hole saw conversions

[chef19872002]

Evening fellow reefers have a question I am about to drill my first tank and need some help here converting the bulkhead size to the diamond hole saw in mm?
If anyone can give me the mm conversion on a 3/4" bulkhead a 1/2" bulkhead a 1" bulkhead a 11/2" bulkhead and a 2"' bulkhead. I need the sizes in mm so I can order those hole saws for my tank I would appreciate the help Thanks Tom

 

[jeremygreen]

It kind of depends on the hole saws. Some of the heavy duty ones need larger holes.
Marine depot has the hole sizes for the bulkheads that they sell (in inches):
http://www.marinedepot.com/aquarium_plumbing_parts_fittings_bulkheads_strainers.asp

So, a 3/4" heavy duty bulkhead needs a 1 5/8" hole according to marine depot.
You can use google to convert for you just search for "1 5/8 inches in mm" and it answers: 41.275 mm

The bulkheads have a good bit of leeway because the gaskets have a pretty big seating area.
The best thing to do is probably just use a tape to measure your bulkheads (if you have them already) and convert that to mm with google (or by multiplying it by 25.4) and get the next largest size hole saw (assuming it's not drastically bigger).
I bought a bunch of hole saws from this guy: http://stores.ebay.com/Treasure-HK-Ltd

They aren't the highest quality but they will work to drill a few holes. I got an 80mm one from him that I used to drill a hole for a heavy duty 2" bulkhead. I had to rock the hole saw around a little to make the hole a tiny bit bigger to fit the bulkhead.
You can't beat the price...

-Jeremy

 

[FuzzyLogic]

<a href=showthread.php?s=&postid=6692905#post6692905 target=_blank>Originally posted</a> by jeremygreen
They aren't the highest quality but they will work to drill a few holes. I got an 80mm one from him that I used to drill a hole for a heavy duty 2" bulkhead. I had to rock the hole saw around a little to make the hole a tiny bit bigger to fit the bulkhead.
You can't beat the price...

-Jeremy

How many holes were you able to drill with these? I have 1/2" glass and need to drill 4 holes.

 

[jeremygreen]

I have done two holes with the 80 mm one. It looks like it would do a few more. After the first hole it felt a little less coarse but the second hole drilled fine. It still has some bite two it. The second hole actually came out nicer than the first. Both of the holes were through 3/8" glass with a good bit of soapy water for lubrication/cooling.
It seems like at the price you could buy 2 of them and still come out ahead...
You do get what you pay for but, most people don't need $100 hole saws since they will only drill a few holes with them.

-Jeremy