal triangle supports to the ends.

It also looks like the bed does not have enough support to keep it flat. Maybe add a thin torsion box underneath it for support.

Also, why the bolts holding the wood together? Use dowels/biscuits and glue. Furthermore I have some concern with the rail bolts pulling out or coming loose. Maybe some kind of captured nut, threaded insert or even threaded rod running all the way through to the other side. You are probably going to have to adjust these rails for parallelism and possibly shim them for width adjustment.

I am still a big proponent of dual screws. Want to work out something new? Nobody that I can recall has gone with a single screw and cables/pulleys to keep the gantry riding square. This would be a lot cheaper than a second screw. Maybe just consider it so it could be added later.

Steve

[Madclicker]

Thanks for the input.

Originally Posted by spalm I like the open frame you have drawn so that the gantry can have a support across the bottom. It will make the gantry much more resistant to racking. I wish I had done this. However, it looks too feeble and might have the tendency to parallelogram when the machine gets a rocking. Maybe add some internal triangle supports to the ends.

I hadn't planned on attaching the gantry to the bottom. I intended this to just complete the "box" of the bed and allow the machine to sit on saw horses. Did you have a big problem with racking using the v-bearings?

Or, are you talking about tying the gantry together at the bottom? Now, I recall that you didn't on your last.

Originally Posted by spalm It also looks like the bed does not have enough support to keep it flat. Maybe add a thin torsion box underneath it for support.

I thought long about whether to make the bed a torsion box or not. I have a 4' router table made much the same way and attached to my table saw. The only other support is a jack stand at the end. In 4 years it has sagged 1/16". My reasoning for this design being good enough to not sag appreciably is that there are the 2 angle rails solidly bolted the full length. Also, the 5 t-tracks extrusions will be screwed and epoxied. Finally, the top and bottom will get phenolic laminate. This creates a psuedo tosion box. I think you laminated the uprights on one of your builds and noticed the improvement in stiffness.

Originally Posted by spalm Also, why the bolts holding the wood together? Use dowels/biscuits and glue. Furthermore I have some concern with the rail bolts pulling out or coming loose. Maybe some kind of captured nut, threaded insert or even threaded rod running all the way through to the other side. You are probably going to have to adjust these rails for parallelism and possibly shim them for width adjustment.

The bolted design is for easy breakdown/assembly. Every place I have bolts there will be hardwood bisquited into the MDF with t-nuts for the threads. The bolts also allow the adjustments you mentioned.

Originally Posted by spalm I am still a big proponent of dual screws. Want to work out something new? Nobody that I can recall has gone with a single screw and cables/pulleys to keep the gantry riding square. This would be a lot cheaper than a second screw. Maybe just consider it so it could be added later.

I kept the cable/pulley option open on my first machine. Never had a problem with racking that couldn't be solved by "aping" the sides together.

I've decided to decrease the overall height of the bed to 7". This will give just enough clearance for a 3" lower gantry torsion box.

[Madclicker]

Well, bought the motors for this. PacSci 34's and I can't find the data sheet for them. Oh well, time will tell if I did good. I think they will be 600+ oz/in based on the current/voltage specs on the label. Need to change my drawing to the pretty red colored motor...but, I did change the design height to 7". Hopefully I can squeeze everything I need to in the 4" hole. Pic 1

I have started cutting stuff for the base, but never enough hours in the day. After I get the top glued up I'll cut the t-track grooves on the original machine.

The motors I'm gonna use are almost 6A, so I definitely need more than hobby drives for this project also. This time around I'll design my own. I have some goals for this design:

1. 10A bipolar (probably less)
2. 70V (definite)
3. PIC based controller
4. Feedback compensated for resonance issues (very important)

This one will be more fun than the last because of the educational part. The last was just work to get a machine working.

[Madclicker]

Got my motors today. Nice looking. Still can't find the data sheet.

[Rance]

Originally Posted by Madclicker ...Never had a problem with racking that couldn't be solved by "aping" the sides together...

OK Steve, I'll bite on this one. What is 'aping'. I'm a woodworker, should I know this already? Thanks.

[Madclicker]

Originally Posted by Rance OK Steve, I'll bite on this one. What is 'aping'. I'm a woodworker, should I know this already? Thanks.

LOL.

aping: To pull on wrenches like an ape.

I think I picked this term up when I read about how some people ruined the collets on routers by "aping" on the wrenches.

I don't think I'll be able to use that technique with this machine, though. The v bearings ride differently than the skate bearings on pipe.

[acondit]

Originally Posted by Madclicker Got my motors today. Nice looking. Still can't find the data sheet.

Steve,

I have a PacSci Stepper selection pdf (1.7mb) that lists the specs for E series (Sigmax Hybrid) steppers. If you post the model number, I will post the specs for that model. If you pm me with your e-mail address, I will send you a copy of the pdf, since it is to large to attach here.

Alan

[Madclicker]

Originally Posted by acondit Steve, I have a PacSci Stepper selection pdf (1.7mb) that lists the specs for E series (Sigmax Hybrid) steppers. If you post the model number, I will post the specs for that model. If you pm me with your e-mail address, I will send you a copy of the pdf, since it is to large to attach here. Alan

Thanks, any help is appreciated.

Model: 802D3437-28774

I got a pretty good deal on these @ 3 delivered for $50. The guy has a bunch more. When I confirm they will work others may be interested.

Will PM my email. Thanks.

[Madclicker]

Thanks for the data sheet Alan.

Looks like my original guess was right. These motors are somewhere between 627 and 679 oz/in.

I think these were a killer deal at less than $17 EA DELIVERED!

[jmytyk]

um yes, please send the info for where to get 'em... thanks.

[Madclicker]

Originally Posted by jmytyk um yes, please send the info for where to get 'em... thanks.

I got them from an individual. I'm trying to work out a deal for a quantity now.