What size spinner adapter nut do I need for a moki 1.8?

looking at a dave brown spinner.

10mm

i second that motion....Moki is 10mm

Yep, it is 10mm. But there are at least two different threads. Moki uses a 10x1mm. As opposed to 10x1.25mm (used on some Super Tiger, Zenoah and MVVS engines).

Moses

edit: Not sure Dave Brown makes an adaper for the Big Moki's. Try a Tru-Turn or in the alternative Harry Higley makes a 10x1mm spinner nut.

I machined my own spinner nut out of aluminum. It is a lot lighter thin a steel nut and yes it is a 10 mm *1.0 .dave brown uses a 10-32 on the other end. you will also have to bore out the back plate to 12mm. and an 18 /8 will not fit the spenner you have to cut bigger slots.

Or get a tru turn big bird spinner there made for bigger props.

I have a Tru-Turn adptor for a Moki 1.8 I will sell you cheap.

dave brown sells all sizes of nuts for your motor. thet are cheaper too. 5.95 for a x long 10 x 1 mm. www.dbproducts.com

Yep, Red Rover is correct, Dave Brown does indeed sell a 10x1mm adapter. I was looking at the Tower Hobbies site - seems that Tower just does not carry this part.

You definitely have to deal with the slot issue. Either you have to order a spinner with the right size slots or you may have to enlarge the openings yourself. Not sure what Dave Brown has in the way of slot options (seems pretty logical that Dave Brown could set you up with the proper slots). Tru-Turn has several different slot options - including standard slots, large "120" slots for APC props, "Big Bird" slots, and Menz slots for Menz props.

I want to run a Zinger 22x6 on my Moki 2.10. What is the proper slot option for this prop? ... I have no idea . I think I will forgo the spinner and go with a spinner nut or prop hub.

Moses

The Moki 180 is a little more complex than most. The threaded portion of the shaft is 10x1mm. Part of the shaft, closest to the prop washer, is not threaded and is 12mm. The length of the 12mm portion is slightly longer than the thickness of the Tru-Turn spinner backplate. What this means is the prop will have to be reamed to 10mm in front and 12mm in the back. The Moki shaft is also very miserly in length -- there is no extra length to play with normal adapter nuts. The Tru-Turn Adapter nut replaces both the front washer and nut. The nut portion of the adapter recesses inside of the washer, otherwise it would not have much thread on the shaft to work with.

Do you have to ream the spinner backplate to 12 mm for the 2.1 as well?

My 2.10 came in the mail today . That crankshaft does look a bit short.

Yep, the spinner backplate has to be reamed to 12mm for the 2.10 and apparently the 1.8 as well (according to the Moki Manuals). The Tru-Turn site recommends that they do this work. I guess your best bet is to order a spinner directly from them and have them do the machining on the backplate before they ship it (assuming you want a Tru-Turn spinner).

Moses

edit: typo

I have a FOX 8mm-10mm-12mm reamer and had no difficulty using that with a drill press on both the spinner backplate and the prop.

just ream , drill or bore the prop for 12 mm threw the nut should be 12 mm od . when you thread the nut on it will move in to the prop. I should make more nuts and sell them.

I did a bit of test fitting with the Moki 2.10 this evening. I put on a Zinger 20x8 prop, no spinner. I used the stock prop nut and washer. There is about 1/8” of crankshaft thread left. This only leaves about 4 threads for the Higley spinner nut (not quite enough … IMO).

It turns out the Zinger 22x6 has a thinner hub. With this combination about ¼” of thread remains for the Higley spinner nut (about 8 threads or 8 turns). This seem like it will work perfectly (and rather inexpensively I might add).

Moses

YOU should read my reply . when you screw the adapter nut on it gos into the prop. the nut I machined has at lest .500 of thread. the adapter nut is 12mm od same as the cranshaft so as it is screwed on it supports the prop.

lcgj, I don't understand what you are saying. I was just describing what I see.

Let me try again ... a picture is worth 1000 words. I though folks might benefit from seeing some actual dimensions, using an actual engine, prop and spinner nut combination.

Here is a pic of my Moki 2.10 with the stock prop nut and washer. The distance from the prop drive to the end of the crank shaft is approximately 1 5/16" (33.5mm)

The thickness of the stock prop nut and washer is approximately 7/16" (11mm). The stock prop nut does extend into the washer - but not into the prop as you can see from the picture.

The thickness of the prop hub of a Zinger 20x8 is a little more than 11/16" (18mm).

That leaves about 4.5mm of thread left (almost 3/16" - but the end of the crankshaft is chamfered. So actually there is about 1/8” of crankshaft thread left (a little more than 3mm). This only leaves about 4 threads for the Higley spinner nut (not quite enough … IMO).

Moses

Here is a pic of my Moki 2.10 with a Zinger 20x8 prop and the stock prop nut and washer. The prop has been reamed to 12mm.

As you can see from the picture, there is about 1/8” of crankshaft thread left (a little more than 3mm). This only leaves about 4 threads for the Higley spinner nut (not quite enough … IMO).

Moses

Here is a pic of my Moki 2.10 with a Zinger 20x8 prop and the stock prop nut and washer and the Higley spinner nut.

Moses

Here is a pic of a Zinger 20x8 prop hub (top) and a Zinger 22x6 prop hub (bottom).

The thickness of the prop hub of the Zinger 20x8 shown in the picture is a little more than 11/16" (18mm).

The thickness of the prop hub of the Zinger 22x6 shown in the picture is about 5/8" (16mm). With the Zinger 22x6 almost 1/4" of thread will remain for the Higley spinner nut (about 8 threads or 8 turns).

Moses

I am a machinist not a writer I have trouble explaining things in righting so i will try again . the adapter nut is threaded on bothe ends 10 mm by 1.0 and 10- 32. thare are to steps from the 10 mm side one is 12 mm and the other is the same as the washer i think it is .5 the 12 mm is the same as the cank shaft so as you tighten the nut it will move into the washer and the prop. the pic you have is the stock nut not the spinner adapter nut. the prop hole is 12mm the theads are 10 mm so thare is clerance for the nut wich has a 12mm OD step to a .5 OD step. I hope you can under stand this I wish i had AUTOCAD thin i could show you the adapter nut i made or camera.

Yep, I'm more of a writer than a machinist.

I'm going to read your post a few times to try to figure out what your part looks like. I would love to see a drawing or picture. I'm going to try to understand without the drawing or picture ... bear with me.

In any event, you can see what I am trying to do. My current plan is to use the stock prop nut and washer. I just want to thread a Higley spinner nut on. I think that there will be about 8 threads for the Higley spinner nut. I did not tighten the prop shown in the pictures. Things are going to compress a bit once I crank the prop nut down tight.

I hope that the folks intending to use a spinner find the dimensions useful. That crankshaft sure is "miserly" as hilleja pointed out.

Moses

edit: Hey lcgj ... you're a machinist ... do you think it is safe to thread the Higley spinner nut onto the end of the crankshaft if I only have about 8 threads.

I think it will work because thare is not that much force on the outer nut but i would not put a lot of torqe on it may be some 242 lock tight most of the load is on your inner not the outer one is just for the spinner wich just go 's around. My nut is all one peace not two. just the nut with 10 mm and 10 32 threads it goes from 12mm to .5 to .8 for thewrinch with four flats and thin it hase 45 angle to a .25 neck about .6 long. its about 1.6 long all to gather.

Ha ! .... I think I figured it out.

lcgj, your custom made nut basically looks like the picture below. It uses the stock washer and extends into the 12mm hole reamed into the prop - for some extra thread grip. It has a shoulder that is stepped up to 1/2" OD - so that it fits snug in the stock washer. Then it has a second shoulder to form the hex (or square) nut - so you can tighten it with a wrench.

It has 10x1mm threads on the crankshaft end and 10-32 threads on the opposite end - to accept a 10-32 hex bolt - to hold the spinner cone ... yes ?

Assuming I am correct, this is a nice design. What I like about it is that no counterbore is needed. The Tru-Turn adapter for the Moki 2.10 also reaches into the prop for maximum thread grip but the prop has to be counterbored. According to Tru-Turn, the portion of the adapter nut that extends into the prop has a 13.5mm (17/32") OD (I called and asked). So this requires a second machining step before you can install the prop.

Ha ! ... I'll bet you thought I wouldn't figure it out.

Moses

edit: fixed some typos and modified the drawing - also I did not draw the neck (basically a cone shape which should be on the right hand side of the drawing - I think).

YES that is close to what it looks like. GOOD JOB