Delta Contractors Saw - Need Help

[Tony Bilello]

I have a Delta Contractors Saw.
When I crank the handle to raise and lower the blade in normal operation, there is no problem. But when I want to make Dados, the height adjustment is critical and the blade changes height all by itself regardless of how hard I tighten up the knob.
If I remove the blade insert and look down there (with power cord unplugged) I could see a nut on the backside of the height adjustment.
This nut is on the threaded part that makes contact with the worm gear. While cranking the height adjustment knob, the nut stays put MOST of the time. But then at a certain point, the nut starts spinning and in effect loosens the height adjustment nut.
If you own the contractors saw, you know exactly what I am talking about.
I'm sure there is a quick fix for this problem, so what am I overlooking?

Thanks in advance

Tony B

[Ed Gerken]

Add a second nut and lock 'em tightly together or try a little locktite on the threads. Crank past where you want and then back it up, that will take the slack out before you begin to cut.

-Ed

[Doug Shepard]

I have no experience with that particular saw but I have noticed on several different saws a tendency to drop a bit if the height was adjusted downward before locking the knob. In other words you always need to raise the blade to the right height on those saws for it to stay where you lock it.

[John Jendro]

It's what is call backlash from the treads. I second the raise to the right height, don't lower.

[Tony Bilello]

This is the same nut that sometimes spins into a bad spot and the blade dont lower all of the way. I would think that there would be some way to retain this nut and keep it in the same position. I looked and cant figure it out.
I'll try to find the assembly drawing and find the correct name for this nut and call Delta. Surely they can help. Maybe?

Tony B

[Norman Pyles]

If you don't want it to spin, you could use a lock nut with the plastic insert. Also if your saw is one of the newer Chinese saw, it probably uses a metric nut.

[Tony Bilello]

The adjustment handle runs from outside the saw (cranking handle) into the cabinet on a threaded section. This nut is on the threaded section, If I use locktite or nylon locking inserts, the nut, being on the threads, will ALWAYS turn. Something should prevent this nut from turning while the threaded rod is turning inside of it. I cant explain without the assembly drawings because I dont know the names of these parts.

Tony B