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Motor winding/rewinding


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#51 Pablo

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Posted 07 November 2007 - 08:24 PM

No problem frying your own work, it can be re-done. Endbells, unfortunately, often melt first. Just something to keep in mind... :)
Paul Wolcott




#52 havlicek

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Posted 07 November 2007 - 09:44 PM

Endbells, unfortunately, often melt first. Just something to keep in mind... :)

... are you kidding me, that's the best part!

From my post above:

I also got a Parma D-can setup to use for testing out some of arms Ron is sending, never messed with one before. Can anyone tell me what's up with the weird springs on these things?

... anyone?
John Havlicek

#53 Pablo

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Posted 07 November 2007 - 10:01 PM

:laugh2: OK John, I can sense you love to walk on the wild side :D Try 15 turns of 24 :) That should be a :bomb:

On a serious note, since nobody responded to your question about "weird springs", I think we need a photo to understand the question.
Paul Wolcott

#54 havlicek

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Posted 08 November 2007 - 06:17 AM

I'll try and get a photo up, but the brush springs are bent at 90 degrees where they would contact the brush. They run into the brush carriers... perpendicular to the comm instead of tangent to the com, as they would in a C-can or any other motor I've used???

I understand I've been away for a long time but... my how things have changed!
John Havlicek

#55 Bill from NH

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Posted 08 November 2007 - 06:36 AM

John,

Sounds like you're using some stock 16D springs. The idea is for the end of the vee on the short leg to push the brush in toward the comm rather than to the sides of the brush hood.
Most people change to a quality aftermarket spring such as the Champion lights (red) which have conventional straight legs. Those 16D springs can be made to work but require a lot of tweeking. Sometimes clipping about 1/32" off the short leg helps.

Bill Fernald

 

You have to be odd to be #1. :laugh2: 


#56 havlicek

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Posted 08 November 2007 - 06:46 AM

... Ahh, mystery solved!

Thanks, Bill.
John Havlicek

#57 havlicek

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Posted 09 November 2007 - 03:06 PM

Rick... I got the winder and it's perfect, many thanks! This will make the process much more uniform and predictable. I drilled and tapped the bottom of the stem for a 10/24 screw and mounted it on a board so I can just clamp it to whatever surface I want:

Posted Image

Now I'm just waiting on the arms to get here.
John Havlicek

#58 Pablo

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Posted 09 November 2007 - 07:24 PM

Holy mackeral, John, look at the size of that wire!

What are you rewinding, an alternator for a John Deere? ;) :lol: :) :crazy: :clapping: :sorry:
Paul Wolcott

#59 havlicek

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Posted 09 November 2007 - 07:45 PM

That's nothing Pablo... I was thinking about dipping some #10 copper ground wire in lacquer. I figgered two or three turns would have been about right. :D
John Havlicek

#60 Hworth08

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Posted 09 November 2007 - 08:11 PM

Nice-looking rewinding machine. Rick does very nice work!

The base, while nice, is WAY too big for my desk though, I'd take me a week to clean off a spot that size! :)

Something to watch for, check that the new comms will fit if using a vintage endbell. Trying to remember, seems maybe the Chinese comms mostly fit, the American arm comms I believe are too big unless you radius the Mabuchi endbells? If using vintage cans and bells, it's probably good to trial fit the whole setup before winding. Some of the new arms as per rules are a fair amount longer than the Mabuchi arms were.
Don Hollingsworth

#61 havlicek

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Posted 11 November 2007 - 07:26 AM

Thanks for the 4-11 Don... I've already run into that. I really didn't have much choice about the base since my vise is in the garage and it's already getting pretty c-c-cold here. ;-)

Ron... if you're looking in here, I got those arms... they will be a great help, much appreciated!
John Havlicek

#62 havlicek

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Posted 12 November 2007 - 06:43 AM

I got my first one done yesterday as sort of a test to prove I'm on the right track and everything is working. The thing spins-up nicely... seems very strong in a stock D-can, although it could definitely benefit from some balancing and a proper setup. Biggest challenge (after cramming that wire on there!)... was getting the last comm tab soldered and tightened-up with two pieces of wire on it. I'm looking forward to trying this on a Mura C-can arm (whenever they get here?) since the comm is a little more generous.

BTW... the winder worked great and made this much easier for me... especially with such heavy wire (#24).
John Havlicek

#63 Bill from NH

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Posted 12 November 2007 - 08:00 AM

John, do you recall how much timing you put on that arm?

Bill Fernald

 

You have to be odd to be #1. :laugh2: 


#64 havlicek

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Posted 12 November 2007 - 11:43 AM

John, do you recall how much timing you put on that arm?

... sure Bill, I don't have one of those protractor timing-degrees thingies but the comm tab for the pole you're working on is lined-up with the leading edge of the next pole. Just eyeballing this, you should be within a couple of degrees of consistency if you use that as a guide. I got that from one of the helpful folks here that have contributed to this thread and it seems to work really well.
John Havlicek

#65 havlicek

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Posted 15 November 2007 - 02:43 PM

I'm getting in the swing of things pretty well now and have finished a couple of "keeper" D arms. Here's one of my hand grenades:

Posted Image

I don't know yet how it will actually run, but it sounds pretty impressive anyway, :D
John Havlicek

#66 Pablo

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Posted 15 November 2007 - 03:12 PM

Is that one balanced on the R-Geo, or are those just the original balancing holes?
The winds look nice!
Paul Wolcott

#67 havlicek

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Posted 15 November 2007 - 03:23 PM

Hi Pablo,

I balanced it on razor blades; the arm was an unbalanced 16D I got from Ron. I made a block with slots for razor blades and spent some time trying/marking/drilling and it came out fine. The thing sounds like a dentist's drill on steroids and really dims the light on my homemade power supply :D , but these arms have very little room at the comm so I couldn't tie it up. I'm hoping that the heaviness of the wire itself will help keep it from flying apart??? Anyway, this stuff is really fun!
John Havlicek

#68 Ron Hershman

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Posted 15 November 2007 - 10:18 PM

Looks like you're having fun now... great job.

#69 havlicek

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Posted 16 November 2007 - 06:52 AM

Thanks, Ron...

The arms you sent have been just the ticket for me to try to figure out what was going on here and to get my feet wet again. I'm still waiting on the blank C-can arms and comms from Mura to arrive (?), but in the meantime I've been able to re-learn some about winding and balancing.

The D can setups from Parma are... interesting. The air gap is large enough to drive a Jeep through, the springs make no sense at all (I tossed them as per suggestion here), and the design of the whole endbell (brush hoods, spring posts, etc.) probably could benefit greatly from insulating the springs and going with shunts. The magnets don't seem particularly muscular either, but I have no way of measuring that. All-in-all, I'm happy that these arms spin-up as well as they seem to and they'd probably do significantly better in a well set-up can with beefy magnets.

Right now... the arms seem to prefer heavier springs, but track-testing would be the real proof of that. I'm sure that ball bearings would also make a big difference over the oilites. Thanks again for the arms!
John Havlicek

#70 Ron Hershman

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Posted 16 November 2007 - 09:15 AM

Yes, the D-can air gap is huge. China just uses a "shelf" magnet for this motor. There used to be thicker mags, but they were much weaker than the thinner ones.

The springs are again Chinese specials. Just brass and good enough to do the job for a "toy" motor. Use a good three or five coil spring with insulation and shunts and you will be fine.

The magnets in the D-can are quite strong and as strong as most C-can magnets. The C-can mags have more energy than the D-can mags, but the D-can mags are better than any '60s vintage magnet. Shimming the magnets to a tighter air gap will make the motor even run better.

#71 havlicek

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Posted 16 November 2007 - 05:10 PM

... As always, thanks for the info, Ron! I finished another one and went for the gusto this time... and this one really sings soprano (or whistles)! The ones I had done before this were a little mild, so I figured why not build a better bomb? :-) I also realized I probably made a mistake with the other arms by using 60/40 to solder the comm tabs, so I used silver solder this time and have gotten better at doing a neater job soldering those tiny-little tabs. :-)

Posted Image

I'm definitely thinking this one deserves to be treated right, so I want to set up the can. If anyone knows before I destroy a perfectly good can... are the magnets glued in on the Parma D-can... or are they just held in place by the metal "fingers" that seem to be crimped at the edge of the magnets? I'd like to remove them and shim them up, but they don't budge.
John Havlicek

#72 Ron Hershman

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Posted 16 November 2007 - 05:39 PM

Which Parma can do you have??? The Deathstar or the Rotor can?

The magnets are held in the Parma Deathstar can by the two "shim" looking retainers on the top and bottom of the magnets.

Just sit the can on your bench with the oilite sticking up in the air and using a small screwdriver, a small hammer, and some light tapping and the magnets will slide down.

The Rotor can has the can fingers bent over holding the magnets in place. They may have put a bit of super glue on at the factory in China. Just soak the can in some acetone for a hour or two and then try tapping them out as above.

#73 havlicek

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Posted 16 November 2007 - 10:04 PM

It's a Rotor setup and I got the magnets out, but I did have to soak them as you suggested after prying the can fingers, although I couldn't see any residue in there from glue afterwards (?).

I did a little bit of a setup and put in a bearing in the can end of the motor, some better springs, and it really sounds nice! With this one... I'm afraid to let it wind all the way up, in a good way! Mura emailed me to say the C-can arms are on the way... perfect timing.

Thanks again for all your help.
John Havlicek

#74 havlicek

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Posted 21 November 2007 - 07:06 AM

So after experimenting with both the long and short D-can arms (I forget what they are called)... with both #24 and #26 AWG wire, it looks like the #24 at either 15 or 16 turns is the way to go. I've been revving these things to full RPMs with no load for a while now and they seem to be holding up fine. No matter what recipe I try though... the #26 arms always seem a little milder for some reason (the electrical engineers in the house could probably explain why). A whole bunch of the first #24 arms I wound (mostly 18-19-20/24) were pretty tame also compared to the 15 or 16/24 ones.

Jairus... if you see this, I'll send you one of the newer ones to replace that "puppy-dog" I sent you. If you don't have any use for it, you can always use it for a sinker. :D
John Havlicek

#75 Prof. Fate

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Posted 21 November 2007 - 12:10 PM

Hi John,

"Screaming" isn't the issue. For "scream", you could try 12/22!

But on the track, depending on the track and car, you will likely find that your "screamer" isn't the hot motor.

Fate
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#76 idare2bdul

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Posted 21 November 2007 - 01:20 PM

I've been revving these things to full RPMs with no load for a while now and they seem to be holding up fine.

No load at full power isn't a good idea, especially with a home-wound arm. Throwing the wire off your arm or blowing up the comm can be a problem. In the early '80s the military tested an arm at over 250,000 rpm at 9 volts no load before it blew. They were looking to power a gyroscope for smart bombs.

One of my friends blew up a motor and imbedded parts in his hand by blowing compressed air into the motor to spin it up with no brushes in the motor.
The light at the end of the tunnel is almost always a train.
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#77 havlicek

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Posted 21 November 2007 - 02:01 PM

"Screaming" isn't the issue. For "scream", you could try 12/22!

But on the track, depending on the track and car, you will likely find that your "screamer" isn't the hot motor.

... well, that's understood :) as I have done this before and realize that torque is just as important as revs (although to a certain extent a balance in favor of one over the other can be mitigated with the right gear ratio). I have also experimented with winds above and below, thanks to the supply of arms from Ron (thanks again!). I have also installed these arms in cars and revved them to try and get a "feel" for how fast they spin-up... not just how high they rev. Still, thanks for the input!

No load at full power isn't a good idea, especially with a home-wound arm. Throwing the wire off your arm or blowing up the comm can be a problem. In the early '80s the military tested an arm at over 250,000 rpm at 9 volts no load before it blew.

I can always wind more. :D

One of my friends blew up a motor and imbedded parts in his hand by blowing compressed air into the motor to spin it up with no brushes in the motor.

While I can't really see the point in that exercise, as a carpenter I've lost bits of my hands and other parts over the years. After the wounds have scarred-over and the memory is still fresh I have learned to be prudent about safety. Still... I certainly don't advocate doing anything dangerous. However, we aren't talking about experimenting with rocket engines or explosives here. This stuff is pretty "safe" in the scheme of things.
John Havlicek

#78 havlicek

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Posted 28 November 2007 - 03:58 PM

I got the Mura blank arms and commutators in and did one up:

Posted Image

These are really nice arms. The stack profile allows for a lot of room to wind and the comm has loads of room on the tabs to solder in that nasty #24 wire. :-) If anyone here (besides Pablo :D ) is at all interested in doing some motor winding, these are by far the nicest blanks I've messed with so far.
John Havlicek

#79 MarcusPHagen

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Posted 29 November 2007 - 05:24 AM

Thanks for posting your results, John. Those _do_ look nice! Once I get caught up on housecleaning for the holidays (the "honey-do" list) and get to my watchmaking backlog, I'll have enough cash to buy one of Rick's rewinders and a few blanks with comms to do some winding. It'll be great to be back.
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#80 havlicek

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Posted 29 November 2007 - 06:49 AM

Hey Marcus,

I hear you about the cash thing... especially with the housing market in the toilet (I'm a carpenter/builder). I've had really good results rewinding those D-can arms as well and have some ready to go into a car when I get that sorted. I also got (thanks to Pablo!) a Champion blank that was excellent, but these Mura C-can blanks are the best so far. They would be really easy to do a double-wind on as well, thanks to the room at both the comm as well as on the stack itself. When I get the balancer from Rick, I'm going to go over all the arms I've kept so far and see if they can be improved a bit. The last piece in the puzzle is Kevlar and I found some on Amazon for pretty cheap (like $2 for a 50 yard spool). These last arms I've been tying-up with fiberglass... but I have to believe that Kevlar will be even more "bulletproof". ;)

So my little trip back into winding/rewinding arms has confirmed that:

1) With a little practice, you CAN whip-up some armatures that will be as good as the factory stuff! You can wind them hot as heck... or not so hot, but in the end it's cool to have a motor you wound sitting in a car you built. Now if I could only paint as well a Jairus or Noose... or build a chassis as good as Rick and some others around here... (sigh).

2) The D-can arms from Ron were super as a way to get back into all this. Being as cheap as they are... and easy to unwind/salvage... you can afford to try things out and not worry too much. When they're done, those arms can be "keepers", too. Their basic components may not be "top shelf"... but they work fine. I've got one D-can setup that rips... and have three backup arms. :-)

3) There's really no "black magic" involved here. This stuff can easily be learned and polished-up with a little practice. Pablo is someone who proves that and like he says... "it ain't braggin' if you can back it up!".

4) Once you get comfortable with all this, the Mura C-can blanks are the bee's knees. The problem with them is that for an arm and a com, you're paying $14 and you don't want to mess up at that point.

5) While static balancing is not the best... it's entirely appropriate for this stuff and all it takes is some patience and care to get these arms singing soprano. It's just a personal preference of mine to "do it all"... but I can see how others would want to send their arms out to be trued, epoxied, and balanced.

I've learned or relearned... I can't remember exactly what is stuff I knew and forgot or just stuff I never figured out before... a bunch from all this, which was cool in itself. You know what they say about once you stop learning... :)
John Havlicek

#81 GTPJoe

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Posted 29 November 2007 - 10:31 AM

John,

So when can we start putting our orders in for "custom" arms??

Seriously! I wanna go to the local raceway and have the other racers asking..."So what are you running?" and replying ..."It's a Havlicek 24!!".

How cool would that be!!

I'll buy some single 24s for my Mura setups. 17t of 24 please!

Awesome job!
GTP Joe Connolly

In theory there is no difference between theory and practice.
In practice there is.

#82 havlicek

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Posted 29 November 2007 - 11:14 AM

Hi Joe,

I'm not looking to go into the arm-winding business, but I am going to give away a couple just to have folks give me their impressions. If you want, you can get one of those. With the Mura blanks costing about $14 each and around an hour and a half in labor for each arm, I would have to seriously set up for mass production to make it all economically feasible-attractive. After I get the "Rick-Balancer" and the Kevlar, I'll do a couple to send out. This way... nobody can complain about the cost :-)

BTW... 17 turns of #24 should be a nice medium-spicy meatball. :-)

Take care, Joe.
John Havlicek

#83 Pablo

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Posted 29 November 2007 - 07:31 PM

Remember, on the R-Geo balancer, taper the ends of the shaft for best results. The more precise and fine the taper, the easier it will be to find the heavy spot.

Also, with the amount of care that goes into a Havlicek, you may well find it difficult to decide on a heavy spot. In such a case, you must force yourself to believe you did such a careful job, the arm is already very close to being balanced perfectly. Taper some junk arms first, and get the feel of that balancer. It works.

Dynamic balancing is overrated and you can true a comm by using a poor man's lathe (drill) and 2,000 grit sandpaper. WhoooHoooo, somebody just shoot me. :yes3: :pardon:
Paul Wolcott

#84 slotbaker

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Posted 29 November 2007 - 08:08 PM

Great thread, John.

A few months ago, I did my first rewind on a 36D in 40 years, and it was gratifying to have it work. It even ran pretty quick, as well. :)

Remember, on the RGeo balancer, taper the ends of the shaft for best results. The more precise and fine the taper, the easier it will be to find the heavy spot.

I asked this question in another thread, but it must have been overlooked.

With Rick's balancer, how accurate does the tapered point have to be relative to the centre line of the shaft? I'm thinking that the magnetic 'pull' would be greatest at the very end of the point, and therefor be the pivot point of the arm. Then, if the point was not perfectly on the centre line, could the balance be affected?? :blink:

If so, then by being a few thou off centre, could it result in significant weight out of balance?

I love the simplicity of the balancer, and maybe I'm overthinking a non-existent problem.
:unsure:

Steve King


#85 havlicek

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Posted 29 November 2007 - 08:15 PM

Thanks for the reminder, Pablo... I had been told that by Rick as well and it makes sense. The smaller the contact point, the less friction and whatnot. I have a bunch of arms here... both keepers that I want a second shot at balancing... and junkers that I can experiment with.

I wonder what your experience has been with static balancing. So far, I am certain about a small error point past which I can only get by luck. What I mean by that is I can balance two arms and have visually the same result using razor blades... but one will run smoother than the other. Of course, the faster the arm spins... the more noticeable any small errors will be. As well as my best D-can arm runs... my first try with the Mura C-can blank seems much stronger still (!?), but I notice some small vibration. I'm hoping to get a little more in balancing precision from the R-Geo balancer. Between that and tieing the arms with Kevlar... I'm feeling more confident about these things every time I do one.

Here's another question for you Pablo... or anyone else looking in that knows. While surfing the net for info about Kevlar, I came across a forum somewhere and someone said that using super glue on the Kevlar was a super-strong and heat-resistant way to use the stuff. Does anyone know what the safe working temps for cyanoacrylate are versus generally good (but not NASA-spec) epoxy?
John Havlicek

#86 Pablo

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Posted 29 November 2007 - 08:39 PM

Steve, I'll just repeat myself, "The more precise and fine the taper, the easier it will be to find the heavy spot."

A perfect 45 degree taper would be ideal. Me? I just chucked up my arm in a drill, donned eye protection, and hit the ends of the shafts with a spinning Dremel. No machine shop here. :laugh2:
Paul Wolcott

#87 slotbaker

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Posted 29 November 2007 - 08:52 PM

I guess it's just a case of suck it and see.
:)

Steve King


#88 havlicek

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Posted 29 November 2007 - 09:10 PM

Steve,

Like you, I get a charge from doing this and comparing the arms I've wound to some Grp20s I have here... they seem stronger. Pablo's method of having the arm spinning in a drill and hitting the ends with a Dremel will produce a pretty darned well-centered point on the shaft end... certainly good enough for all this. The razor blade thing has other more significant limitations as well. A tiny amount of runout of the shaft itself could make the arm appear to be out of balance. Seemingly invisible particles on either the shaft or the blades seem like boulders and will stop the arm from rotating. Then there's the whole deal about handling razor blades themselves... and those edges go dull pretty fast.

Like Pablo... I don't have any machining tools here, I wish I did! You can get by just fine though with the basic stuff.
John Havlicek

#89 Pablo

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Posted 29 November 2007 - 09:33 PM

A tiny amount of runout of the shaft itself could make the arm

I'll remind you again, don't spend your precious time and effort on arms with bent shafts. Not really a concern when buying quality new products from known sources, BUT vintage arms found on eBay are suspect, as they have probably been inspected, rejected, and repackaged.

BTW, John, how straight is the Champion blank? I never checked it. As far as I know, it is original, and unopened. I would never send a reject to a friend. :D
Paul Wolcott

#90 havlicek

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Posted 29 November 2007 - 09:41 PM

... Well, in keeping with my low-tech methods... I don't own a dial indicator :D, but it seems straight and presented no problems balancing it. It's a strong runner right now (THANKS!). Still, when you're dealing with things on this scale visually unnoticeable runout could mess things up. Like you, I wouldn't have much faith in a vintage arm from eBay. As long as there are quality blanks (like the Muras!)... why bother?

BTW... I did some quick checking and cyanoacrylate glues aren't very well-suited to high-temps apparently.
John Havlicek

#91 Bill from NH

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Posted 29 November 2007 - 10:13 PM

I just chucked up my arm in a drill, donned eye protection, and hit the ends of the shafts with a spinning Dremel. No machine shop here.

This procedure works great for creating a height gauge (scribe) when making inline brackets for FK type motors, too. :)

Bill Fernald

 

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#92 Prof. Fate

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Posted 30 November 2007 - 01:27 PM

Hi,

Do NOT use cyanoacrylate glues for this. When CA burns, the fumes are toxic.

Fate
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#93 havlicek

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Posted 30 November 2007 - 05:34 PM

...and a 26 double wind (something different). This one's not going to get tied-off, epoxied, and balanced until after I get the Kevlar... but that's the easy part :)

26_dbl.jpg
John Havlicek

#94 havlicek

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Posted 02 December 2007 - 01:21 PM

... And here it is fresh from the oven. :) All tied-up with Kevlar and epoxied.

Double_26_Tied.jpg

Now, with my R-Geo balancer on the way (thanks, Rick!) I feel confident that I've taken this stuff as far as I need to to get solid performance from home-brewed arms. The RGeo winder has been a GREAT help here as well... not just for the actual arm winding, but it also makes a dandy "vise" for working on the arms after winding for silver-soldering the comm tabs and tying-off the arm with the Kevlar. If I can do it... anyone can.
John Havlicek

#95 Pablo

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Posted 02 December 2007 - 01:43 PM

Awesome. :D Looks like a missile. ;)
Paul Wolcott

#96 Jairus

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Posted 02 December 2007 - 02:19 PM

That is beautiful work there, John! Have you tested any of them on the track yet?

Jairus H Watson - Artist
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#97 havlicek

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Posted 02 December 2007 - 04:33 PM

Thanks, Pablo and Jairus... hey, Jairus, I'm looking for a test pilot, and the learning arm I sent you is probably better used as a sinker than to go into any of your creations. Check your PMs... hokey-dokey?
John Havlicek

#98 slotbaker

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Posted 02 December 2007 - 05:29 PM

All looks great, John.

Just need a trademark arm dye, eh.

:)

Steve King


#99 Jairus

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Posted 02 December 2007 - 08:10 PM

Sinker? What are you talking about, Willis? ;)

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#100 havlicek

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Posted 02 December 2007 - 08:22 PM

... That's s'posed to be "watchoo talkin' 'bowt, Willis?" :D

I cleaned-up the comm on the 24 single fer you, Jairus, and wrapped it up. It's going out tomorrow morning... Thanks!
John Havlicek





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