Looking for CNC Mill Part I

[Gary Blaylock]

Hi Balsaman,

Your the person who got me to looking at these clocks. Your work is always really nice. I have a few questions about the clock posted. Does the pendulum
actually work or is it just for looks? The reason I ask is because the pendulum is hung from the top spacer peg and appears to be not connected to any parts. Also there is part #21 which is called a "yoke" that I can not find where it goes. I don't see it any where on the exploded plans except where it is drawn for a part.

Thanks for the help in the past and post some pics of projects you have built. It will really get the builders to working on their machines.

Gary

[balsaman]

Gary,

Your's is nicer with the quality plywood.. I threw mine in the garbage. The MDF doesn't hold up.

The pendulum is functional. The drawings are missing some details. The yoke goes thru the back piece via a dowel and is attached to the gadget the increments the funny shaped gear (sorry for the technical terms). The yoke cradles the shaft of the pendulum. As the pendulum swings is allows the gear to index once. The gear also keeps the pendulum swinging. The length of the pendulum determines the speed of the clock. Adjust the length to get it close to accurate. In the end I quit fiddling with it cause a windup only lasts 8 hours or so, so who cares if it's accurate.

Eric

[Gary Blaylock]

Hi Eric,

Thanks for the info. I thought the escapement should be attached to the pendelum some how, now I see. I plan to stain and seal each gear a different color as this is just a show piece. Maybe it will run a few minutes at a time as I show it off to friends. So far I have cut the dxf files and all parts fit right in place.

Thanks,
Gary

[Mick Molloy]

Where did you download the cad plans from, I only saw the pdf version on the clock webpage...

Has anybody built this machine.....

[OzDragonFlyer]

Mick, my first small one was made similiar (they all basically look the same when you think about it!) Dual leadscrews on the Y axis though.

All aluminium, I used commercial linear bearings running on 20mm hardened shafts, zero backlash acme screws and 200oz steppers. Great little machine but the rails did flex a bit when taking 1/4" deep cuts out of ply/mdf.

I recently built a nice new base & spoilboard for it using my large cncrouter, put it all back together and haven't used it once since :)

[Mick Molloy]

You want to cut the mdf for mine ;)

Yours looks very good any demo's of the work done..

[Gary Blaylock]

Hi Mick,

Just e-mail Brian for the plans. He will send you a link where the dxf downloads are. They are free and he only asks you to click on his sponsors link.

Gary

[OzDragonFlyer]

mick: when you decide what you need send me a dwg and i'll cut 'em out.

i used this little table to make some of the aluminium parts for my big table..Natural progression! :)

[Mick Molloy]

mick: when you decide what you need send me a dwg and i'll cut 'em out.

i used this little table to make some of the aluminium parts for my big table..Natural progression! :)
WOW that would be great, where in Sydney are you from, I lived there for 28 years before moving up here to Brissy..

[RCEE BUILDER]

Ozdragonflyer, please let me know what type of drill bit (or whatever you call it) do you use on your high speed router ?

Murat

[OzDragonFlyer]

can't really go wrong by having an assortment of 2 & 3 flute ball/endmills and upcut router bits, sizes from .3mm up to 6.25mm.

I have a few high helix aluminium mills and also an assortment of V engraving bits. I don't really do a lot of thru hole drilling (mainly pilot holes) but ballmills work pretty well when theres more than I care to do by hand.

All carbide, they last much longer if treated right.

[Mick Molloy]

what format does your cnc router need OZ cad drawing G code (what ever that is etc) I would like to try to convert the drawings myself if i can.... i have them in autocad DXF file.

[topflight-rcu]

OzDragonFlyer, I have the plans for the same CNC machine and have located some stepper motors but I am unsure if the work. They are Superior Electric SLO-SYN Step Motors Model number SM-200-0030-HZ and it also has on it 3.3 ohm/PH, 4.0VDC and 1.2 A/PH. I am assuming that "PH" stands for phase, right? I found them for 7.00 and couldnt pass it up. Will these work for this CNC?

Thanks Joe

[xairflyer]

Those steppers will work well, ideal for a small CNC

[topflight-rcu]

xairflyer, Xhanks for the response. When you say small, how small, at least 18 by 24? What controller would you recommmend and any other info on the rest of the hardware would be great.

[topflight-rcu]

xairflyer, Would it be good for a mahine that was posted by Mick Molloy on the previous page?

[OzDragonFlyer]

Topflight, as Xair stated, they will work quite well, I guess they will be rated around the 120-150oz/in mark if they are relatively new. You should be able to get decent performance out of them with a chopper drive at 24-30V. Many to choose from these days (but geckos still seem to get the best torque/speed from steppers)

Depending on the weight/friction of your individual axis' 24-30" would be a good starter for direct drive (you could go bigger on the Y axis if you used a dual screw/motor arrangement)

[topflight-rcu]

OzDragonFlyer, I am new at the CNC stuff so these questions might seem kinda dumb. First, what is a chopper drive, Second, what is "Geckos"? and last , what would be a good controller or interface to control these stepper motor on the CNC machine? Thanks for all the reply's, this seem like a very interesting project. I plan on using the CNC machine to cut out Foamies, 6mm and 3mm thick.

Joe

[xairflyer]

Those motors will be perfect for the machine Mick posted, drivers will depend on your budget.

All you need is a driver board either one for each stepper or a board that contains all three.
To supply the power you can modify a ATX computor power supply or build/purchase a higher voltage one.

Regarding the drivers
You can buy the excellent little K179 driver board from www.kitsrus.com available from one of their resellers for about $9.50 each (need three).

Or you could buy The HobbyCNC board which is also very good and well priced.

[Tree_Magnet]

cnc2play if you are still looking for channel i found a place in brampton cost me 10 buck for all i needed

Tom

[Dongledell]

What sort of amps do these set-ups pull? you mention the ATX computer power supply - not sure what they are capable of providing but I have a 0-36v power supply coming soon, but it's only capable of about 6 amps - is that enough?

[cnc2play]

Tree Magnet,

yes, i'm still looking for channel ... what is the address please ?

[xairflyer]

The amp output depends on the rating of the power supply. I am using a 400W computor power supply and I have 15A @ 12v.

With a 6A supply I would'nt run much more than three 1.5A steppers.

The extra voltage will give you more speed OK, I am thinking about building a 24v PSU but would like about 10A min.

[longhair]

Has anyone used the Xylotex board on their mill?

[Andy W]

Keep the ranting, accustation and personal attacks out of these forums. I've cleaned up and restored this thread. In future, please use the "report post to moderator" button (http://static.rcgroups.com/forums/images/buttons/report.gif) if this kind of thing crops up again.
..a

[OzDragonFlyer]

Topflight: Chopper drives are far superior to the lower cost boards which use resistors to limit the current flowing to the motor. The boards and the drives also run much cooler as their efficiency is higher. You can easily distinguish between the 2 by looking for large (>5W) power resistors. If the board has these, it's probably a current limiting type design.

Geckos are popular chopper drives. (www.geckodrive.com). A lot of high end users prefer these because they are able to drive the motors with voltages up to 80V (giving more speed). They are both rugged and reliable, and give great performance.

Longhair: Xylotex boards are a good low cost alternative for a basic setup. I found them to be quite fragile electrically and sensitive to noise without modification, but lots of people have used them straight up with no problems. You will need a parallel breakout board or a parallel port card that supplies the pins with a high of >3.3V for them to work reliably.

Power supplies.. Lots of people have used PC (ATX) psu's with their steppers with great successs. However, switched mode supplies have a limited bandwidth and sometimes struggle with the constantly varying loads placed on them. There are ways of modifying these supplies (big caps and load resistors) to get them to work better. Given that most pc supplies are only rated for 12V limits them severely though.

Often it's just as inexpensive to build a dedicated (higher voltage) supply using discreet components. The geckodrive website has white papers on this and many other subjects, well worth spending time reading!

[longhair]

Oz..thanks for the info.

I have a Xylotex sitting on the bench right now and have been following the Xylotex users group on Yahoo, but thought I'd ask the question here. It is supposed to run the Biploar motors I bought so that's why I got it. I also saw somewhere that 24v @ 6 amps is what I should use as a PS for it. So now I need to build or buy one of those....My hobbies are going to get me in trouble with my wife one of these days.

If anyone else has any input on Xylotex please let me know.

[Steve McBride]

Time for a part II - 2427 posts in a thread is about 2000 too many. Let's try and keep the new thread civil please?

http://www.rcgroups.com/forums/showthread.php?t=333499

Steve