Enlarging bulkhead hole

[Doug]

Can you enlarge a 1 1/8th drilled hole to 1 3/4, so they can take a 1in bulkheads?

I cant even get a 3/4in bulkhead in there, as I planned on. Even that takes a 1 1/2 in or 1 7/16in. hole. Only other option is to go with 1/2in and then enlarge stacks to 1in. but still a 1/2 in drain. I would then have two 1/2in drains and a 1in main drain for my bean

[sphelps]

It can be done by drilling another hole around it but unlikely anyone would attempt it. Better just to work with what you have, I'd use the two 1/2" lines for the primary and secondary and the 1" as the back up. I'd also up the line size before and after the bulkhead to 1" like you mentioned, 1/2" bulkhead with 1" line will flow a decent amount, much more than 1/2" line throughout and not much less than a full 1".

[LoJack]

Definitely risky to drill around it. I would do it if it was a brand new bit, and I'd be the most patient man on the planet … but still no guarantee's

Can you fit any sort of plug into it? I have a tank that was drilled once and I didn't need to use a sump anymore, so I inserted plugs into the threaded bulkheads with teflon tape so that I could just use it as a regular tank.

If this is an option, I'd consider plugging those off and drilling new holes where you want them. Not ideal, but probably less risk of crackle/breakage going that way. Assuming the original bulkheads don't leak I suppose.

[monocus]

make yourself a jig for the new hole so your drill doesn't move around using 1/4 " plywood.be patient and go slowly.

[Doug]

Thanks for the great advice guys. I decided that if I need a new bit anyways, to order a 1.75 bit for a new 1in. bulkhead in the back. I also ordered a pair of 1/2 in. bulkheads for the two bottom holes. One will be brought up to a 1 in. stack and drain line as per Steves suggestion. The other to 3/4 in. for my return line.

Sounds good, as long as the second hole drilling goes good. At least this time I will be using a new bit.

[Evilweevil]

Just go to princess auto they drill fine and go with the plywood jig like mono us said go slow and don't use a lot of pressure it will drill fine

[Doug]

Just go to princess auto they drill fine and go with the plywood jig like mono us said go slow and don't use a lot of pressure it will drill fine


Thanks. I was thinking, since getting the right bit, instead of drilling new hole in the back I may just try widen the smaller ones, with the wooden jig idea.



BUT


what if bottom is tempered.......:faint:

[Maverick00]

+1 on the wooden jig, i made mine out of a 2x4 with a "water inlet" on the top of the hole and "water outlet on the bottom of the hole using a file. You have 5/16" to work with per side which should be plently as long as you go slow and keep the drill as straight as possible clearing the glass "dust" from time to time.

Lots of info on the net on how to test for tempered glass, I thought it had to do with looking at the glass with polarized sunglasses with a smartphone screen illuminated on the other side. I personally wouldnt touch tempered glass.

[Evilweevil]

Does it already have holes in the bottom ? It's probably not tempered if it does but this is just a guess

[Doug]

Yes it does and you,re most likely correct. I have read where they drill the glass first then temper it however. :lol: Now that would be my luck.

[Doug]

I think best to error on safe side. I will drill another 1 in. as planned on rear, giving me the 4 holes. Im going to drill it a bit more to the open side of the tank and not closer to the side glass. I will just enlarge my overflow to 1ft. Takes away more tank but I will have a duzer of an over flow and herbie/beanie thing or whatever its called. :mrgreen:

[StirCrazy]

you could do it fairly easy, just need one of these, and yours drill bits have to fit it.

http://www.leevalley.com/en/wood/page.aspx?p=52518&cat=1,180,42316

most diamond hole saws have built in shafts though so might not work.

other option is to just drill around it, if you start on an angle and then shift to flat it shouldn't be to difficult, just use less pressure than normal and take your time. other wise get a new chunk of glass and redrill it, (this is on your overflow is it not) would be cheep for a small chunk of glass.

Steve

[Doug]

Im pretty sure just going to drill another 1 in hole in the back Steve. That will give me 4 as above. I ordered a larger overflow glass. Its now 12 in by 6in and 17.5 H not including eggcrate

[Doug]

Its a loss of space for the larger overflow but the safest way to go. And with the 4 I can do a 3/4in. return through one of the smaller bottom holes.

So a 1in. main full drain line...........a 1in. air intake 2nd drain line..........a 1in. but bumped up from a 1/2in. bulkhead, safety drain......and a 1/2in. bulkhead bumped to 3/4in. return line which is a perfect for for my Mag 12