Has anyone built Isaac as a repstrap?
May 12, 2010 06:03PM
Hello All

Following a BBC News article on 3D printing a week or so ago I have been devouring everything I can find about reprap. Of top quality is nophead's blog which I read from start to finish (although I must admit the more techy stuff about EM noise etc. went over my head and I skimmed that). Nophead, if you read this I must tell you you are a god when it comes to research and documentation in a way that will (and I am sure has) move the reprap project forward in huge steps. Respect smiling smiley

Dividing the requirements of Mendel into 3 broad areas. Electronics, Repped parts and rods/fasteners it seems the plastic parts will be the most expensive to source. - I am in the UK and it seems there are few operating printers here.

Anyway, I have decided I want one and have looked into various sources but the most difficult and potentially most expensive portion will be the printed parts. To overcome that expense I am now considering a repstrap and have found a potential candidate in the form of Isaac provided by FlemmingCNC.

I am generally a HS (I assume that means someone off the High Street) person and do not have any electronics, CNC, robotics or any other construction experience. I am an IT consultant (out of work the last 14 months due to the downturn - so I currently have time) so do have a systematic mind and the ability to RTFM.

Anyway, to the point of this post. Has anyone not related to FlemingCNC built this beast? The build docs are currently incomplete and I am loath to start something that is not proven.

sorry about the long post for a short question, but I guess an intro slipped in somehow.

Re: Has anyone built Isaac as a repstrap?
May 12, 2010 09:09PM
I also think printed parts are too expensive, and when I want to build one, I plan to build the ponoke repstrap. it uses lasercut parts.
Re: Has anyone built Isaac as a repstrap?
May 13, 2010 01:41AM
I (and a group of friends) bought a set of the parts and have been building it. All of the parts are quite well-made, although there are a few finish issues (but nothing major). We're pretty much done with the hardware build, and we're about to actually test it. At this point, we think it'll work fine, as each of the axes seems to move smoothly after a bunch of tweaking.

I would link you to our build log, but we're lazy and haven't actually done that yet...
Re: Has anyone built Isaac as a repstrap?
May 13, 2010 06:13AM
Not an Isaac. but for your info nophead has a set of mendel printed parts for sale on ebay at the moment see [cgi.ebay.co.uk]
Re: Has anyone built Isaac as a repstrap?
May 14, 2010 02:30PM
Hey Kieth

Yes, I saw that... unfortunately bidding did not go my way sad smiley

malesh - such is life

I am thinking the Isaac option may not be right for me for 2 reasons. First shipping included brings it to $290 which is already close on £200 and then I need to add customs - 17.5% VAT + 2.5% flat rate for goods under £630 so 20% by my understanding see UK customs import charges, which brings it to roughly £340 (excluding mail handling charges) and that brings me to my second point: It still is not a mendel(*) so I would have to go through the steps of converting it to a mendel.

(*)is it mendel or a mendel?

So I will either look at designing a base of easily produced by simple hand held home tools and no workshop or continue to source parts locally. This does not interfere with the sourcing the components of the other major areas.

Problem is I seem to be moving from buying a 'distributed' kit as in completed electronics and completed RP parts to doing the electronics myself (you may ask where is the problem in that, but it is that I do not have any electronics experience... am reading up on it. Talk about a brain workout lol. Influencing factors depend on costing individual parts and bonus would be better placed to maintain and improve my printer..

I babble somewhat spinning smiley sticking its tongue out
Re: Has anyone built Isaac as a repstrap?
May 15, 2010 10:31AM

(*)is it mendel or not a mendel?

That's a bit of a loaded question. It isn't a Mendel in terms of the pieces; very few of them remain intact from the original. We had to change them in order to be able to machine them. Look at some of jupdyke's work on this forum and you'll see the same thing.

In terms of the whole, we think it is a Mendel at heart since it:

  • can print it's own parts
  • can be replaced an axis at a time with original parts (just add time and a few nuts/bolts)
  • has the same dimensions
  • has the same build area
  • uses the same hardware (just less) and electronics

As far as VAT goes, I feel your pain but there isn't much I can do to help yet. But if you have any ideas we are all ears.

Isaac: a CNCed Mendel Derived RepStrap
Re: Has anyone built Isaac as a repstrap?
May 15, 2010 11:41AM
bfleming Wrote:
Look at
> some of jupdyke's work on this forum and you'll
> see the same thing.

Is that true? I got the impression that judyke milled the parts he could rather than re-designed them and the parts he did mill would be the same with the exception of the thickness.
Re: Has anyone built Isaac as a repstrap?
May 16, 2010 06:47PM
Some parts, y-motor, y-idler, clamps etc are all easy and jupdyke left them alone alone as did we. But if you look at his z-motor (post dated March 30, 2010 04:34PM), and ours for that matter, there are not the same. But all 3 serve the exact same purpose, and are all 100% compatible as far as spacing between the vertical rods and the frame where it really matters. The cross rods don't matter other than to support both sides, so he got rid of two of them as did we.

Having 4 rods made since if you look at the 'why' of the Mendel. It was build with parts small enough to print on a MakerBot. They needed 4 rods to properly support the 4 major parts. We didn't feel the need to keep that restriction thus lifting a heavy design burden. Our parts, and I'd wager jupdykes as well, can be printed on a Mendel sized printer if need be.
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