170 replies to this topic

[havlicek]

All looks great, John.

Just need a trademark arm dye, eh.

Hey, thanks, Steve! There's enough work in these things as is. I figure that polishing the arms will be my "color".

[mdiv]

John:

You're an inspiration!

Now, for a picture-blessed how-to article... hehehe!

[havlicek]

Thanks, Mikey... but I'm just trying to share my enthusiasm for something I think goes hand-in-hand with scratchbuilding chassis and painting bodies. I can do the picture thing, but I'm a little embarrassed to be doing something like that on a forum where some of the greats of all time are probably watching this thing with amusement. It would be better if someone like a Bob Green (I think that's his name) would do a how-to, rather than a hacker like me. I do feel pretty confident again about the whole process after all these years... kinda like riding a bike.

I've also started to send out a couple of these things to get some trusted opinions from people that already obviously know how to set up a motor properly. I think they're fine... now to see if others think so???

[Hworth08]

Re-winding does fit Slotblog well but how hard can it be? The secret is properly matching an arm to a set-up that is well designed for a certain chassis, body, track, weight, driving style, and power supply, plus keeping the motor alive.

A pretty tall order.

[havlicek]

10-4 Don... and those are good reasons why winding your own arms can be such a satisfying aspect of building and running slot cars. Once set up, a person can more afford to wind a whole "quiver" of arms that suit different purposes... tracks, chassis etc. It does take a little noodling-around to get a feel for what's going on with these things and I've only scratched the surface so far myself, but it hasn't taken long to get fairly confident. I've said it before, but there's a whole heap more involved in building great a chassis like the ones you see here every day. This is easy compared to that... just that you're working on a smaller scale.

Of course, the downside is that as far as I know, these motors don't have a "home" in any organized division so they would be strictly for the fun and pride of running what you made. Sort of the slot car equivalent of a shadetree mechanic heading out to the Dairy Queen in his Nova SS that he worked on all week. :-)

[Pablo]

I'm a little embarrassed to be doing something like that on a forum where some of the greats of all time are probably watching this thing with amusement.

I disagree. The "Greats of All Time" on Slotblog derive their amusement from seeing new people get enthused. Those who derive negative amusement from watching folks build stuff, well, they don't last long here. I've seen it.

[havlicek]

OK... tell you what then, Pablo. I'll do the "how to" thing (at least my method of "how-to") if you agree to chime-in and tell me when I'm doing something you think is dumb. Then we can have a better "how-to" that might help others. I'll be able to do another arm in a day or so and will document the whole mess with pictures.

[Hworth08]

Of course, the downside is that as far as I know, these motors don't have a "home" in any organized division so they would be strictly for the fun and pride of running what you made. Sort of the slot car equivalent of a shadetree mechanic heading out to the Dairy Queen in his Nova SS that he worked on all week. :-)

Hi John!

The only home a hand-wound arm has in organized racing is in G-7 open motor racing. All other arms must be machine wound and tagged.

A "problem" with any arm under racing conditions is that they vary quite a bit, even when wound to the same specs on the same machine.

For what you're having fun doing, that doesn't matter one ounce! Most of my arm winding is Russkit 22 type motors that don't even have any brush holders. 110 turns of 34 is about the melting point, the stock Mabuchi mags are saturated at that point. Somewhat mild (to say the least) compared to your arms! Mine would be more like riding a bicycle to the Dairy Queen.

I sure don't intend to reduce the joy of re-winding but several people read these posts. I feel a bit obligated to try to define the boundaries of an arm, to make readers aware that there's a lot more to a good arm than wire size and number of turns. Perhaps the reason most active racers are glad the arms are factory-wound.

[havlicek]

Hi Don,

The only home a hand-wound arm has in organized racing is in G-7 open motor racing. All other arms must be machine wound and tagged.

A "problem" with any arm under racing conditions is that they vary quite a bit, even when wound to the same specs on the same machine.

... Yep, I kinda figured that but I would bet that if a person wanted to put in the time they could come up with a competitive wind even against those motors. I don't know anything about the "high-priced spread", but maybe coming up with the raw materials might be a problem there... but still.

For what you're having fun doing, that doesn't matter one ounce! Most of my arm winding is Russkit 22 type motors that don't even have any brush holders. 110 turns of 34 is about the melting point, the stock Mabuchi mags are saturated at that point. Somewhat mild (to say the least) compared to your arms! Mine would be more like riding a bicycle to the Dairy Queen.

... The other benefit is that for my stuff you don't need to worry about losing count past 20. I could see me getting to 75, having someone come in to say something to me and forget where I was

I sure don't intend to reduce the joy of re-winding but several people read these posts. I feel a bit obligated to try and define the boundaries of an arm, to make readers aware that there's a lot more to a good arm than wire size and number of turns. Perhaps the reason most active racers are glad the arms are factory-wound.

I wouldn't have taken your post that way at all. It may just be a matter of perception at this point... but it seems like lots more people were brewing-up hot winds in the old days (mostly out of necessity since even when you could buy custom-wound arms they were expensive). So here's this whole "retro" thing going on and what could be more "retro" than winding your own arms? Truthfully... even when the occasional "smoker" turned-up, it was all part of the fun. Now, with say a modern C-can, we have a hugely better platform to put these things in and really see what they can do. I'm thinking seriously of dropping to #23.5, #23, #22.5, or maybe even #22awg for an arm or two. What's the worst that could happen?

[Prof. Fate]

Hi John

I am not sure how to relate to the people I know who only think about legal class racing. Racing is pretty low on the scale of things I am interested in. Like a lot of us on the board, I have done my stint in G7... even in the day when you DID build the arm. There is just no venue, locally, where the racing involves interesting cars. The locals run fairly stock classic.

When I travel to BP or Denver, my primary drive is associating with my friends with a little mix of slot cars in there (and model airplane flying like Lee). But in neither venue do I really worry about the competition.

I do have a lot of my OLD "serious" cars. Run them for fun, which means I still am forced to build motors to keep them running.

I admit that I sometimes play jokes. That is, I have a car with a "P" can that, ostensibly has a "Group 12" arm in it. It is sort of a test of your motor "creds". If you notice it is too SHORT for that to actually BE a G12 arm, you get a grin from me.

For me, the bench time is golden. Racing is just a sideline result of having cars.

Fate

[havlicek]

Hi Rocky,

Then I guess we're birds of a feather... although I do see the benefit in proscribed forms of racing. There does after all need to be some sort of a level playing field. I also "get" just wanting to "build them and run them"!

Rick...if you see this, I got the balancer today and it's a real joy. The "extra" is a great thing as well and works like a charm. Rick made a removeable point that can be slid onto the end of the arm so that you no longer have to grind a point onto the arm itself... now that's using the old noggin!

Here's the best part, I tested three different arms I had balanced as best I could on razor blades and on every one, the R-Geo balancer consistently still picked-up a heavy side. It's noticeably more accurate than razor blades... so the arms will take a little step up in smoothness... THANKS, RICK.

[Cheater]

What's the worst that could happen?

The worst? The arm could explode when you zing it up to high RPM and embed pieces of shrapnel in your hands, face, and eyes...

John, I think what Don was trying to say is that the winds you are using are pretty extreme. Motors with these arms are going to need a lot of power, if you plan to run them, and they're likely to get very, very hot.

That doesn't in any way mean you shouldn't play with them if you want to do so. I believe Don just wanted to suggest that those sort of winds would not be the best ones to use for running on a home or a smaller track. He was just sorta waving a flag to inform newbies and others unfamiliar with slot car motors that the winds you are using are fairly wild and would likely be way too much for many of the venues where they might be run.

[Hworth08]

Truthfully... even when the occasional "smoker" turned-up, it was all part of the fun. Now, with say a modern C-can, we have a hugely better platform to put these things in and really see what they can do. I'm thinking seriously of dropping to #23.5, #23, #22.5, or maybe even #22awg for an arm or two. What's the worst that could happen?

Hi again John,

Well, true enough the worst that could happen is not much from a cost standpoint. But, 20 turns of 22 is getting close to G7 motors, and a fair amount less resistance than a G27 motor.

Under racing conditions they use aluminum endbells and Cobalt magnets along with strap cans to keep these hot winds together.

It's probably correct that the total magnetic field of today's C-can has improved quite a bit from the mid-'70s dot magnet era but I wonder if such "hot" arms can be supported by less that Cobalt magnets?

Some of you early '70s racers help out. How hot did the winds get before Cobalts?

[Pablo]

I tried to warn him, he is a speed demon and LOVES that household wire:

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

John, don't worry about being corrected in a "how-to". Just give a disclaimer "this is the way I did it..."

I have a special way I like to do mine; the comm always gets in my way, so I wind a pole, tag the end of the wire with a piece of masking tape "p1", a tiny spot of Krazy glue to hold it to the other windings, tag a new piece of wire "p2", leave some standing end and wind away, etc. until I have all the windings on, and marked. THEN I install the comm. That's just the way I like to do it. Others have their methods, too. It's all good.

[havlicek]

OK then, Pablo... I'll get something together in the next couple of days. Your method sounds like too much work to me though!

[Hworth08]

HERE'S is a thread from OWH that might be helpful for choosing winds. A thread that a person should strive to understand if their goal is to become a complete racer.

The thread is four pages and I feel it's not nice to link too much from a site that might be considered a "competitor". Excellent info though from a couple of slot racing masters.

[Cheater]

Don, we have no problem with links to other sites, as long as they're not porn sites...

[The Bugman]

And whats wrong with PORN SITES??

[Cheater]

Not gonna answer, except to say not linked from Slotblog...

[Hworth08]

And whats wrong with PORN SITES??

Well, after watching Victoria's Secret show last night I believe the majority here might prefer just looking at arms? It was pretty exciting though, sorta made me wish I was 23 again! After an hour I was glad I'm 53. After another ten minutes of the Andy Griffin show I was back to normal.

The re-winders might want to look HERE for info on modern arms to make comparisions.

[havlicek]

The worst? The arm could explode when you zing it up to high RPM and embed pieces of shrapnel in your hands, face, and eyes...

John, I think what Don was trying to say is that the winds you are using are pretty extreme. Motors with these arms are going to need a lot of power, if you plan to run them, and they're likely to get very, very hot.

Hi Cheater,

Well, when I asked the question it was sorta tongue in cheek. I mean if asked the same question about using a torch to build a chassis... the worst that could happen is a gas explosion ... or getting acid flux in your eye. Playing with hot winds is MUCH safer than handling compressed butane and acid... or spinning cutting tools (a chunk of a cutoff wheel thrown from a Dremel turning at 25,000 RPM makes a pretty significant projectile!). Point taken though. Since I've been going through a "pushing the limits" thing here to see what's what, it doesn't serve any purpose to wind puppy-dog motors just to see if they spin. I think a valid way of getting to a consistent level of performance is to try and get close to the edge and then back away some. People do need to use common sense with all this stuff and I think that should be a given!

[JimR]

Just as an aside -

Where does one find this R-Geo balancer that's been mentioned?
Is there a website to go to?

[havlicek]

They're made by Rick right here... just PM him. He makes all kinds of parts and tools (I also got the winder from him) that are priced right and work! In the case of the balancer, there are a few things that make it attractive:

1) It's extremely simple yet works.
2) There are no razor blades to mess with... that alone is a plus.
3) Instead of referencing the sides of the armature shaft (where even an imperceptible amount of runout could affect what you're seeing)... the magnetic balancer is actually referencing the end of the shaft (a single contact point).
4) There's no need to have the two razor blades exactly level to avoid the armature running off them. With a single contact point at one end of the armature... you could balance the arm with it upside down (if you chose to do that for some reason).

After playing some with the balancer, it does appear that the point needs to be pretty accurately concentric with the arm shaft to get the best results. It's not super-critical, but it does matter somewhat. Static balancing (on either razor blades or with the magnetic balancer) can be sufficiently accurate to get an arm spinning smooth. It's not as accurate as dynamic balancing... but it's easily doable right at home and can produce good results.

[havlicek]

OK... so here's a little run-down on how I do this stuff. Please note that this is only "my method"... and not necessarily the "correct method"... or the "best method". I fully expect Pablo and others here who are doing their own winds to chime-in and tell me where I'm being dumb-sloppy-lazy... whatever. I'll be illustrating what I do using a blank Mura C-can arm. These are really nice arms for a bunch of reasons, but you can do this with any blank... or by rewinding a factory arm after removing the wire and cleaning things up.

As you can see, the arm comes with a factory powder coat. This will prevent rust as well as provide some short protection where the wire is wrapped over the sharp edges of the end stack plates. I also add a couple of coats of nail polish right where the wire will wrap the stack but not out towards the ends where the spoxy will need to bond the wire to the stack. Also... you can see some overspray on the comm end of the stack. Some of this can be removed by carefully sanding or scraping it off, but I purposely leave a bit on there. It helps the comm to fit snugly until you want to fix it permanently. That way you can adjust both the overall length of the comm and the stack combined... as well as the timing of the comm and not have either moving around. Once both are set... a tiny drop of crazy glue will hold things together while working on it.



Next, I want to set up the arm to a known good size for my application. In this case the arm is going into a Mura can... so I match the overall length to that of a Mura arm. I usually use 1.100" as my max... the Mura being 1.098". That leaves me just enough for a washer at either end of the arm and maybe a second at one end. If you messed-up here by having the arm too long... you could always carefully trim some of the end spacer attached to the arm. As a matter of convenience (and since I don't have a timing protractor), I set the comm tab for a particular pole to be even with the following pole's leading edge. I do this step by eye, but you could also use a small straight edge or even build some sort of a simple jig that would lay against the comm tab and the pole piece's edge. They tell me this is roughly "high timing"... works for me.



The last thing I do to prepare the arm for winding (and actually... I do this before I mount the comm to avoid damaging it), is to polish it down to get rid of the powder coat on the outside. I take some #320, #400, #500, and #600 wet dry paper and lay it on my work-surface glass. I chuck the arm in the Dremel tool and start off with the heaviest... working to the #600 by running the arm across the paper at a slow speed with light to medium pressure. The dark color of the wet/dry paper makes it easy to see if you're applying even pressure across the whole arm so as not to slightly "lopside" the thing. There's a little "feel" involved here, but for such a low-tech method I haven't had any bad results. The #600 I use in my hand with the arm spinning and working with the paper on the rotation side where it won't get "grabbed" by the spinning arm... just lightly and carefully touching the arm until it shines. After all this, very little actual material has been removed from the arm. I finish-up by polishing the arm with a chromium-based polishing compound (made by Dico) since softer compounds pretty much don't do anything to steel.

... next up: the winding.

[havlicek]

Here's all the stuff to ruin a perfectly good armature:

1) Of course... the R-Geo winder from Rick.
2) Magnet wire... here it's #24 awg and of a type where the insulation is good for higher temps.
3) An X-Acto knife for scraping the insulation from the wire where it crosses the comm tabs.
4) A bit of silver solder for soldering the wire to the tabs and a small soldering iron off camera.
5) A plastic electronics probe for pushing the wire around on the arm without damaging it (a dull pencil works great, too).
6) A "precision file" set and holder for carefully notching the solder on the com tabs so the Kevlar won't slip off when tying it up



... And it's off to the races. First pole is wound... trying to be as neat as possible. Note the blue (for clarity) nail polish on the top (and bottom) of the arm to add a bit of short-circuit protection where the wire passes over the sharp edges of the arms end laminations/plates. You can also more clearly see the position of the comm tab relative to the arm's pole piece. Also, when working off a spool of magnet wire, it's best to lay the spool on the work surface rather than have it standing on end. It's a little bit of a pain because the spool will roll-around as you pull wire off it... but the wire won't kink as it would standing up and coming off the spool in coils.