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It's been a while but I've not been idle. More pics/info later, well, once I stop playing :)
Attachment 4022
Many thanks to all here for inspiration, to Arc Euro, RDG Tools, Chronos, eBay and a special thanks to Gary at Zapp for making a delivery during the 3 day week at the end of April :tup:
Edit:
Could a passing Mod please correct the the spelling of Sieg in the thread title?
Few more pics:
I started with the X axis, the screw is held by 2 skate bearings with pockets both sides. The inner bearing pocket, under the table of course, is full depth which left me with a lot of 'spare' to cover on the existing screw rod - hence the excessive number of washers :redface:. My first ever bearing pockets and my first ever play with a boring head/bar The motor plate is made from 3mm sheet cut from a standard 2U type rack mount front panel. Could do with a couple of mm off the length of the rods!
There is a little sprig of metal left on the cut out for the motor. I left it there ar a reminder that it take it more than a couple of bearings and a bolt to make a rotary table - whoops, as by largest cutter is 12mm and the required hole is 38mm it seemed like a good idea at the time!
Attachment 4032
Next up was the Z. Just a couple of thrust bearings, top one in a 1mm pocket. I chose to skip the skimming of the aluminium bar, probably not the right thing to do but it worked out ok. The shims, 3x coke can, were not needed to fit, but adding them gave a better balance wrt the head binding at full top and full bottom. This may be a useful thing to try on the stock machine.
I must say, hacking out the big recess for the column was great fun, the little X1 surprised me with its willingness.
Attachment 4033Attachment 4034
Thinking about bearings, I decided thrust bearings would be ok for the Y. Much the same construction as the X, but I don't know quite what I was thinking when I measured this out, I need to trim quite a big bit off those rods! I also need to find my needle files, those 4mm holes for the M4 screws are not quite right, The 38mm recess on the plate for the Nema23 motor mount is perfect :dance:
Attachment 4035
Drivers on hard board, lol
Attachment 4037
And a money shot, I'll try for a better one later
Attachment 4036
Part of the EMC2 - not designed for actual cutting - test logo, cut in 1 pass 0.25mm with a 3mm bit.
The edges are nice, but I did need to give a quick surface wipe with fine wet and dry.
Hard to see in the pic, but there is some chatter, I guess you call it, on the bottom of most cuts.
There's a circular mark at the entry/exit point of all cuts, is my head dipping?
The circle between the 2 and the 4 is almost perfect. All this was done without any gib adjustment from the manual setup and no backlash comp. applied. I'll work on that later.
So, a great fun project. I'd certainly recommend adding bearings to even a manual machine, once I snugged them up a little I removed something like 90% of the original backlash.
Also of note, I have not cut or drilled any of the original machine or parts - though this may change when I fit limit switches. It can all be put back to the original configuration with about 10 minutes work.
Of Limit switches: I worked for quite a while with a motorised Z axis, the saving in endless hand cranking was too good an opportunity to miss. This highlighted a major problem with gib locking, if you forget the lock is on you screw the drive screw right out of the coupling. I'm trying to come up with some sort of switch arrangement triggered when using the gib lock, for now I'll make do with a BIG sign.
I'll add some more pics if I ever get around to tidying things up.
Nice work! :)
Are you using the stock leadscrews and nuts?
How are you preloading the bearings?
Thanks
Heh, forgotten all about this thread until a moment ago when it popped up in google...
Thanks, but in truth it is a shoddy mess that no one would be proud of. Still, it got the job done and proves that even an inexperienced numpty like myself can make a fairly successful stab at building bearing and motor mounts.Quote:
Originally Posted by Memran
Sure am. Nothing on the machine was drilled, cut or harmed in any way. I highly recommend the fitting of bearings, even just thrust bearings to even the manual machine. They make for a much smoother experience and kill most of the backlash dead.Quote:
Originally Posted by Memran
Preloading: With the axis, bearings and block in place, wipe the machined part of the screw clean of oil and fit the axis part of the 3 piece coupling, setting it just a little snug. Wind a M6 nut on to the existing thread that's poking through the centre of the coupling piece. Tighten the nut until it feels just right, ie not too tight. Tighten down the coupling screw and remove the nut. Test for any play. Job done.Quote:
Originally Posted by Memran
N.B. The above is probably the 100% wrong way to do this but it worked and is still working.
While I'm here:
I fixed the sticky Z movement by taking some fine wet and dry wrapped around a flat surface to the worst of the machining marks on both the ways and the head - the back of the head was a mess and totally devoid of lubrication, here I started with a file - gently! - I also made a ham fisted attempt at adding a couple of oil ways :lol: to the rear. I added a little carriage to the bottom of the head but it was definitely the smoothing that had the largest impact. I'll repeat, the back of the head was a disgusting mess, before smoothing I needed one hand on the hand wheel and one on the column to wind the head up, after smoothing, even with everything tightened down, I could raise the head with little more than finger force.
The machine still suffers from head droop and for this I know of no cure short of replacing both the head and z column. After all this time I'm not sure if it's worth the effort.
Not that it really matters, but strictly speaking that's not quite true. Putting thrust bearings on the leadscrews reduces (ideally eliminates) screw end-float which is when the screw can move parallel to it's axis causing inaccurate positioning, even if there was zero backlash.Quote:
Originally Posted by ecat
If you want to be pedantic end float on the leadscrew is backlash according to the Oxford Dictionary:Quote:
Originally Posted by Jonathan
- 2 [mass noun] recoil arising between parts of a mechanism.
- degree of play between parts of a mechanism: typical gearbox backlash in these systems is 2°
Russell.
Hi Ecat
I've just found your post as I am getting ready to have a go at converting my Sieg SX2 from Arceurotrade.
Did you post any more pics after these - I'd love to see a bit more detail esp on Z axis.
Did you stay with this setup or move onto ballscrews, my plan is to use the original screws and see how things go.
Cheers
Ian
Hi Ian,
I've just this morning placed an order with Arceuro for an X2 mill for conversion having just sold one of my lathes to make some space in the workshop and pay for the mill. To keep the costs low I intend to start with the original leadscrews and replace the nuts with homemade anti-backlash acetal nuts. For the Z-axis I intend to do something similar to Hoss here.
Russell
Hi RussellQuote:
Originally Posted by russell
It will be good to compare notes then!
I guess you have actually ordered the SX2 cos I don't think they sell the X2 now? It makes a difference for the z axis as there is virtually no room on the head behind the motor to mount the screw. I guess this is where the cncfusion conversion comes in. I'm thinking of copying that design although I don't really like the force being on the side of the head. Having said that I have replaced the crappy spring support with a crude counterbalance (a couple of old brake discs on some steel rope!!) on the other side of the head. The counterbalance is an attempt to prevent the known 'nodding' of the z axis (I know about it now, managed not to read about it before I bought the thing)
The fitted screw nuts are steel (!) and have anti backlash adjustment on them, with lots of fiddling with gib strips etc I have about 0.05- 0.1mm backlash on the x and y at the moment. The acetal nuts sound interesting, how will you cut the thread?
Off outside now to start on version 1 of the x bracket.......
Cheers for now
Ian
I'd be wary of acetal. A much better solution is what I tried here:Quote:
Originally Posted by russell
http://www.youtube.com/watch?v=m6k8J...Gs_IoRUuanN2U=
Cheap, less backlash, durable. You'll probably want to use 4 bearings, like \/\/ for better rigidity and to cancel out the torque each bearing imposes on the screw.
Hi Ian,Quote:
Originally Posted by ian823478
If you join the Yahoo group http://groups.yahoo.com/group/hf47158toCNC_Moderated/ and look in the files section you will find drawings by Brian Pitts for anti-backlash nuts for the X1. something similar should be possible for the X2. Andy Birkett describes making them here. The alternatives are screwcutting on the lathe or......A clever way of making acetal nuts is shown here
Yes, fitting the z-axis leadscrew to the SuperX2 is a bit more difficult. I don't like the idea of counterweights and would like to fix the leadscrew as far forward as possible, preferably near the centre of gravity of the head to eliminate the rocking. Perhaps by moving the motor out to the side? I'll have to see how the belt drive is arranged when the machine arrives.
Russell