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Spinners. . . yet again! (Read 428 times)
Reply #10 - Jan 22nd, 2019 at 8:12pm

Ed OBrien   Offline
Junior Member
I Love YaBB 2.5 AE!
Manchester, CT

Posts: 51
**
 
Excellent. I actually have one of those. I never thought of using it for this purpose. I like it. That should get the hole down to a manageable size. Thanks.
 

Cheers,
Ed OBrien,
Manchester, CT
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Reply #9 - Jan 22nd, 2019 at 2:17pm

Sky9pilot   Offline
Administrator
Stick & Tissue
Kelso, WA 98626 USA

Posts: 10223
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Often the nose button is recessed into the nose block to give the spinner a closer fit to the cowling/fuselage nose.  The other option if the spinner is deep enough is to recess the rear of the spinner backing plate so the gap is reduced this way.  I've used a dremel bit for cutting/sanding disc that used a very small screw that passes through the disc and screws into the bit.  This will work on ply up to 1/16" thick.  It's the bit labeled "G" in the attached picture!
Tom
 


If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Reply #8 - Jan 22nd, 2019 at 12:58pm

Ed OBrien   Offline
Junior Member
I Love YaBB 2.5 AE!
Manchester, CT

Posts: 51
**
 
So here is the situation:

Upper left corner of photo: Spinner sanded and hollowed out.

Upper right corner of photo: Wood dowel use as a mandrel and then dug out of shaped spinner so sanding the inside of the spinner could take place.

Lower left corner of photo: Now I need a backplate (or base) for the spinner. The one here was made by my some many years ago for the same model. Of course it is does not match the spinner. In order to true up the backplate and right size it, I need to put a mandrel in it. Put it in the drill press and sand away.

I have 2 problems with this.

1)  Anything I might use as a mandrel requires way too big a hole for the prop shaft. So how do I fill the mandrel hole with something with a properly centered and sized for the prop shaft?

2) lower right corner of photo: Note the Peck thrust button. I’m going to end up with an excessively large gap between the back of the spinner and the nose block.

I have seen oodles of photographs over the years of rubber powered models with great looking spinners. What have I missed?
 

IMG_0872_002.JPG (1697 KB | 5 )
IMG_0872_002.JPG

Cheers,
Ed OBrien,
Manchester, CT
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Reply #7 - Jul 29th, 2018 at 5:29pm

Ed OBrien   Offline
Junior Member
I Love YaBB 2.5 AE!
Manchester, CT

Posts: 51
**
 
I finally got off my duff and used my birthday earlier this month to secure a drill press. That turned out to be an exercise in aggravation. But, today I picked up my Craftsman 10 inch drill press. The end result is a spinner shaped object. This was a potential mold for a tail turret for my son's Privateer. He did not use it as planned so I chucked it into my brand new drill press and went to work. At 71 I have finally gotten the first step in spinner making done. There are still a number of things I have not yet worked out but this is no longer a problem. It did make a nice pile of saw dust but a shop vac took care of that. Gotta get back on that Hurricane.
 

IMG_0564.JPG (1946 KB | 12 )
IMG_0564.JPG

Cheers,
Ed OBrien,
Manchester, CT
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Reply #6 - Jun 30th, 2018 at 12:08pm

Sky9pilot   Offline
Administrator
Stick & Tissue
Kelso, WA 98626 USA

Posts: 10223
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Unless you can control the speed of the dremel tool don't use it to make spinners.  I have used my variable speed hand drill for years before I got my drill press.  Do this over the trash can because there'll be lots of balsa dust and a vacuum doesn't hurt either.
 

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Reply #5 - Jun 30th, 2018 at 12:06pm

Sky9pilot   Offline
Administrator
Stick & Tissue
Kelso, WA 98626 USA

Posts: 10223
*****
 
Brass tubing for all bearings much better... You want as close a fit for the music wire to the tube as possible also.
 

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Reply #4 - Jun 30th, 2018 at 10:27am

Bargle   Offline
Full Member
Oh crumbs
East Tennessee

Posts: 129
***
 
Do not use aluminum tubing for the center shaft. Learned that the hard way.
 

Sure it's a wrinkly mess, but it flies.
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Reply #3 - Jun 30th, 2018 at 7:56am

New Builder   Offline
Senior Member
Amherstburg, Ontario, Canada

Posts: 820
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You are on the right track with the drill press, probably a bench type will do the job and turn it fairly slow. Be very cautious with the Dremel, mine is a constant speed and at 18,000 RPM lots of things come loose and move at high speed.
Mike
 

Have no fear of perfection - you'll never reach it. (Salvador Dali 1904 - 1989)
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Reply #2 - Jun 29th, 2018 at 1:32pm

Ed OBrien   Offline
Junior Member
I Love YaBB 2.5 AE!
Manchester, CT

Posts: 51
**
 
Thanks. I'll give it a go before I start the rest of the model.
 

Cheers,
Ed OBrien,
Manchester, CT
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Reply #1 - Jun 28th, 2018 at 11:19pm

Sky9pilot   Offline
Administrator
Stick & Tissue
Kelso, WA 98626 USA

Posts: 10223
*****
 
There are several ways to do this.  Lots of modelers use a variable speed hand drill.  They take a balsa block or laminated block of the proper size in length and diameter of the desired size.  You want the grain to run from the base to the tip of the spinner.  Cut a female pattern from the plan to check the spinner from time to time for accurate  shape.

It also helps to cut a ply circle backing plate at the base of the block to be turned.  Drill a hole at the center of the block to be turned.  If you have a drill press this will assure accuracy of a vertical hole to glue a dowel or if you have an old 1/8"  drill bit to glue into the block for turning. 

Trim off the corners of the block for easier turning.  If you have a drill press leave the block on the drill press and use the slow speed if it's variable speed drill press.  The ply backing plate will help keep you from sanding the base too small.  You'll want to keep the base plate right at the size of the mating surface of the spinner and the fuselage.

Start with coarse sandpaper 80 grit or so to ruff in the shape.  Then move to the finer grit when you're closer to the exact size you desire.  Once you get to the final shape finish off with 400 grit wet/dry sandpaper dry.  Remembering to use the female template over the spinner to confirm shape.

Once you have the shape you can then soak the glue with acetone to loosen the glue and remove the dowel or drill bit so the spinner can be hollowed out if you're going to use this as the spinner.  The other option is use this as a mold for plunge molding or vacuum forming a spinner.  Because it's a spinner you'll want to use thicker plastic so it will be more resilient to lawndarting!
Here's a quick CAD drawing to assist in the words above.
Tom
 

making_a_spinner.PDF (60 KB | 49 )

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Jun 28th, 2018 at 7:39pm

Ed OBrien   Offline
Junior Member
I Love YaBB 2.5 AE!
Manchester, CT

Posts: 51
**
 
OK, so I need a balsa spinner about 7/8" in diameter and 3/4" long. How does one go about "turning" one? What to use, a Dremel or a electric hand drill. I have considered a drill press. I know that the big, hunky (and the smaller ones) are not designed for side pressure. But, come on, how much damage can I do to one of those by making a spinner now and then?

I'm thinking that even if I use my Dremel to "turn" the spinner, somewhere along the line I'll need a drill press anyhow.

My main concern with the Dremel is the high RPM. I think I will need some sort of backplate?

I have seen a good bit of info on molding one from a balsa plug, and I may do that. But getting the balsa plug is still a bit of a mystery. That is one thing I don't remember Flying Models covering in detail. But I could be wrong.
 

Cheers,
Ed OBrien,
Manchester, CT
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