This post is going to self-destruct soon....

Here's absolutely nothing to do with my repstrap. Can you guess what it is?

Yep, I grew a big turd!

(This post will be removed unless I get requests for it to stay...)

Kindness and monkeys

During the bank holiday weekend just gone, I went to B&Q. Among other things, I wanted to see the welding tips, as mentioned in the forum, as potential extruder nozzles - with 0.6 mm nozzle and a 6mm diameter at the other end. Had to ask where they were. When found, each packet had fewer in than the 5 claimed - and one or more holes in the plastic bags. The staff member (the same guy who had helped with my trolley early on (Mark)) muttered "thieving monkeys" and offered to reduce the price. He put the remaining contents of two bags into one, and priced the 4 welding tips at £2. So I've got four welding tips. I also bought three small G-clamps I'm sure will come in useful in this project somewhere. The purchase went on my partner's card, so I don't have the cost breakdown on me.

Meanwhile, I have received offers of practical help from members of the forum. You know who you are, and thank you. I was quite taken aback, and touched, and didn't know what to say, so much so that those involved contacted me again to check it was OK! It is so good to find a(nother- it's my second) forum where everyone offers encouragement and helps each other without the nastiness so endemic in many fora.
So, if you're thinking of starting a repstrap/reprap, do it, and be assured of positive input. And if someone offers you help, reply straight away!

Today I have opened my email to an email from the RRRF store notifying me of the despatch of my order (from the 18th May) yesterday, the 28th May. So that's 10 days already, before the long-haul delay swimming across the ocean......

Soldering kit

I bought a 30W electric soldering iron and some associated kit today.

Maplin sub-total = £20.66

• 30 W electric soldering iron, part number N38AC, £6.99
• set of 3 tips, part number N00FB, £4.49
• soldering iron stand, part number FR20, £5.99 (meant to get BP57M, £4.99, but couldn't see it)
• desoldering braid, 1 mm, 1.5 m length, part number N48FX, £2.29

and my first electronic component:

• 100 k thermistor, part number CR05F , 90 p!

Running total (excluding last set of washers and screws from B&Q, and the PCBs yet to be finally costed) = £171.42

Motor mounts

I had previously fixed just the x-motor, but hadn't given a diagram of the positions of its screwholes on its angle piece (motor mount).

I have cut another piece of threaded rod (12 inches) for the z-stage, because I had stolen that one for the y-stage.

Today I drilled all the motor mounts, so here are the position diagrams.

I've not yet finalised the diagram for the z-stage.

Guesswork

I have cut the upright today, guessing its required dimensions. It is a piece of wood 38 cm tall by 4 by 4.5 cm with a slot cut across the top to accept the furniture leg strut I cut yesterday.

Timber!

Nothing to do with collapse, yet, but I've prised off the black plastic foot from the furniture leg, measured the inside and I've cut a piece of waste timber to fit. This was stuff stored in the loft from when we domolished a false wall ~8 years ago. I am a little concerned to see a couple of woodworm holes in the timber, although not in the section I've used here. I guess we should check the roof timbers now.

The piece I have cut is 2.2 x 3.5 x 18 cm. I sanded off the splinters, and was delighted to find it fitted first time, slotting straight in with very little play, and I hope the fit is tight enough. I don't know yet if this piece is long enough, so here comes some more development work. Ditto with the height of the upright support timber. I may not know until I have my extruder fitted to my z-stage - it depends on the size of the extruder I use, I think.

Phew!

Firstly, the extruder motor I ordered yesterday has already arrived! Wow, that was fast.
Also I have now managed to make my Makerbot order - I had tried removing all the security and privacy and pop-up blocker settings, and I'd tried Firefox instead of IE7, but in the end I did all of the above as well as turning off Norton Personal Firewall. That was really a last resort.
I had watched their stock dropping, down to only 2 motherboards left....

Anyway I have ordered:
motherboard 1.1 kit, extruder controller 2.2 kit, three motor drivers (I so want to say 3.3, but actually they're 2.3) as boards only, and a temperature sensor v2 board only.
The Makerbot charge comes to £58.11 inc postage (so far) with current exchange rate.

I have spent much of the day looking at soldering irons and solder paste. There is a lot of choice out there, only I didn't know what features were important. Thanks to some help from the forum, I now have a much better idea. I'll order it as soon as the first electronics turn up.

Oh blogger!

I have ordered a Solarbotics GM3 motor for the extruder from a UK source: Active Robots! £7.99 inc P&P

Running total = £ 150.76

But I dithered about the electronics too long. Remember my table of what was available? That was only on the 15th (today being the 18th) and now the RRRF has sold out of the Generation 3 motherboard (just the board) and the stepper motor driver boards.
I'm ordering the 3 opto endstop boards and the noise suppressor board for the extruder motor from them NOW.
I'm ordering from Makerbot: 3 stepper motor driver boards, and (gulp) the extruder controller and motherboard as full kits NOW. That definitely gives customs the flag.
This is going to be expensive!
Just checking out now....
....
....
RRRF charge comes to £9.70 inc postage (so far) with current exchange rate.
Makerbot = problem. The checkout procedure won't go beyond selecting a payment method - nothing happens. Oh-oh. I have emailed customer service. I hope these items don't sell out before I can order them or I'm well and truly stuck.

Shuffling on the spot

You hope you're going to remember everything, but you don't!
I put together the springy/wheely bit of the z-stage, and mounted it on the 'vertical base'. Wondered why it sprung straight off.

Oh yes, I remember now - I need to raise the rails to allow for the long screws on the stage.... I knew this back when I did the y-stage.....

Yet another disassembly, cut the strips, reassemble, realise the rail screws need to be swapped to longer ones as well, re-(re re?) disassemble, reassemble.
I've been cheating and using an electric screwdriver. I've run it flat again.

It occurs to me that a picture of my marking box would be in order, so here it is. I tried to get pictures showing the PTFE disks in various stages of marking up, but the brilliant white sets the brightness settings on the camera all wrong so that the marked lines cannot be seen. Anyone know how to take photographs involving brilliant white without losing dark/fine detail/colours?


The friction seems to be lowest with the most perfect disks on the outside of the rail and the others moving with the springs.

Short back and sides

Having assembled the z metal framework on the landscape oriented 'vertical base' (v.b.), and realised that its side to side dimension needs to be the same as the portrait oriented z-stage, I have marked out the z-stage with the same hole positions as used for the x-stage (except the pipe clip - I have to see where I can fit that afterwards). This means that I could measure directly off the x-stage to determine how far over the track-rail the stage overhangs, and use this as a guide to mark the cutting line for the left (track-rail) side of the v.b.. Then I've measured 8.5 " (= side to side of the z-stage) from there to mark the cutting line on the other side.
The plan is to cut 3.8 cm off the left and 2.7 cm off the right of the v.b. in effect making my v.b. a square.
In order to line up the edge with that of the stage, if the v.b. is a little too short in the end, I shall place the angles just outside the edge, if a little too long I'll sand a bit off.

More changes

I have assembled the z-rails on the 'vertical base'.
Remember how I'd decided to turn the 'vertical base' around, to landscape orientation? Well, I drilled my holes like that for affixing the z-framework (mark the holes on the right side through the assembled framework, start drilling from that side but remember to countersink from the other side) and I thought all was well until I realised that the final pivot arms actually go past the edges of the 'vertical base' (v.b.) and the z-stage. They are attached to the final angles, which are attached to the v.b. and extend to the front of the z-stage so it can't fall off the v.b..
So I need to cut the sides off my base now.

Talking about blurry

I've started to consider the z part now, but, as usual there is something wrong.
In (http://www.reprap.org/bin/view/Main/McWire_Cartesian_Bot_1_2) the BOM for the z part states 24 for the rails (ie 12 inches each). Mine are cut to 13 " each, as per the 'Cut aluminium rails to length' instructions.
The so-called vertical base appears to be the same size as all the stages throughout the webpage.
However, if I put my z rails up and down a portrait oriented vertical base (being 11 " tall as per the 'Acrylic cutouts' section) the size of the aluminium angle means that it doesn't fit over the MDF - it catches the edge, whereas the McWire picture shows a large gap bottom and top. My aluminium angle is 3 cm deep whereas the McWire's is 1.5 ", which is actually larger. So the problem is not due to the size difference of the angle.
Hmmm.
Is the vertical base actually landscape? It really doesn't look like it, even when I zoom right in to the http://www.flickr.com/photos/hoeken/2293533001/sizes/o/ Flickr picture.

I can only assume that the rails need to be longer. But how much longer?
Maths guess: 11 " vertical base + 1.5 " angle + 1.5 " other angle + gap = ~15 "

Now, I've used 94 " of my three lots of 1 metre u-shaped channels (117 ") so there isn't enough left (maximum 13 ") to re-do these lengths. So now what? Does this mean the z-stage doesn't have its full range of movement?

For now I shall have to turn the vertical base around to landscape orientation, stick with 13 " rails, and probably have to cut a new z threaded rod to 12 " because I've nicked its intended one for the y-stage (instead of the 18 " one I'd cut for that).
I may have to buy some new rail and cut a new board (unless the holes aren't in inconvenient positions when turned around) if I need a bigger range of movement. I guess this will have a knock-on effect on the software settings, too.

A flurry of photo's

I'm too tired to go out looking for tubing, and too tired to work out how to do the z stage/"vertical base", so I've taken Renoir at his word; it doesn't matter what the background is. (Bet you weren't expecting a trampoline, though......)

My photography skills aren't, so apologies there. I don't have steady enough arms for my current digital camera, and often get blurry images, which I didn't with my old film one. (Some of you will have an inkling of why I find this less than easy....and why I'm nervous about the soldering thing, although I do have steady hands...)

I'll get anti-everything for my next camera. Hope the pictures give you a flavour if you haven't already got it. I suspect most of the followers already know what's what.

Here was supposed to be a photo' of my base and one of the x stage only they don't seem to be on the camera - as I say, my photography skills aren't. So here instead we have a blurry close-up picture showing the extra strips of MDF I added to the rails attached to the x-stage to give the y-stage enough clearance:

Here is the y-stage:



(cunningly hiding the error hole)

and here is the top surface of the y-stage (anyone want a spare hole?):

Here is another blurry picture showing how the two washers fail to raise the pivot arm off the stage - I need those penny washers:


Here is a picture of the x-stage assembled on the base:

and here the y-stage covering the x-stage, both assembled on the base:

The base isn't finished yet - it needs its upright at the back to hold the z assembly, and I may need to move the x/y stage assembly backwards on the base. The screws/nuts have not been tightened, since disassembly seems to be a regular feature of my build! The y-motor isn't yet attached to the framework, and the x-motor isn't attached to the threaded rod because I have no suitable tubing. And no, it doesn't look like anything - YET!

Blogging with tables

I had sudden inspiration about my table problems - look it up on Google!
I was getting a huge gap before scrolling down to see my table on the previous post, and no matter what I tried with the HTML, I couldn't get rid of the gap.
Anyway, thanks to (http://www.bloggertipsandtricks.com/search/label/tables), I've got it fixed now. So thanks to Peter@Enviroman, Nitin, and http://mlawire.blogspot.com/2007/01/table-formatting-in-blogger.html.

I know where to go next time I have problems.

It's all very dark

I've been trying to take photographs, as I've been hassled about the lack of them, but no go so far. I tried to take some with the camera that is on my laptop, so I could angle it at the subject AND see on the screen what the outcome would be, but the "camera" screen is just black. I've checked through the Readme and all the troubleshooting information, got someone else to go through it, too, but all I can conclude is the camera no longer works. I haven't used the camera since 2005, when it worked fine.

This means I need some help to take the photo's, but my willing helper turned out to be not-so-willing when I asked that the parts be held up against the wall as a blank backdrop!

So for now, sorry folks, I'm stuck.

Ditto with the electronics.

I am looking to get the 3rd generation electronics. The boards + components (in kit form only) are only available in the US and the costs put me above the customs threshold, even if I make the orders from the 2 separate sites. And not everything is available, anyway.

Here is a table of the current state of play:

Part	RRRF org shop		Makerbot
	Full kit	Board	Full kit	Board
3rd generation motherboard - v 1.1	--------	$10	$40	-----
stepper motor drivers - v 2.3 (times 3)	--------	$2.50 x 3	$20	$3 x 3
opto endstops - v 2.1 (times 3)	Link says “product not found”	$0.50 x 3	Out of stock	$1 x 3
extruder controller - v 2.2	-------	---------	$30	--------

I am considering having to buy just the boards abroad, and try to get all the components here. Talk about rapid learning as I've never done any electronics like this.

I have been reading the section on "reflow" soldering (http://reprap.org/bin/view/Main/HotplateReflowTechnique), and trying to find a hotplate - we only have a gas cooker/stove (not a good idea!). Argos only has a double one (with several reviews saying it died very quickly), ditto the camping sites. The single ones on Ebay work out around the same price as the Argos double one. I'm still hunting a cheap and reliable version.

Almost right

"There's a hole in my y-board, dear reader, dear reader,
there's a hole in my y-board, dear reader, a hole."

Now reassembled - but it still doesn't work - the pivoting arm hits the PTFE slider where I've drawn it. Luckily, I haven't got around to glueing it yet.

So here is the amended y-stage diagram:
They need to be right up in the corners (or cut them shorter).

Did you see that?

Two problems - did you spot one?
The pipe clip should be on the opposite side according to the McWire instructions. I know I've seen it the other way round somewhere - hold on whilst I go looking...

.... yep it's on the Makezine version (http://blog.makezine.com/archive/2007/11/make_a_repstrap_part_2_we_1.html). Y-motor at back. I'm trying to figure out if that matters, having the motor at the back instead of the front.

The other problem is yet another error - I've put one pivot-arm's pivot screwhole in the wrong place. (How did I manage that?!)
I'm getting to be quite a dab hand at disassembly....

On another front, people keep asking me what I'm planning with the electronics to control this thing - well, having seen the Paperduino (http://lab.guilhermemartins.net/?p=817) I'd like to be able to make all the boards in a similar manner. Only I haven't a clue how! The boards required are not available in the UK, so I'm short of options. If I buy from the US, I'll probably get stung for import tax (~15 %) + handling, so I'd rather find a local/European supplier.

The fix

I've cut four new strips of MDF, and put two under each y-rail. All is re-assembled now.

I have also drilled all the holes in the y-stage, using as maximum the 4 mm drill bit and all the screws are in - all are 5 mm screws. I have drilled out the y-pivot arms, too.

Here is the diagram of the y-stage - the pivot arms are identical to the x- ones

The springs I've used are the 4.0 x 79.4 mm extension springs from the multipack, using 2 together per stage to make up the right length.

Ooooooooooops!

Well, I said I'd post about errors. I've just come across a teeny weeny little major problem.

Given that I ended up using 3 cm screws for attaching the PTFE disks to the underside of the x-stage, necessitating removal of part of the baseboard to provide enough clearance, that means that my y-stage isn't going to slide over the x-stage. Ooops. Should have thought of this earlier.
Now I know why the other B&Qer used bigger u-channel (ie taller rails).

I have several options:

• buy bigger channel (2.5 cm instead of 2 cm) and, basically, start again
• use the PTFE sheet (3 mm think) instead of the MDF (6 mm thick) to make the pivot arms
• cut my disks smaller (and I only did all the cutting of those yesterday - cutting them thinner will be difficult to say the least)
• put a strip of MDF under the y-rails to raise their height (adds 6 mm clearance) - probably the easiest option, although insufficient (use 2 strips??)
• all of the above to get enough height?!

I wonder if I'll have to do this for the z-stage as well?

"Ooooow.....

....ScrewFix"!! (Pardon my French)

I thought I'd struggle up to ScrewFix today to get more washers, and to try out penny washers, now I've found them on their website. Problem was they're not down as 'penny washers' in their catalogue - there are 2 different products labelled 'large flat washers', so I had to guess from the pictures.
And I get home to find I got it wrong! Grrrrr!


Anyway, here are the diagrams I finished yesterday for the x-stage and pivot bars:



The y-stage diagram still needs its PTFE slider positions adding.

Toddling along

I forgot to say that I have now cut the excess off both sides of my baseboard - I did that last week. I have an amended diagram to reflect the changes. I'll keep on amending it, though, until it is right, as I still have some development work to do with the rear upright post. At that point I shall put the diagram up on the blog.

After a lovely weekend away, I didn't have the oomph to walk up to ScrewFix, so today, in the sun (and wind) I cut all my other PTFE disks from the rod. The picnic table, which is slightly too high for me to get up onto its seats easily, makes a good workbench - it already has gaps ideal for sawing! I cut and marked some more MDF pivot arms, too, for the y- and z-stages.

I then marked the y-stage for the disks/arms. I spent the rest of the time drawing out the diagrams for the x-stage and y-stage hole positions and glue positions. I have nearly finished - just want to check them over before I post them up.

I hope to go out tomorrow, because I can't go much further without more 5 mm washers.

And yes, it's time to do piccies. I need to find a suitable backdrop and/or floor to present clear photo's.

Pet shop blank

I went to my local pet shop (~200 m away right at the end of my road) today to ask about tubing, but they only do one size, and that looks to be about 3 mm diameter.
Hmm. Trying to think of somewhere else I can try. I only need about 15 cm, if that.

Retailers

The thing with B&Q, like many other retailers, is that they have now bar-coded every individual item. This means that 1 m long and 2 m long items have their own sticky label bar code. I cannot peel the labels off the channels/angles at all, and although the ones on the threaded rods come off easily enough, they leave their sticky behind. Not what you want for freely-moving nuts on threads.
I tried household soap, then detergent (washing up liquid), then a cleaning gel, and finally a spray containing ammonia, well brushed in with a toothbrush. This finally worked. However, on threading the rod through a nut I found tiny balls of grey glue were forming deep in the thread. I have removed all of these with my fingernail.

I have now attached the motor, using 3 mm screws, 1 cm long, each with 2 washers. The mounting holes are 4.4 cm apart. I used a 5.5 mm drill bit for the motor arm and a 3 mm drill bit for the 3 mm screws. I just need some tubing......

Changes

Yep, the x threaded rod was too long. I have now cut it back to 51 cm. (And yep I've changed units again!)

I have wrapped my 8 mm nut in electrical tape to seat it firmly in the 15 mm pipe clip, and it took about 15 " of tape to do so - rather more than I expected. I wondered if this had to have some give, or whether gluing it may be a good option?
I have bolted my pipe clip holding the 8 mm nut to my x-stage, and am now ready to sort out the motor.

I still need to cut the extra off the baseboard, but thought I'd do this when I disassemble the x-framework to mount the motor.

Also, I have started a Wiki, which should eventually contain complete instructions, parts, costs, pictures and diagrams. Consider this blog as my lab. notebook, and the Wiki as my SOP/method for someone else to follow step by step.
I'll post links when it's in a fit state to use.

Cheaper

OK, it's only a small component and a tiny amount of cash, but if anyone wants to do this on an absolutely minimum budget, I have just found:

• 15 mm chrome-plated Cu pipe clips, pack of 10, part number 17694, £1.53 from ScrewFix,

(instead of what I bought (u-shaped clamps = 15 mm saddle clips, pack of 10, £2.18 from B&Q).

Fiddly bits

So much for using two washers between MDF surfaces.
Instead, I now have one 8 mm washer (wider) between the stage and the pivot bar, but two 5 mm washers between the MDF and the PTFE, which prevents the disks from rubbing against the MDF where the disk thickness isn't perfectly uniform. In order to fit the extra washer, I have had to swap the disks' screws to the 3 cm length. I now have freely spinning disks, but the pivot bars are not so free. Net result, though, is much less friction.
One advantage of the extra washer is that the disks are now better aligned with the rail when the PTFE slide raises the x-stage slightly above the rails.
Now to sort out some feet for the assembly, once I know how much drop I need for the motor.....

More development....

...and more errors!
Bending over the tops of the pins holding the springs worked well. The trick was to make the bend-point somewhat higher than the spring. However, I have had to remove one of the washers between MDF layers because two left the pivot arm wobbly from side to side. If only I could find a washer with a 5 mm hole but bigger outer diameter....

Also, on trying out my sliding x-stage, the nuts of the pivot arm holding the PTFE disks hit the base board either side. I shall have to cut away another 2 cm each side. Even then, I shall have to put the whole assembly on feet so that the ends of the screws don't touch the ground.

The locations and the design of the pivot arms works, basically, but there is currently more friction than I would like, and it's not to do with the lack of PTFE slider, unfortunately. I don't know if the friction is too great for the motor or for smooth movement, though, so I shall work on it some more to see if there is something simple I can tweak, but otherwise I shall leave it until it goes motive to find out whether it matters.
On that front, the stepper motors arrived today.

Research

I have been finding out about washers. I have MDF pivot arms, holding PTFE disks (instead of bearings). To enable my pivot arm to rotate freely, I shall put 2 washers between the MDF surfaces (because both are poor turning surfaces), and one between the MDF and the nut on the arm's pivot and between the MDF and the PTFE disk and between the PTFE disk and the nut.
As an aside, apparently steel makes a good turning surface but aluminium does not.
I shall use 2 nuts together for each of the bolts on the arm's pivot and the PTFE disk.

Development work

I've drilled all the holes for the frames of the other stages now - only the extruder and bearing arm mounts still to do. When positioning the frame onto a stage, it was easiest to make the frame and then mark through the frame's holes onto the MDF.

I have also started design/development work on the bearing-substitutes and the required positions for the pivot arms with the springs that I have (not 4 ").

I have had a lot of difficulty with the little pins that hold the springs - they twist around in use and the spring slips off. I think it is because the MDF (unlike acrylic) gives a little. I am going to try bending the pin right over to prevent this happening. If my pins are long enough.

I went back to B&Q yesterday - they have lots of countersunk bolts of all different diameters and lengths, in packs of 10 including nuts. These are not labelled/found on the website under countersunk/countersink.
When I have worked out exactly which bits I'm using, I'll put the relevant parts and costings up.

For cutting the PTFE rod, I used masking tape to mark the location of the cuts. This also prevented any skating of the saw from damaging the round surface of the rod, which will be essential to act as low-friction "wheels". In order to drill a central hole, I made a little box of glued-together MDF (the same width as the diameter of the rod and approx the same height as the disks I'm cutting), which enables me to mark the centre of the circle (across the diagonals of the box) very easily, using the disk in one orientation and then in a second orientation 45 degrees from the first. (Perhaps a photo' and/or diagram would help here....)
I used a centre punch, then 1.5, 3.5 and finally 5.5 mm drill bits for my centre hole in the PTFE. The holes were pretty darn close to central. I'm now thinking of marking the centre of the box and drilling a marking hole through that - I may even be able to drill a disk through it if I can find a way of holding the disk so it doesn't just spin with the drill bit....

If at first you don't succeed...

And if at second you don't succeed either....
OK, if you're trying to put a countersunk 5 mm diameter bolt with a 9 mm diameter head into MDF, use a 4 mm pilot hole and a countersinking marking line of 11 mm diameter.
I've finally got it right now!

(I wonder how many of these sorts of things you are taught/pick up/learn if you get the chance to do woodworking/metalworking at school?)