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DIY Projector Build

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- 26 July 2008 -

Ok, so I know I promised design ideas and I plan to give you just that, but first a little work I got started on over the weekend. . . .

At the forefront of my mental list of issues needing attention was what I was going to use for a focusing mechanism. After spending several hours at Home Depot and Lowes I was able to come up with a plan that might just work. Basically I just took my Pro Triplet lens to Home Depot with me and found a piece that fit as closely around the lens as possible. The piece I ended up getting had a slightly larger diameter than the flange on the pro triplet which will work out perfectly. While I had the Home Depot guy trying to help me find something I asked if they get a lot of wierd ass requests for weird ass projects. Apparently they call the PVC aisle at Home Depot the "Macgyver Aisle". : ) Seems pretty accurate to me! Well, I couldn't quite find what I wanted at Home Depot so I went over to Lowe's and was able to find something that I think will workout well. Here's the part numbers of what I got in case any one else thinks this is a good idea.

4"x4" PVC SOILPIP 23323
4" DWV x S&D ADAP 171362
Knobs Clamping #1 139655
T-Nuts, Three Hole #10-32x 137336
.085 8x10 Clear 72055

That last item is the UV coated Lexan. And above that is the knob and blind nut or T-nut, whatever you want to call it, that I will use for focus adjust. Ok, on with the Macgyvering! First up is what will become the inner ring that holds the triplet. I will actually be using the larger half o fthis adaptor. The Pro triplet is huge!

Cost of PVC and hardware: $25 - Lowe's

Let me just say here and now, cutting PVC sucks! When cutting perpendicular to the surface it's not bad, in fact, it's like butta. However, cut parralel to the surface sucks. Here's a few reasons why: First, your cutting area is ten times bigger, this slows down the cutting. Second, with this much surface area friction is increased, this increases heat meaning you have to stop periodically to let the piece cool. Third, increased heat means the PVC likes to get sticky, it doesn't exactly melt, just gets "tractioney" and likes to grab a hold of the blade. Fourth, cutting round pieces are extra sucky because once heated up and getting all "tractioney" they tend to just weeble and wobble back and forth with the blade. I ended up using some Windex to try and lubricate the blade to help keep it from binding. But, once it was all said and done this is waht I ended up with.

Not exactly a clean cut, I know. So, out with my brand new file set and a little cleaning up of the edge was done.

Once I had finished with the rough clean up I took it out to the garage for a finer sanding....on the floor. Hey when you need a large flat surface a table is good and a poured concrete floor ain't a bad second best.

Once I got that half way decent it was time to turn my attention to the other piece, the outside tube that the triplet would ride inside. Again, with more cutting parralel to the face, yay!

After finishing the cut it still took considerable amounts of filing to get the slot wide enough for the knob.

Once I had the filing done the knob was able to move the full distance without binding up.

Originally I planned on cutting out a section on the piece that wraps around the triplet but that would have left the flange on the triplet sticking out, so instead I decided to shim the excess keeping the triplet centered , like this.

I picked up a length of peel and stick Velcro today and that's what I'm planning on using to shim out the gap. Finally, I started the slow and tedious chore of removing material from the inside if the larger piece so that the triplet and it's new PVC sleeve will slide right in. Another slow and tedious process, but it's made a liitle easier with a bench drill press and a new drum sander kit. I found that if I just kept the piece flat against the table and pressed the side against the drum sander the drill press would sand and turn the piece with little effort from me, bonus! This is at about a third of the way done.

Ok, so that's it for now. I know, not much of an update but I am hoping to pick up the pace on this in the coming weeks. My plan was to have it up and throwing a picture by the end of July. July is gone now, I don't know where it went........ : (

 

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