I was looking at a pack someone was selling today and something about the ribbon cable struck me as being off.
At first I thought they might have used the ribbon cable being sold in the GBFans shop, as the clamp he’s using appears to be from there, (It fits the cyclotron ring snugly.) and I wrongly remembered that cable as being narrower than the real one. (It’s actually a bit wider.)
But after some investigation, I determined that he is in fact using the correct 30 pair cable, and the problem is actually with the clamp itself being too wide.
To be sure, I took my own 30 pair ribbon cable and placed it inside the cable clamp I purchased from the shop, and sure enough, it’s a match for the pack on sale, but it doesn’t match what we see in the reference pics. The easiest way to tell there’s a difference is by looking at the bolts. On the GBFans clamp, a 30 pair cable just about fits between the bolts. But on the real packs, the bolts actually overlap the cable significantly. The end result is that the clamp appears to be something like a quarter of an inch too wide on each end.
Of course appearances can be deceiving. It’s possible the clamp is exactly the right width, but for some reason, even though the cable has the correct number of wires, it’s still narrower than the cables produced during the 1980’s were. But that would be much more difficult to determine.
The GBFans clamp is still the most accurate clamp available in my opinion, and you could always take a hacksaw to it to narrow it down a bit, though nothing can really be done about the locaton of the bolts as they come pre-drilled. But I thought I should point this difference out so that maybe on the next run the design could be altered if neccessary. Perhaps he made it wider than normal intentionally though… seeing as the ribbon cable he sells is a bit wider than the real ones. Which I guess would make sense, but it would be nice to have a clamp sized for the 30 pair cable.
If you have a newer one of my clamps, it should be right on. I measured and proportioned it out using photos and it came out closer to the real deal. Stefans plans show the thing as being huge.. and we all know that it is now too big.
Yeah, I think Stefan’s plans showed the clamp to be 4" wide when an accurate clamp is 3.5" (going from memory here). There was a discussion (argument) about it on Proptopia a couple years ago now (I think).
My clamp is 4" wide with the bolt holes being 3" on center, the ribbon cable is 3" wide so the bolt holes overlap the cable by 1/8" on either side. I’m sorry but at 3.5" wide the bolt heads would almost be touching the edge of the clamp and just doesn’t look right..
The old thread on Proptopia is gone now I believe, but here are the images I created at the time showing the comparison of a 4" clamp and a 3.5" clamp. The ribbon cable itself can be used as a measuring tool. You can see that a 4" clamp is far too wide. Obviously the one screw is not as far in from the right edge as the one on the pack.
When you say “your clamp” are you addressing me? The one in that pic isn’t one of the few clamps I sold. Anyway, in that pic I’d guess that the cyclotron is someone’s cake pan version which most likely means it’s far too small.
I took the reference pic irricanian posted above, and using an app I happen to sell which is designed specifically for this purpouse, I removed the perspective from the image. I then imported the image into photoshop, and scaled it so that the ribbon cable was 3" wide when the image is displayed at 150 dpi.
The resulting image, seen here, is 3.65" wide. Which is notably less than 3 11/16", but slightly more than 3 5/8".
I think it’s safe to round it down to 3 5/8". (3.625")
All of this assumes of course that the ribbon cable is 3" wide in the photos. But there’s no guarantee of that.
I had to of come to that conclusion from some measuring off of pictures though. Understand that ALL of these are going to be different from pack to pack as they were cut by hand. So I must of taken measurments off of the photographs and perceived them as 4".
The other thing to consider is whether it be a fiberglass shell or a scratchbuilt pack there may be differences on the cyclotrons radius for fit. One thing for sure is the 3" on center bolt pattern so that the ribbon cable looks correctly placed.
I wouldn’t be too worried about the difference in length 4" or 3 5/8" , if its that big of a deal just take off the 3/16" from each side with some tin snips or cutoff wheel. It’s really not a big deal.
At 3.625" it’s much closer to 3.5" than to 4". As I am sure I stated in the thread back on Proptopia, the 4" clamp is visually just too wide and makes it look like the cable is tiny. Not bashing anyone’s work, but in my opinion the 1/2" to 3/8" is a big difference.
The sections with the twisted pairs is a tiny bit under 3". Unfortunately without a straight on shot scaling isn’t going to be 100%. Unless some better pics surface we can’t definitively say, the absolute measurement though I tend to agree that something around 3.625" does work visually. My complaint with Stefan’s 4" clamp is that it doesn’t look right with the cable.
i have some newer production 64-pair spectra strip cable that if two pairs are removed measures 2" 15/16". so 3" is pretty close to the right size for the cable.
Yeah I agree that variations could easily exist in width especially considering they were pretty quickly cut on a band saw (at least partially).
Oh also, I wasn’t paying attention closely enough to your photo, the straight pair section of the cable (which is where the clamp is on your pic) is a bit more than 3" wide. This would only affect the scaling a small amount. The pic you used as reference is at a good scaling reference and the numbers would appear to come out to something around 3.5625" and 3.625" for the clamp on the stunt pack at Sony (I forgot about the Sony pack pics I haven’t revisited the clamp since those pics came out), it seems pretty consistent with the PH Minnesota hero pack as well. When I get around to making a clamp for myself I’ll most likely use 3.625" and probably more thoroughly go over any new reference available.
