absplumbing
I would like to cut an existing pipe and install a coupler to connect 2 pieces of 3 inch ABS. I would like to make the connection where I am pointing on the image.
Is that enough pipe to connect to (approx 0.5 inch)? I would like to avoid going back to the main if possible.
You can get a flange that fits inside a 4" pipe, or if you remove inside get one that sits inside a 4" hub.
They make fittings that we call "Moody Couplings"; this may be a regional or colloquial term but probably evolved from a manufacturer's name.
These are designed for pressure pipe, the size designed for 1/2" galvanized pipe also fits 3/4" copper. These are not designed to be installed in locations where a leak would not be evident/fixable, and they do require a relatively smooth outside surface (but are a bit forgiving in that respect). If you do this, I recommend not covering it up, so you can monitor.
Best Answer
No, it is not. If you read the manufacturers' instruction on the ABS cement it says to seat the pipe completely in the hub.
Now... I have cheated the above instruction on more than one occasion but never to that extent. If you are careful, gluing to 1/2" of pipe will probably not leak immediately. The problem is that the strength of the joint will be compromised and any movement (due to soil movement, expansion/contraction of pipe with temp changes, etc.) could cause failure.
I say you should "bite the bullet" and cut back to the next available spot where you have some pipe to work with. You will likely have to rebuild that whole junction area.