Here's a hypothetical: Let's say I have to build something similar to the following picture, and I'm looking for ways to attach the square spindles between the rails.

Attachment 254189

I circled the joints in question in red but it's hard to see unless you look closely.

In this completely hypothetical situation, a deadline is fast approaching and my PM701 mortiser just broke. For the sake of completeness we'll say that the splines in the handle hub wore off, and the machine is totally unusable until the replacement part arrives by slow boat from the far east, which will be well after the project deadline.

Given that the most obvious and well suited tool is now off the table, what's my next best option for attaching the square spindles?

The spindles will only be 3/4" x 3/4" so I don't think I could effectively use my dowelmax or kreg. The dowelmax would be hard to clamp consistently and hold the pieces in place while drilling, and I've had kreg screws crack the wood on 3/4" x 3/4" stock too many times to try it again.

Here are a few constraints: I would really like to not have to do them by hand, I can't move the deadline, and I am looking for a solution that would be considered professional by other woodworkers and/or clients.

Is there a reliable/simple/safe way of trimming a round tenon with a flat shoulder on the end of a square stick? If there is, I could just use drilled holes for the mortises.

Is there another solution that is appropriate here?

Thanks,
Andy