how to adjust Ajax H-H worm play?

**B.J.** · 08-24-2010 02:54 PM

My 10' Orbitron is on an Ajax H-H. This drive has developed quite a bit of slop, which I assume must be in the worm drive. Before I waste a lot of time trying to fix this, I thought I'd ask whether anyone here knows how to get rid of this free play?
There are 2 big bolts holding the motor/worm drive to the mount, and it looks like *IF* the holes are oversized a bit, that if I'd loosen these bolts, then I might be able to push the whole assembly up closer to the big semi-circular gear, thus taking up the free play. On the other hand, if the holes that the bolts go through are tight fitting, then I wouldn't be able to move the assembly.
What I was HOPING was that maybe one of the holes is tight fitting, and the other one might be elliptical, so that it might swing up rather than having to lift both sides.
I'd just take the nut off, and look, except that I'm afraid if I do that, that the thing might drop down, then the gears will let loose, let go, and the whole dish might come flying down. So first I have to figure out a way of locking the dish at the top of it's arc while I'm working on it.
Anyway, just curious if anyone has done this before. Too bad I didn't take pictures of this thing when I put it together about 14 years ago. Seems like somewhere I have the assembly instructions, but I don't think they were in much detail at all.

**mick d** · 08-24-2010 05:08 PM

Wish I could help you with the actuator but as far as the dish, What I do is position dish where ya want it then tighten the bolts at your hinge if you have the ability to do so, then take your actuator loose.

**FaT Air** · 08-24-2010 06:05 PM

I'd run it down one way, attach a rope/cable to the side thats low, then run it to the other side, past center, and then attach rope to an anchor, take up slack and have hat it. this way the dish is pulling on the rope, and shouldn't go anywhere while working on it. Ive done this in the past on BV H to H mounts.

**madbull** · 08-24-2010 06:43 PM

B J, I think you will everything about the Ajax h-h in this thread. May have to read the entire thread to find it. But there's a weath of information there. It was a big help to me. Hope this helps.

http://www.satelliteguys.us/c-band-s...jak-mount.html

**1captain** · 08-25-2010 06:12 AM

morning Bill.

yes the 2 big bolts are how you will set the play with the worm gear and 1/2 moon gear. the bolts are 1/2" fine tread and are taped into the motor bracket, most of the time they have some kind of epoxy over the head of the bolt to stop them from becoming louse, so that will need to be removed if it has not been already scrap off. both holes are egg shaped and the motor bracket need to move evenly up to the 1/2-moon gear. by all means do NOT swing it or tilt it to the 1/2-moon gear. now you should also see a bunch of shims behind the motor mount and the main bracket, if for some reason you want to remove the motor bracket make note on which bunch of shims go to each of their locations, and remember to block the dish up if you remove the motor bracket.

one thing that also can cause this and the problems that you are having. is the tube that the 1/2moon gear is welded to, it is about 3/32" smaller than the tube it rides in where the zerk fitting is at. and what Ajak did to take up this play they put shims of plastic in and around this tube (on the inside) strips too. and in time I have seen them crack and break up to where they will cause a major bind in the dishes rotation. had a customer that this happen to, and he snaped the end right off the motor that drives the small gear on the chain. the only repair for this is the dish has to come off the Ajak mount.

if I was having this problem of the dish having a hard time come up from a low satellite, what I would do is remove the motor bracket (motor, chain and worm gear) an have some one holding the dish when it is being removed. now the dish should move freely up an down then by hand move the dish threw its ark to see if their is any bind in the mount, and if their is you may want to run a lot of grease in the zerk fitting and keep working it by hand to try to free it up.

good luck Bill, check you're pm box.

**B.J.** · 08-25-2010 07:04 AM

Thanks all.
The egg shaped holes is what I was hoping to hear.
I think that if I can support the dish temporarily, I will take the motor/worm gear assembly completely off, because it has been hard to get grease in there, and it hasn't had a proper grease job for years. I'm not sure how or why, but it seems like mice or chipmunks like to build nests inside the plastic housing, and the sticks jam the gears too.
Back when I used an actuator on another dish, it was easy to support the dish, just using a short length of chain, sort of replacing the actuator, but this darn dish swings high above the rotation axis, and since I also have the darn spinclination type dish, it isn't really good to support it via a point on the dish itself, but will probably have to somehow block the movement of the mount itself.
I used to have a big metal bar bolted onto the mount, to which I connected a big log as a counter-weight on a chain also connected to a nearby flexible pine tree limb, both of which gave me a bit of pull to help the motor pull the thing up from it's low point. Perhaps I could put that back on, and run a tight chain to a tree to hold the dish up.
I'm really wishing that I had bought an actuator mount instead of this thing. When I first got it, I wanted the H-H because I had visions of seeing all the sats over the atlantic, and initially I had LOS from 135W thru somewhere around 20W, but now the trees have grown so much that I can only see from ~125 to ~50W, and I could do that with an actuator, and an actuator would have been MUCH easier to service, and is much better for getting the dish down and back from near the horizon. Ie actuators have best mechanical advantage near horizon and have problems near flop point, while H-H have problems down low near horizon, and are fine high in the arc.

**Anole** · 08-25-2010 12:30 PM

Originally Posted by B.J.

... Ie actuators have best mechanical advantage near horizon [1] and have problems near flop point [2], while H-H have problems down low near horizon[3], and are fine high in the arc [4].

I hope I haven't taken this out of context.
But of the four claims, I take issue with several. -

**B.J.** · 08-25-2010 01:22 PM

Originally Posted by Anole

I hope I haven't taken this out of context.
But of the four claims, I take issue with several. -

? Which do you take issue with? Unless there is some mis-communication due to poor wording on my part, re to what I was saying, I was pretty sure that all 4 should be non-controversial?

Ie
(1) For an actuator, near the horizon, the mechanical advantage I was referring to is that the actuator is more in line with the motion it is creating, whereas the higher it gets, the motion created is more perpindicular to the extension of the actuator, so near the horizon a higher percentage of the actuator's force goes into moving the dish. Yes, there is more weight to lift near the horizon, but the mechanical advantage is greater down there. Said another way high in the arc, a small actuator movement generates a greater angular motion, so it's like a big gear moving a small gear, ie more speed but less mechanical advantage.
(2) Actuators are known to even self destruct once you get past the flop point too much, because it takes an incredible amount of force to pull the dish back, because only a fraction of the force goes in the direction of the motion. Of course this is highly dependent on the design of where the connection points are, but I've read many posts from people who went past the flop point, and the actuator basically pulled the guts out of the tube and the dish flopped over to the ground. I had an old SAMI dish, where the actuator attached fairly far out on the dish, and you get past a point where the actuator actually would bump into the side of the dish and dent it, and it would have had to rip the dish apart to pull the dish back. I had to go out and move the dish by hand to get it back.
(3) & (4) Down near the horizon, a H-H is lifting the full weight of the dish, usually extended out past the rotation axis, which requires a LOT of force for the motor to lift it. At the top of the arc, the motor doesn't have to lift ANY of the dish's weight, so it doesn't have any problem up there. I've never had any problems with my H-H moving a dish when it's high in the arc, but I've gotten stuck hundreds of times when low near the horizon. The actual mechanical advantage of the H-H should be constant everwhere, but there is more weight to lift when low. Sort of like sticking a bowling ball on a broom stick, and pointing it straight up, you don't have any problems supporting it or moving it, however if you hold the stick out horizontal, it would be extremely hard to lift since you have the lift the entire weight of the ball.

Anyway, that's what I was referring to. I assume that my comments came across as saying something else?

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