Will this fitting leak?

The item in the image seems to be just what I need (the brand is Lasco and the model number is 08-1089, "Bathcock Ell"). It attaches to a 3/4 inch male threaded pipe and, after a 90 degree bend, it has 1/2 inch male threads. However, I've never seen a fitting like the one on the 3/4 inch end of this. There are no directions provided, but the guy at the hardware store said to just screw them together, and if that doesn't work "apply some plumbers putty" (the latter comment did not inspire confidence). It seems to me like a rubber O-ring might make for a better and more reliably leak-free results (btw, I've found an O-ring that fits well). Any thoughts? Thanks.

Mark

fitting

That one looks like a 1/2" sink faucet tailpiece elbow. A 3/4" one would be for a leg bathtub faucet, but I have never seen a short one like that for them. usually they are long bent tubes with the nosepiece formed after a short bend. What are you trying to use it for. If used for its intended purpose you do not use an "O" ring, plumber's putty, or anything else.

clarification

It's for a bathtub faucet (freestanding) that'll be used with a clawfoot tub. A lack of space necessitates the short right angle.

So, this should work as is?

Thanks.

Mark

Like Hj said, the bathcock ell fitting is specifically made for clawfoot tub faucets. It is possible to make an adapter, but that would be ugly and bulky to use all the transition fittings, so a bathcock ell fitting is the best choice if you can get your hands on a pair! The faucet threads are normally 3/4" iron pipe thread, so wrapping them with teflon couldn't hurt. And you should be able to use a flex connector to connect to the 1/2" side of the bathcock ell fitting if that's how you choose to do it.

No Teflon tape.
The Teflon only causes problems.

Just slam it on.