Meade #1422 Low Latitude balance weight thumb screw question

[adder001]

Hi Folks,

Bit of a long shot here but does anyone know what the specifications of the weight adjustment thumb screw on the Meade #1422 Counter balance weight such as the thread diameter and pitch etc.

I have a 1.7kg orion starmax 90 mounted on a skywatcher EQ2 mount which was originally designed for the 130 reflector telescope and as such the counter weight was way to heavy for my telescope which weighs only 1.7kg. I am currently using the mount with no counterweight as the scope is so light.

I bought this meade weight off astroboot nice and cheap and it is 1kg which will do as I can put it on the end of the shaft to balance the scope but the screw is just slightly too short to meet the shaft so I need to purchase a longer one but I am unsure of the dimensions. 

It looks like an M6 thread but it maybe an american spec and I am not too familiar with that, also the pitch of the thread looks quite large.

Hopefully someone will know the answer.

Thanks in advance

[michael8554]

Imperial equivalent to M6 is 1/4" - 20 UNC  or 1/4" - 28 UNF

That's either 20 Teeth Per Inch or 28 TPI, you should be able to guess which with a ruler on your current screw

Michael

[adder001]

I think you might be right on the 20 teeth per inch, I have roughly looked at it against my ruler and it seems to be that. It is very hard to be precise this way though.

Cheers

[michael8554]

The coarser thread would be logical for securing a heavy object, many of the bigger Meade screws are UNC.

Michael

[adder001]

Thanks for your replies. I have ordered a 1/4 20 bolt 1-1/2" long. lt only cost £1.20 so its not too much of a risk but looking at the threads and the diameter and also what has been said it all seems to add up. Thanks again