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General control line discussion => Open Forum => Topic started by: Serge_Krauss on October 17, 2017, 12:42:30 PM

Title: Shaft Extension?
Post by: Serge_Krauss on October 17, 2017, 12:42:30 PM
'not sure whether this belongs in the engine section, but here's my question.

Is there a reasonable way to get the old Fox .15/.15X to accept a spinner? I was all ready to finish contouring the nose of my "Peacemaker" to align with a 1 3/4" spinner, when I discovered that the shaft isn't long enough to accommodate the spinner back plate, prop, nut, and washer. Before I taper and/or round off the nose to better work with the prop minus spinner, I thought I'd ask whether I'm missing something obvious here. The plane has a hefty tripler on the left to calm the Fox vibrations. It too needs tapering. Shall I just go ahead and make the thing ugly? Thanks.
Title: Re: Shaft Extension?
Post by: Kim Doherty on October 17, 2017, 01:05:11 PM
Hi Serge,

Yes there is a simple fix but it requires a metal lathe. Bore the prop over size to accommodate a "T" nut (think a regular blind nut without the spikes and a longer threaded portion) There is plenty of thread inside the prop. Note that you do not want to bore the whole depth of the prop hub. Leave enough to center the prop on the shaft.  You will need to machine the nut to fit the bore and thread it. If you just need a couple of threads then you can chuck up the original steel nut and machine the back side to fit the new bore. I have done this to fit spinners many times.

The pictures show the basic principle. In this case the the nut was buried in the drive washer. No difference if it needs to go into the prop hub, just make a nut with a longer shaft.


Kim.

Title: Re: Shaft Extension?
Post by: Tim Wescott on October 17, 2017, 01:43:19 PM
What Kim said.  It looks like you've got an APC prop on there so you don't even need to bore out the front of the prop.

I did this on a plane that I inherited: whatever engine had been on there was longer from bolt to prop drive than the engine I put in, so I made a spacer and then didn't have enough threads.  I took a 3/8" bolt, drilled & tapped it for 1/4-28 (on a lathe -- this isn't something you can do accurately enough on a drill press), made a washer to match, and it's worked great for several dozen flights.  The OD of the nuts fits into the APC prop that I use, and all is well.

If you don't have access to machine tools and can't get it done locally, check with Jim Lee -- I'm sure he can get you set up for not too many $$.  I've seen some engines that come stock with a nut like that, but I couldn't name a brand beyond the well-respected Maybe-Saito.
Title: Re: Shaft Extension?
Post by: RandySmith on October 17, 2017, 01:57:28 PM
many nut for prop shaft extension will  work to do this for you, if you have a box of them from over the years  you may want to go thru them
Or  if you have a lathe  as they said  make one

Randy
Title: Re: Shaft Extension?
Post by: Norm Furutani on October 17, 2017, 02:02:32 PM
It would look like this: http://www.gravesrc.com/supertigre-prop-nut-g-2300.html (http://www.gravesrc.com/supertigre-prop-nut-g-2300.html)
Don't think you will find a stock item that will fit a .15 Fox. As mentioned, you need someone with a lathe.

Norm
Title: Re: Shaft Extension?
Post by: Curt D Contrata on October 17, 2017, 02:20:54 PM
http://www.gravesrc.com/supertigre-prop-nut-g-2300.html (http://www.gravesrc.com/supertigre-prop-nut-g-2300.html)


And, if ever in Orlando, Graves RC is a must. Great Hobby Shop, a rare treat.

Curt
Title: Re: Shaft Extension?
Post by: Ken Burdick on October 17, 2017, 02:23:43 PM
you should be able to buy an "extension nut" at McMaster Carr, possibly tower hobbies. Aluminum will work well and dubro may have it so check online hobby dealers.
Title: Re: Shaft Extension?
Post by: Norm Furutani on October 17, 2017, 02:24:19 PM
A bit off topic, but a cool step by step on how to make a prop extension. http://www.fineworks.tw/modules/xforum/viewtopic.php?forum=14&topic_id=187&order= (http://www.fineworks.tw/modules/xforum/viewtopic.php?forum=14&topic_id=187&order=)

Norm
Title: Re: Shaft Extension?
Post by: James Lee on October 17, 2017, 03:25:24 PM
Serge
Check your email..
Jim
Title: Re: Shaft Extension?
Post by: GERALD WIMMER on October 17, 2017, 04:16:01 PM
This should do the trick :
http://www.ebay.com/itm/60401-FOX-10-32-SHORT-ADAPTER-NUT-ONLY-ENGINE-PART-CONTROL-LINE-/252384232605?hash=item3ac345c49d:g:izYAAOSwInxXMPCG
Mecoa may have the longer 10-32 extensions too.
Regards Gerald
Title: Re: Shaft Extension?
Post by: M Spencer on October 17, 2017, 09:32:18 PM
I THOUGHT FOX 15s WERE  BANNED ! .  S?P

(https://static.rcgroups.net/forums/attachments/4/5/2/7/3/7/t8238869-117-thumb-FoxPropShaftExt.jpg?d=1442170673)

Ive used a Fox 3/4 Extn Nut on the !/2 in Extn Spacer on occasion ,
or just such a nut , if ye dinnae need  the spinner backplate fwd .
Title: Re: Shaft Extension?
Post by: Serge_Krauss on October 18, 2017, 11:52:40 AM
Fantastic! Thanks guys! I learned something from your posts. Jim has e-mailed me that he has what I need.
Title: Re: Shaft Extension?
Post by: Steve Helmick on October 22, 2017, 11:19:00 PM
An aluminum spinner backplate will help the situation a lot. Plastic spinners are not a bad thing, but plastic spinner backplates are always a problem in shaft thread lengths and also prop slippage. I'd suggest this one. Pretty affordable, various colors, run true, nice, and often used even on "serious" stunt models. Check with Dave Brown Products for the nut/washer parts you need. See MA ads.  H^^ Steve

https://www.towerhobbies.com/cgi-bin/wti0001p?&I=LXBMX8&P=0 (https://www.towerhobbies.com/cgi-bin/wti0001p?&I=LXBMX8&P=0)