Making a probe holder...

[xcaret]

I'm thinking of making a probe holder, will borrow a drill press from a friend but would like to know the diameter of the hole to be drilled for the probe to fit snugly; also want to add some threaded push connect/JG fittings there to have the 2/3 part dosing system; what would be the drill bit diameter to fit a threaded JG fitting? I'm thinking the 1/4".
I'm converting an old 40G plexi into a sump/fuge.
On the image, the chamber to the right is the slow flow fuge and the plexi bar at the bottom is the one I intent to drill for probes and dossers.

Thx

 

[houser]

xcaret,
I drilled a 3/8 hole for 1/4" tube fitting then screwed it in since I didn't have the the right tap. So more destroyed the threads than anything else, but it is not going anywhere. For your pro setup tap it
And used plastic drill bits too.

 

[xcaret]

Thx !

I've been looking for those fittings at home to measure diameter but no luck finding them; I'm sure I'll find those when I'm not looking for them.

 

[konkers]

I drilled my probe holder for a snug fit (can't remember the size) but wish I'd oversized. The 2 other probes that I've tried have been slightly larger than the first and they tend to bind in the holes.

If I were to do it again, I would go with a design like http://www.nicksreef.com/images/diy/probe%20holder.JPG .

Also, it's worth noting that all the probes' directions say they should be 6" apart from each other to avoid interference.

Cheers,
Erik

 

[GreshamH]

1/4" NPT IIRC for the JG fitting (for RODI tubing). Will check in a few minutes, I have one laying around in my workshop.

 

[houser]

x-
I used this from Mcmaster carr
5016K411
tube fitting
this was 1/8"NPT
tapping for 1/4" NPT IMO means you've got to really pick the right size bit. Well you should do that anyway!

 

[GreshamH]

Since I normally get tapered NPT taps that drill bit size is essential. Just grab an online tap:bit guide.



example:
http://icrank.com/cgi-bin/pageman/pageout.cgi?path=/chart_npt.htm&t=2

http://www.carbidedepot.com/formulas-tap-pipe.htm

winners:

http://bobmay.astronomy.net/misc/drillchart.htm

http://www.imperialinc.com/pdf/I_Tap&DieChart.pdf

 

[xcaret]

Thx now to get a cheap tap/die set; the only tap I have is 3/4 NPT !!
Where are the nice sidewalk sales? I'm sure I spotted a few tap/die sets last year but had no interest in such things then.

I broke too one of the fittings on an old KnopC CaRx yesterday so might as well do some DIY fixing on it, sort of "screwing around"

 

[xcaret]

x-
I used this from Mcmaster carr
5016K411
tube fitting
this was 1/8"NPT
tapping for 1/4" NPT IMO means you've got to really pick the right size bit. Well you should do that anyway!

That's the little part I broke off the reactor!! but I think I'll replace it with push connect/JG

 

[GreshamH]

Harbor Freight has cheap Tap/dye sets. You get what you pay for but they do get you out of jams.