Sanke diptube sight glass protector

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Aug 3, 2006
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Whitehouse Station, NJ
I've been talking about doing this and finally got around to mocking it up. The tube is the perfect diameter for fitting over a half inch compression nut with a little hammering.

The hard part is cutting a nice uniform slot down the tube. I don't know anyone with a mill so I tried a grinder and it came out OK but it's still too sloppy for my taste. If anyone has a mill and wouldn't mind helping me out, PM me.

This is basically what I have in mind:



1/2" or 5/8" wide slot right down the length...
You beat me to it, I have the tubes, sight glasses but havent found the hardware yet.
I don't know that a mill is going to make it look much prettier. They tend to chew up sheet metal. Just be careful with the grinder, and clean it up with a file and some sandpaper.
Yeah, I guess a mill won't help. I might try putting a metal cutting disc in the table saw but I'll have to figure a way to feed the tube in without killing myself.
Hell, I think that looks downright nice. If you really wanted to get funky with it, you could mark and cut notches for every gal/qt for keeping track of the volume. I went the cheap route and installed a plastic sight glass. I marked out every qt. Then I put two zip ties on the sight glass. They fit snug but still slide up or down. If I want to sparge 10 qts. I slide a zip tie to the current water level and one down to the level the water would be at minus the 10 qts and let er pun intended. It's an easy way to keep track of your water usage.
Yuri is probably right; a mill is hands-off but cutters like to push sheet metal, so the grinder idea is probably leaving the uncut portion in a better condition. Die grinder and burr bits and sand paper flapper will finish that up nice.

Tell me more about shaping the lower end to a hex- did you start with a smaller hex to preform the flats, or just turn it to three different 180's and tap it with a hammer, 60 degrees apart, each?

I second the hash marks with dremmel/die grinder-then highlight each hashmark with a paint pen to make them more readable. Sharpie or paint pen on the keg wall for the corresponding numbers.
Saw a site tube with the SS protector at Brewer's today, $70. It looked nice but kinda thin and short. I think the keg tube will not oly look better because of the size but wiil be more durable also.
I have a rather outlandish idea. Find a nice and thick carbide router bit, the kind used in circuit board shops, and attach it to a router. The kind you would use for woodworking. Then attach the router to a router table. Drill 2 holes, one on each end, the start hole and the end hole. rev up the router and drop the pipe into the start hole. Run it down, slowly, to the end hole. if you made a jig with a few pieces of wood to hold the tube I think it would work great! Maybe this outlandish idea will work. Hope my ideas at least spark an idea somewhere! :rockin:
I thought about using a V-groove carbide router bit but just as I was about to plunge the tube down (held to wood with some EMT hangers), I had a last minute "WTF am I doing".

I loaded an 8" thin cuttoff wheel into my tablesaw and made some test cuts... it's butter. I just have to clamp some stops and run the three tubes.

The hex is formed with a spare compression fitting and a hammer with a little oil for lubrication. It was the easiest part of the project and had four tubes done in 10 minutes.

Brewer's is getting $70 for an inferior version of my sight kits. Wow, I might have to increase my margin a bit.

Once I get the process dialed in, I could make up more for anyone that sends me their tubes and just charge a few bucks for my time.
Bobby_M said:
Once I get the process dialed in, I could make up more for anyone that sends me their tubes and just charge a few bucks for my time.

I have one of your site tubes, and will probably take you up on that offer once it becomes available.

I was just curious how the top of your site tube protector gets mounted. Your picture only shows the bottom.
I'm not there yet but I will probably extend the tube up a little higher than the glass and cut it on a 45 degree angle so the high side is closest to the keg. I'll then drill a small hole through both the tube and the keg's upper skirt. Then I can use a stainless bolt through and just use either nuts or washers to space it perfectly so that the glass is centered. I'll use Orings or grommets to hold the glass centered. More pics coming.
I made up this jig to hold the tubes while I ran them on my tablesaw but the freehand cut one actually came out better. I think it has something to do with wobble in the larger diameter discs. The 4" grinder is rock solid.


The one on the right was cut by hand.

I cut the top at about a 30 degree angle with the high side opposite the slot. I plan to drill a hole in the tube and then tap a hole in the keg for a 1/4-20 bolt. I'll then use washers to make up the gap between the tube and keg.


This project took a lot of time but piece of mind is pretty important to me.

I got some more questions about this DIY so linked to it in my sig and wanted to add some followup details.

I don't really know the inside diameter of these sanke dip tubes, but whatever it is, it is exactly the right size to be formed over a 1/2" compression fitting nut. While I currently like compression elbow fittings for the sight glasses, you'll need a straight version to use as a die to form the end of the tube. Apply some oil to the inside of the tube and outside of the compression nut and pound it in with a hammer. If your fitting is male NPT on the end you're hitting, a pipe cap can be threaded on to protect it. YOU MUST form this hex end before slotting the tube lengthwise.

In the installed position, the bottom of the tube is just pressure fit onto the nut of the sight glass fitting. At the top, it's secured to the keg with a 10/32 machine screw. I tapped the keg skirt so it would thread directly in but you could use a backing nut. I cut a piece of 3/16" ID thick wall beverage tubing as a spacer.

I had thought you were all done with this, Bobby.

I did this back a few months. I used another similar sized hex that I rounded the corners off a fair bit, for the first form. I alternately tapped the Sankey tube above each flat with a hammer, and smacked the tube down over the hex from the opposite end with a spiral wound leather mallet. When it was close to the correct shape, I then used an actual compression nut that I only slightly removed the hex corners on, to finish the hex shape in the SS tube.

I first made sure of correct tightness for each sight tube for each keg, and marked each tube for that keg. After getting the tubes to sit down to a uniform depth on all three keggles, I assigned each tube to a keggle, for the orientation of the slots for each keggle. I marked each tube for its correct direction outwards, so that the slot would appear correctly aligned, to the clocking of the hex flats for it's associated compression hex nut. I then just used nails driven part way into a wood bench to hold the tube. I put a set of nails on either side of the tube, a 1/4 of the length in from each end, and bent them inwards to hold the tube side to side, and put a nail at each end to keep it form sliding towards or away form me.

I used a heavy duty angle grinder and coarse stone-type wheel to coarse grind the tube to a Sharpie outline I had drawn when it was installed over the glass tube on the keg. When I had most of the stock removed, I then used a 5" air grinder with a 120 grit disk to shape the sides of the slot parallel and to size. I checked the width of the slot with a set of calipers to do the parallelism, but just eyed the straightness of the slot. The ends are formed to shallow out as to make an oval shape start at each end, rather than a square-ish shape as you have shown. A little work with an air die grinder to de-burr and fine finish the shape, and I was done.

I just inserted the next tube into the nails to start coarse grinding it. The SS tubes get VERY hot during grinding, and the removal is poor; it mostly bends under and must be ground away after getting thin, by the 5" disk grinder during the coarse grinding, then continuing with the angle grinder once again.

I cut the tubes to the length required by my placement of the SS eyebolt at the top of the upper skirt. I cut them off square with a thin cutoff (1/16") wheel on a die grinder, and after carefully de-burring everything with a burr knife ( a sharpened 3-corner-file type of deburring tool), and a fine round file.

I also used a set of o-rings from Corny posts to hold tube central to eye bolt, which had the effect of holding the SS tube central to the glass tube. The same o-rings were also used as a sort of compression ferule inside the 1/2"NPTx1/2"tube 90* compression fittings. I did not use the SS ferules that came with the fitting.

I take no credit for any of the concept, it was all Bobby's idea and I also got the glass tubes from Bobby. My contribution to this is my execution of the concept.
Bobby, using that jig you made, a band saw would be perfect for this. Just lay the jig on its side and slice off a piece of the edge.
Oh, I have been done with this project for a while but I was getting a bunch of questions about them from folks who hadn't seen the original thread.

Since then I spent a bit of time inquiring about getting these protector tubes mass produced but I have yet to encounter a metal fab or even tubing specialty company to admit to the ability to create a clean slot.
I never saw this before/ Great solution to protecting the sight glass. I saved my dip tubes from my kegs cause i knew they'd come in handy somewhere!
The great thing is that they are basically surplus scrap and if you screw up the slot cutting, you're no worse off. This isn't something I would go through for a polycarbonate tubing based sight glass but it's absolutely mandatory for those using pyrex glass.
I just fabricated mine tonight. Not a dip tube, but another piece of thin tubing I had laying around.

My thoughts on the target level markers (zip ties) was to grab a few 1/2" od ORings and have them available for marking targets. Now if I could only find singles in different colors, that would be cool. I think I'm going to paint the inside of the tube and just mark on the back the quart levels...Now I need to figure out what color. It'll be my HLT, so I'm trying to make water more visible...
Could you use a black permenant marker to mark the lines on the back of the tube and then paint over them with white paint? That way, you should be able to see black on white contrast.
Have you thought about either drilling a small hole or slot in the back of the shield at the gallon marks. Shouldn't the light show through?
Followed what bobby did using a 4" angle grinder a dremel and white high temp are the results!
My sight glass is currently poly, but I've been thinking about something like this for a future glass upgrade. Rather than starting with a tube, my idea was to start with a flat sheet, then bend it into a C-channel shape and weld directly to the eye bolt at the top. I hadn't decided how to mount at the bottom, but a similar method should work. I don't think you'd want to weld directly to the fitting nut on the bottom, but could weld to a SS washer that would then fit between the fitting and nut. It seems like this would be less work and you'd have those nice clean edges.

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