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PostPosted: Mon Dec 09, 2013 2:50 am
by SheldonE
For those of us in metric zones, what would be the appropriate measurements for the lead screws? 7/16" is a bit over 11mm, so a 12mm might be the way to go, but what about the spec for the thread?

Re: Metric?

PostPosted: Mon Dec 09, 2013 3:53 am
by Nicholas Seward
You have to find a supplier. If you can provide some local links I would be glad to pick what I think is the best option. Cost is usually a problem.

I found this UK link. I have no idea what the cost is.

I would go with with a root diameter of 8mm or more to get the rigidity you need and a lead of 25mm or more to get the speed you need.

I found a 10mm 28-start with 1.25mm pitch. This gives you a lead of 35mm.
I also found a 12mm 5-starts with 6mm pitch. This gives you a lead of 25mm.

I am quite sure these will be very expensive when you include you nuts. You would also have to reverse engineer the thread form for the thread clamps.

Here is the really bad news. For fast travel threaded rods there is no such thing as a standard. Every manufacturer has their own standards. (You have to get the nuts and the thread from the same place.)

*We can use a standard 1-start trapezoidal thread and use a belt drive to speed it up. This obviously more expensive. It is also less efficient.
*Have the ROTON screws shipped from the US. It should be fairly reasonable shipping.
*Find a local fast travel screw provider. (Again, if you provide me links I will pick out screws that I think would work.)

Re: Metric?

PostPosted: Mon Dec 09, 2013 4:02 pm
by Nicholas Seward
Okay. I did some sourcing and I am considering changing the design to make it more international friendly. IGUS has some sweet screws. They have a 10mm one with a lead of 50mm. I have a RFQ out and I will let you know what they tell me. I am also unsure what the root diameter is of this but I suspect that it is good enough.

I also have requested that ROTON sponsor me so we will see how the dominoes fall. I figure with the simplicity of the build that 100s of people will build a LISA in the next year. I thought ROTON might like to slap their logo on my PVC uprights. After I paint everything to look cool of course.

What are your thoughts? What would be the best way to go for this design?

Re: Metric?

PostPosted: Mon Dec 09, 2013 9:51 pm
by SheldonE
Well, I was just looking for a suitable metric replacement lead screw. I wasn't really expecting to see a re-design and sponsership deals. If your comfortable with it, go for it. Personally, I'm still struggling to get a Prusa i3 together (I'm wood working challenged). I was planning on using it to build a Rostock, then I saw GUS, then LISA evolved. So I'm still kinda weighing my opions.

Re: Metric?

PostPosted: Mon Dec 09, 2013 10:23 pm
by Nicholas Seward
Currently LISA is the easiest one to operate and has the best dimensionality of its prints but it also costs the most. Of course it should be cheaper than a Rostock.

I just got off the phone with IGUS and they will have to order the parts from the factory so pricing is a little iffy. They quoted me $80 for a 600mm long 10mmx50mm lead stainless steel. The steel version could be much less. (1/2 as much if they price like everyone else.) If they come back with $40 then they are in line with ROTON. I also asked about nuts and what the backlash was. I should know more tomorrow. I have always been impressed with IGUS's pricing before. I am sure I can haggle with them. I will give them the ROTON price and ask them to beat it.

Re: Metric?

PostPosted: Tue Dec 10, 2013 12:07 am
by Cozmicray
I would vote for Metric Lisa.

Wally was all metric (I think) measurement and fasteners.

All my experience with a number of printers have all been metric

Marlin works in mm?

Standard in my sketchup is mm.


Re: Metric?

PostPosted: Tue Dec 10, 2013 1:33 am
by dannydefe
I'm okay with metric depending on the price, Roton Seems to have good prices. I actually had the IGUS salesmen in my shop a while back exploring screws and slides, I came away with the overpriced burning feeling in my wallet.

Re: Metric?

PostPosted: Mon Dec 16, 2013 8:42 pm
by Nicholas Seward
I heard back from IGUS and that is a no go. You will be better off paying for the shipping from ROTON. Every individual screw and regular nut was quoted as about $100. The anti-backlash nut was quoted at $120. $600 just fro screws and nuts is not acceptable to me. Roton is less than 1/2.

Any other ideas on global screw providers? I would like this design to be metric.

(We really need to test the threadless ball screws. That is by far the cheapest solution.)

Re: Metric?

PostPosted: Mon Dec 16, 2013 9:53 pm
by SheldonE
The threadless ball screw is probably the desired option if it works. There seems to be a few people posting videos on YouTube experimenting with them.