Pee Wee Mounting Question

fargophil Sat Feb 05, 2022 10:49 am

Being the proud owner of the 200,000 ,020 I am getting ready to mount it to my test stand and want to know the usual screw size ot mount it. Since the back plate appears to be plastic and not wishing to break off any of the mounting lugs I am hoping someone can tell me what size screw will fit the mounting lug and not damage it?

706jim Sat Feb 05, 2022 10:57 am

Not sure what you mean by "200,000" the regular Pee Wee has a zinc backplate and will accommodate #2-56 machine screws or #2 hex drive servo mounting screws.
Anything larger will damage the lugs and mark up the tank.

fargophil Sat Feb 05, 2022 11:04 am

I had tried a #2 screw but it seemed to tight, I will give it another try. The 200,000 .020 is in reference to the engine I won by being the one to make the 200,000 post.

cstatman Sat Feb 05, 2022 12:43 pm

here is the table of sizes i've been collecting, looks #2

Mounting screws coarse wood
#2 x 1/2
2mm x 13mm long

.010 prop - 2-56 x 5/8”
.010 backplate screw - 2-56 x 1/4” filister head

.020 prop - 3-48 x 3/4”
.020 backplate screw - 2-56 x 1/4” filister head
.020 glow 25/64-48 tap

.049 prop - 5-40 x 1”
.049 stud - 5-40 x .8”
.049 backplate screw - 2-56 x 1/2” round head
.049 short tank - 2-56 x 3/4” fillister head
.049 long tank - 2-56 x 1” fillister head
.049 glow - 17/32-40 tap

fargophil Sat Feb 05, 2022 4:31 pm

Very helpful! Copied,printed and put up on my workshop wall.

cstatman Sat Feb 05, 2022 6:23 pm

oh my, i should have put naughty words in it, so they stayed up on the wall and made ya laugh more

Any luck with the #2?

fargophil Sat Feb 05, 2022 6:44 pm

yes and no. The yes part is I tried some #2 servo mount screws from RTL but the head hangs up on the seam between the fuel tank and the back plate. Rater than forcing it I ordered some #2 socket head screws that look to have a smaller diameter head. Shold be in early next week.

**944_Jim** Sat Feb 05, 2022 11:21 pm

Phil,
Be careful...you are talking about the plastic horseshoe backplate...right?

I'll dig out my plastic horseshoe backplate tomorrow and check. It may be different than the tank backplate. That horseshoe backplate is custom created by Jason_WI. That whole bundle of goodies is quite a haul!

706Jim: https://www.coxengineforum.com/t15451-200000-posts

Jason_WI Sat Feb 05, 2022 11:40 pm

These were the screws that shipped with the CEF backplates in 2019. Looks like they doubled in price since I last ordered them.

https://www.amazon.com/gp/product/B00Z3XEHJ4/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

A #2 socket head should fit there as well. The head needs to be small to fit in the recess in the backplate.

I didn't think the 200k engine would have been flown so I didn't include any mounting screws.

706jim Sat Feb 05, 2022 11:58 pm

[quote=

706Jim: https://www.coxengineforum.com/t15451-200000-posts[/quote]

Thanks. This slipped past me; hadn't seen it

getback Sun Feb 06, 2022 5:22 am

Damn that is expensive Look 12- cheaper > https://www.microfasteners.com/sts0210-2-x-5-8-socket-head-sheet-metal-screws.html and socket head better !

706jim Mon Feb 07, 2022 3:34 pm

I bought a bunch of #2 and #4 socket head servo mounting screws at Toledo a few years ago. #4 are obviously too large so I tried the #2 screws to how they fit one of my Pee Wee engines.

Turns out that there are three variations of #2 socket head screws. The oldest ones don't have either a washer or built in washer like the latest versions have. These fit fine without marking up the tank.

If you have the second style (Socket head screw with a washer) these will also work if you remove the washer.

The last type with the built in washer (usually sold as servo mounting screws) won't fit without the washer scratching up the tank body.

There are two other fasteners that can be used as well. #2 button head screws will work and look really slick. You just have to remember to thread the holes with a regular screw before installing them as the hex is miniscule and strips easily if you attempt to thread them into plywood.

Finally #2-56 machine screws and nuts also work well, but the extra work to fit the nuts is really not required for such a low powered engine.

So how's that for a long winded answer to a simple question?

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