Prather Pitch Gauge
 

Please see my listing.

http://www.ebay.com/itm/141116239987...84.m1555.l2649

Thanks, D

Really Dave? thought we were better than this:p

Better than what? Helping someone else out that can use this now that I am done with it?

I was just hoping to get it in the "Brother-in-law" deal instead of hand to hand combat on ebay. :)

Ahhh... I get you now... Well, that I understand, but I'm trying to maxamize my $'s..... Could really use some extra cash for Xmas and maybe a trip... Just selling off a few odds and ends that appear to be highly coveted at the moment..

and not to be mean, but I really hope there is LOTS of "hand to hand" fighting over there, lol...

Dave,

How much for a PDF copy of the instructions??

Trey

Dave people are willing to pay real money for old stuff ???? I have one here somewhere in my "Hobby " stuff I'll have to look for it
I didn't know you could get $$$$ for old stuff haven't used it since we quit Quarter midget WOW

Some are I guess Al... One of these sold on EBAY for over $100 recently... I guess some of the Control Line guys still use them, and some still use them for Q40 props... I just take em out of the bag and go...

Trey, I'll do my best to scan these in the next day or so. PM me your email.

D

Add me to that too Dave, a copy of the instructions. I think you already have my email address.

I founed it !!! A little dusty but still usable

Mines up to $177.00 Al, with several days to go... Better get yours listed :)

Actually, make that $280 now, wow...

A $1.29 and a bit of trig will get just as good an angle.

yeah, but if you're SELLING the pitch gauge, 280 is pretty darned good! :)

I still have one that I think is NIB, might hang on to it a while longer.. it seems they must be made of unobtanium.

I always thought the Prather must have found the design from overseas. The bed is metric (centimeter spacing) while the gage is in 3 grains of barley.

So what would a guy use to measure pitch while trying to mod up a prop to a 13x15 or maybe a 12x16?

Shawn,

You can make a very good pitch gauge for not too much cash with a protractor. The Prather gauge was not all that accurate, as you could skew the measurements by a number of ways.

To build a prop gauge, I would start with a good digital protractor like this General Tool model for $30.

http://www.generaltools.com/1702--DI...OR_p_1245.html#

Next you need a measurement board. Use a flat sheet of aluminum, about 1/4" thick or maybe slightly thicker plastic that is a bit longer than the largest prop you want to measure and maybe 4 to 6 inches wide (It will need to be pretty wide to measure flatter angles at the tips of props).

Drill and tap on one end for the different stud sizes of the props you want to use. Might be three or more sizes, but if you run out of room on one end you can also use the other end too.

Finally mill or cut slots through the board for the protractor arm to go through the base at the spacing you want to measure. As I said before, the Prather unit's station spacing was in cm, so if you want a direct comparison to a Prather, go with that.

To use, mount the prop using a short thread or bolt to the base. Insert protractor from the other side and take a measurement. Do the math to find out the inches of pitch at that station.

If you find out that one blade is higher or lower than the other, don't change the blade, change the hub. If the front and the back of the prop hub is not exactly parallel, then it's a good chance that blades won't track in pitch. You can scrap the rear of the hub with a single edge razor blade to get them right with each other. Then go ahead to change each blade as desired.

Thanks Bob, pretty much what I was thinking. The thing that I didn't think about was adjusting the hub. The goal is to see how small a dia I will have to go to get a YS 115 to spin a 15 or 16 inch pitch prop at 10k. Then decide if the airplane is clean enough to use the prop. I need to end up with an airplane that is close to 190 mph. Wings are getting sheeted this weekend.

$330, wow.. shipping tomorrow, thanks!