YET ANOTHER MDF ROUTER (UK BUILD)

[Gfowa]

After a fairly lengthy wait I have finally began my virginal post on this here special forum.....I say special because this was the only place to get so much info on one site, hence the need to lurk/lerk/lark around here for a year or so before I commit to a CNC router build.
In fact I began my search for components a long time ago hence the prices I am about to quote are reflective of the time I purchased them, for example the case hardened steel rod 20mm dia, 2x1300mm, 2x750mm, 2x300mm, plus 12x20mm ball bushings ( ok grab a hold of something) all for $118 to England from Singapore, no it is not a misprint $118 of which $30 was shipping, the same items now would be in excess of $300.
My machine is based upon many idea's gleaned from this website but not like any others at the same time. I have no CAD/CAM experience so I hope to rely on some of you guys for a little coaching in the field.
All of my dimensions are out of my head, no plans, I have built with regards to what materials I have/could obtain.
I know this is risky and yes I have encountered problems for which I have had to conjure solutions.
I will over the coming days attemp to post pictures of my progressive build

[Oldmanandhistoy]

Looking forward to the pictures

[Gfowa]

Ok here we go
It all started about june 2006 when I found this forum and was totally fascinated, So as you do you start to fish around for bargains, ebay etc, but in end most of my parts were sourced from the internet. Also I must give the guy/company a plug because he was a star when it came to communication/purchase and delivery. The company is Program Engineering
http://www.pro.com.sg/
and his name is Jimson Chan
Like I said earlier these were bought back in Oct 2006 hence the very cheap price
The 12x3 leadscrew I sourced from Ebay from a company in Germany and had to use bablfish for translation that company's ebay name was sternstern_0
and the drivers are from America ...Hobbycnc 200oz kit
so this router is going to have an international "birth"
PSU is a very nice item I got a couple of years ago from a real auction house for ....wait for it £2...and the best bit ...it was for three so I have two spare, more on them later
1st pic the, raw material straight from B&Q (UK's equivalent of Home Depot, at 8x4 I had to cut it while it was still on the car roof......tricky
2nd pic....no it is'nt snowing in my shed....I've just been belt sanding my "router frame"....yes it's a desk ,but a very sturdy metal framed one with a very handy set of draws at one end
3rd pic...the first sandwitch of a 3 ply laminate, which is chipboard with it's next thin coat of wood glue ready for the next ply.
4th pic 3rd MDF ply
5th pic the final 3 ply ...the desk is made of beech so I have a laminate of beech/chipboard/MDF
I hope the different expansion co-effiicients of these materials des'nt come back to haunt me, up to now the table has remained straight and true

[Gfowa]

Right you may have noticed that the date on the photo's are over two months old so I am actually a lot further on with this build than the photo's might suggest, however I am not going to spoil it by making massive leaps in the documentation of this build, I would much rather keep you in suspenders
I will try to bring my build up to date as time will permit
Why am I building a CNC router?.....the same reason everyone else does......it's seriousley cool no really I would like to be able to cnc model aircraft props and wind turbine blades.....and all the other ##ap.
Ok some more pics
pic 1 this is how I recieved my linear sliding components from Singapore, they were excellently packed by Program Engineering, all rods were wrapped in waxed paper, all bearings boxed/oiled (leadscrews were placed there for convenience ...they came from Germany)
Pic 2 my trusty Delta bandsaw £15 from a real auction, it cuts MDF like a hot knife through butter, for me, an absolute essential piece of equipment, 10x better than a jigsaw.
Pics 3&4 are back to front ...they show the end pieces of the X axis (complete with a knackered one where I drilled the leadscrew holes on the wrong side) ...where my two 1300mm rods will be located with twin leadscrews set at 45 degrees inwards of the rods which is much more evident in pic 4
If you're wondering about alignment of the two rods and leadscrews...most of it is taken up by having enlarged holes on one side only one rod is totally fixed everything else will be adjustable (slight tap of hammer then nip up or fix with CA
Pic 5 is one end of the x axis mounts being glued into place note a rebate was routed into the table to provide extra rigidity
I might get another instalment in tonight, but if not, see you all tommoz

[Gfowa]

Okay starting the Z axis with a basic frame to mount two shafts in for the vertical travel, nothing new here I'm sure this has been seen before, I've used a mortice and tenon style join for the sides for added strength, but I won't be glueing it untill the last minute.
I have been very lucky with the shafts only one duff end support.
last one was perfect with no alignment required (phew)
pic1....front view
pic2....side view showing m&t joint
pic3.... test fit of linear shafts
pic4....Blocks that will fit to the gantry sides that will support the linear ball bushings of the X axis

As I mentioned earlier using a bandsaw allowed for much better finishing to joints, as they were dead square......jigsaws do tend to wander off the straight. Another tool I have found to be invaluable has been my belt sander which I can clamp to my router table so it is 90degrees square to it then I have a machine sander, I do like an easy life, don't you?
Anyway.....I'd better go and spend some time with the missus you know ...browny points and all.....back soon

[Gfowa]

Ok I do like to jump backwards and forwards on this build as it keeps me interested rather than stagnate on one area, so with that thought in mind I'm moving on to leadnuts. Although I did purchase 3 brass leadnuts , I decided to try making some first and be able to fall back on the brass ones if needed. Well obviousley I would need a tap......so as you do I made one out of a piece trapezoidal screw thread tapering it off at one end and cutting slots along its length to mimic exactley what a tap does....cut material......yes but what material. Earlier in this thread I said I was going to use what material I had available at the time, and it just so happens I have a lot of what I believe to be 4mm thick acyrilic sheeting which was used for replacing glass in a factory window, it was free so I liked it.....freeeeeee....sounds soooo good.
So what I did was use a hole saw on my trusty Black & Decker drill to cut many circles to superglue together to make up a thickness like solid Delrin rod. these I then glued them together and held them with an 8mm bolt.
When cured I turned them down to size in my chuchhill lathe, once turned down I removed it and loosened the bolt and removed it to put it back in the lathe perfectly square so that I could put my home made tap to use by putting it in the tailstock chuck ...then sliding it forward to start the tapping.....starting the tapping this way ensures you get the tapping straight and true.....a bit of WD40 for lubrication and were away....once the tap is cutting true I take it out and finish it in the vice......oh before I started cutting I drilled four 3mm holes then used Screwfix turbogold screws to make sure the discs did not come apart I then cut off each end of the screw and ground them flat, thats the four dots you can see in the photo's. I intend to fabricate some antibacklash devices to use with these ....more on that soon......ok I need to go and push some zzzzzzzz's now so ttfn.
pic1......4mm Acrylic sheet
pic2.....the cut discs
pic3.....discs superglued together
pic4..... finishing the tapping using fabricated trapizoidal tap
pic5....the nearly finished leadscrew nut

[martinw]

Dear Gfowa,
Brilliant thread! You manage to throw out a huge volume of information in an economic way. My jaw is on the floor...

Maximum respect...and Happy Christmas

Best wishes,

Martin

[Gfowa]

Thanks Martin....merry chrimbo to yourself
would be great to see it alive before 2008 but I think that a little optomistic
regards Kevin

[Gfowa]

now to make my leadnut "anti backlash"Using the same method I made another piece of acrylic to turn down in the lathe yet again I used turbo gold screws to assure nothing comes apart, ( if it does not come apart in the lathe while being turned down, it ain't gonna come apart on the machine). Once turned down it gets the same treatment with the home made tap. Ok I have some nice 3mm pins I got from somewhere so these along with 4 springs are going to be used to preload the second nut against the leadnut. I aligned them together with a piece of leadsrew then drilled using a pillar drill all 3mm at first then when parted the second nut was drilled out to 3.5mm to allow movement that counters the backlash
Pic 1.....the raw state of the 2nd nut, triangles cos it saved space (I waste nothing)
pic2....prior to drilling the 8x3mm holes.
pic3....pins fitted to leadnut and holes enlarged on 2nd nut.
pic4..... Antibacklash nut complete and on leadscrew.
It's alittle stiff at the moment, but I'll put it through a few turns with my drill to bed it in.

[joecnc2006]

How long do you think the acrylic will last due to wear?

Joe

[Gfowa]

Hiya Joe, your fame goes before you, I'm humbled your asking me a question!
I'm not too sure really all I know is this stuff I assume is acrylic is imensly strong, last year I was cutting a 6 inch wide stip to block a gap in my greenhouse and out of curiosity I took a piece of scrap and bent it over double ...expecting it to snap.....it didn't. I bent it back and forth many times and it would not break, so I thought bluddy strong stuff this. I've used it many times for mounting things and it has never failed on me, so I figured it would be good for this job but if it isn't in the long run I can always replace them with brass or delrin

[Gfowa]

Right so I have a few more of the A/B nuts to produce, but for now time to move onto something else.....gantry sides I think
pic 1.....gantry sides double thickness (36mm) cut on bandsaw and now curing under the wieght of three car batteries
pic 2....ball bushings mounted into blocks and blocks glued into gantry sides
pic 3....both sides mounted,but only held by a piece of STRING
pic 4....here comes that acrylic again, this time the inner hole has been drilled out using a 20mm flat wood bit at low drill RPM. These are going to be the shaft supports for the y axis
I will be using another piece of MDF across the back of the gantry sides to add extra rigidity.
The x axis shafts are loosly placed at the moment......you know how it is ....you want to see what it looks like, that gratifying smugness that wells over you when you begin to see a familiar shape.......whoooof getting carried away now... better get myself a can o beer to bring me back down to earth......I hear my shed calling me now so ttfn
kevin