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....and it begins!!!!!!! (mcwire build)

Posted by SCphotog 
....and it begins!!!!!!! (mcwire build)
December 16, 2008 02:41AM
Yesterday I bought most of the materials for my McWire build that you can purchase at a hardware store. I got the iron pipe from Home Depot as it was almost $13 cheaper than Lowes. They had everything in stock but the guy working the plumbing dept. told me that they could cut me any length I needed and thread it for me on the spot at no additional cost.

I bought a full sheet (4'x8') of neon green 1/4" Plexiglas (perspex for you blokes across the pond) from a local glass shop that a member of my family happens to own. So I got it for cost plus a few beers at the new years eve party we will be having.

I went to Harbor Freight Tools and picked up some build essentials such as heat shrink tubing, some 18ga red and black wire, a little plastic box with about 500 springs in it and picked up a counter sink set. I found the counter sink set over by the mini metal working mill they sell. had several sizes in it including the required 82 degree one. I also picked up some loctite for final assembly.

While at Home Depot I picked up a 2'x4' scrap of Ebony Star Laminate. It is a Formica type kitchen counter top laminate that we use in the astronomy world as a bearing surface to mate PTFE bearings to. This produces a super smoothe and slick slider bearing that has excellent wear properties. I have this combo on both of my telescopes.(Orion XT 10 Intelliscope and a 16" Meade Lightbridge) I am thinking of laminating the Ebony star to the surfaces that are going to mate up to the PTFE bearing surface. This should produce much less wear than the metal to PTFE junction that we are using now.

So the cost break down.

Home Depot:
3x 1"x12" iron pipe $4.26 ea
2x 1"x6" iron pipe $3.02 ea
1x 1"x3" iron pipe $1.58 ea
2x 1" iron pipe caps $1.38 ea
3x 1" 90 degree $1.86 ea
1x 1" t fitting $2.05 ea
1x 1"x4" flange $6.95 ea
1x 2'x4' ebony star $7.50 ea
1x PTFE pipe tape $0.99 ea
2x 5min epoxy $2.95 ea
1x 30 second epoxy $3.99 ea
Total $56.12

Glass shop:
1x 4'x8' plexi $26.00
Total $26.00

Harbor Freight Tools:
1x heat shrink kit $3.99
1x 50' 18ga red wire $2.95
1x 50' 18ga black wire $2.95
1x spring kit $6.35
1X countersink set $15.99
1x 2oz blue locktite $2.95
1x 2oz red loctite $2.95
Total $38.13
Grand total so far $120.25

I am figuring I will have about $100 or less left in mechanical parts left to purchase. $150 left in electronics and $60-$90 left in motors to buy. $20 to Wade for some printed extruder parts, $35 to Brian for machined extruder parts and another $20 for incidentals. That should put me in the $530 range at the highest for the mcwire build. While this seems high I will be moving the electronics, extruder, motors, bearings, and lead screws over to the Darwin I will build so The cost for the Mcwire is not that bad. I do plan on rebuilding the McWire with NEMA 17 sized steepers and using it as a CNC Mill for acrylic and wood working projects in the future so even the McWire frame investment is not lost.

Stay tuned for more updates and photos in the near future.
Re: ....and it begins!!!!!!! (mcwire build)
December 16, 2008 11:14AM
Ah, sounds good!

I especially like the Formica stuff for your mating surfaces...sounds interesting. Though, I have a functional McWire--except for the heater barrel right now which is being replaced--and I have seen absolutely no wear on the PTFE strips. Hopefully it doesn't develop in the future but if it does I'll remember your little tip.

Do you already have the skate bearings and the nuts and bolts for this thing? Other than those, you sound good to go. I look forward to seeing your progress.

Re: ....and it begins!!!!!!! (mcwire build)
December 16, 2008 01:14PM
Post your progress here. I'm going to be building a McWire as well. I'm getting all the electronics, motors, and laser cut acrylic pieces for Christmas. Once I get the electronics working, I'll head to the hardware store and get the rest of the stuff. I also plan on using it to produce the parts for a Darwin, then transferring the electronics etc. over. Good luck!
Re: ....and it begins!!!!!!! (mcwire build)
December 16, 2008 03:52PM
A quick note on the Ebony Star laminate.

It is manufactured by Wilsonart Laminate and is part of their premium line. The product number is 4552-90.

We use it in the astronomy world as a better bearing surface than what comes stock with our dobsonian telescopes. The loads that are places on top of this Laminate to PTFE bearing are anywhere between 30-75lbs and while it sees more bump-stop-bump-stop movement than any long or prolonged movement it still would serve us well.

The Ebony Star from Wilsonart is a must for it to work tho. Some physicist who also happened to be astro junkies like me did test on what would make the slickest but also smoothest bearing surface for their dobsonian telescopes. They tried numerous surfaces that mate to PTFE and even tried a PTFE-PTFE combo. In the end Ebony Star had the best properties across the board. Its secrete lies in is unique surface texture combined with the super hard composition of formica type laminates.

I have had Ebony Star mated to PTFE on my 10" scope Weighing in at about 75lbs for the last 3 years. During that 3 years it saw heavy use the first 2 years (just about every clear night we had) and moderate use for the last year. I took the ground board off of the rocker box the other week to replace a leveling screw that had fell off. Neither the Ebony Star or the PTFE showed any signs of wear. It is also on my 16" meade lightbridge weighing considerably more and it has been on it for just under a year and no signs of wear are present.

I have 12 samples I got from the store. They are 1"x1.5" samples. If anyone wants one of these samples just shoot me a pm and I will give you my address for you to send me a self addressed stamped envelope to send it to you in.
Re: ....and it begins!!!!!!! (mcwire build)
December 16, 2008 04:07PM
Demented----- I do not have the skate bearings yet as I might be revising some of the designs. It will not be a problem getting them tho. Either from RRRF or one of the local 8 or so skate shops.

NewPerfection----- I will also be posting this on the main blog if I get accepted to it. I will be posting plenty of photos too. They will be high quality with good lighting as I am a professional photographer after all. I am sure that you might be able to save some $$ by going to a plumbing supply store and not a big box store like HD, ACE, or Lowes. What they charge for the pre cut pieces of 1" iron pipe I could have bought a 6' length for. I am sure a local plumbing supply would cut the pieces from scrap and not charge much. The big cost comes in with the 12" pieces and the flange. there is no way around the flange but if you could cut the 12" pieces from scrap you could save 8-12 bucks right there.

Funny story. I am back home for the holidays, thats part of the reason I went shopping for the stuff. All the stores I went to are within a few miles of each other rather than 30 miles apart like back at my home. Ok so I went into radioshack today to pickup a cheap soldering iron and a capacitor to fix a blown cap on my mothers home theater amp. While I was in there I overheard the 2 guys working their talking about a new 3d fax machine they are developing in Japan. Said they caught a segment on some show on Discovery or something. They said that the way it works is you put a 3D object onto a "scan bed" and it scans the object with lasers, then sends the info across the net to another 3D fax across the world. The receiving fax machine then prints the 3D object they scanned. The guys said that you had to put a refill spool of print material into the fax after a few prints (HDPE maybe?) Like it or not 3D printing is the way of the future.

I know that does not pertain to my Mcwire build what so ever but I thought it was interesting that their is work being done on a 3D printer that has the 0ossibility of scanning its broken part and creating a new one to replace it.

Edited 2 time(s). Last edit at 12/16/2008 04:15PM by SCphotog.
Re: ....and it begins!!!!!!! (mcwire build)
December 17, 2008 07:11PM
You scan a broken part...you then print it...now you have two broken parts! ;-)

Re: ....and it begins!!!!!!! (mcwire build)
December 17, 2008 07:16PM
Well you would have to write in some reconstruction algorithms that could match up the edges of the break and digitally reconstruct the broken part then print a new part.
Re: ....and it begins!!!!!!! (mcwire build)
December 18, 2008 04:27AM
glueing it physically is way easier than glueing it digitally grinning smiley

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