26 replies to this topic

[aquavelvis]

There was a recommendation from a very credible source on a YouTube post that #42 drill blanks from Grainger would be fine 3/32 axles for slot cars. It's enticing to me because they're only $1.78 each if ordered in sets of 12. 

 

Grainger has two types of #42s: "drill blanks" and "reamer blanks"

 

Does anyone here have experience with these, and if so, is there a lick of difference between the two types as far as suitability for slot cars goes? Any concerns?

 

Thanks, and I hope you have/had a safe and nice Thanksgiving.

[MSwiss]

Guys who use industrial drill blanks, usually eventually snap them.

 

Stick with Koford axles.

 

They are the correct diameter and temper for slot racing.

 

In a real bad wreck, they will bend a bit, before they will snap.

 

IOW, letting you finish a heat, and being able to replace it between heats.

[Rotorranch]

       

 

What Mike said!!!

 

I bought drill rod from an industrial supply place in the middle/late '70's, and it's almost as soft as piano wire. Not good for axles.

 

Rotor

[MSwiss]

In the case of your typical drill blank, they are not designed for a side load, and are too brittle.

[Ralph Thorne]

       

 

What Mike said!!!

 

I bought drill rod from an industrial supply place in the middle/late '70's, and it's almost as soft as piano wire. Not good for axles.

 

Rotor

 

Drill Rod and Drill Blanks are two different things, drill rod is fully annealed and much softer.

 

A #42 drill blank is the way to go IMO and that's what most top racer's I know use. I've never snapped one personally plus I never have to worry if my axle is bent or not. However Kofords are obviously a very popular option also, both at a similar price point, try both and see what works best for you.

[Ecurie Martini]

It depends......I have used 3/32" drill blanks for years on my 1/32 cars without any problems - but - mine come from McMaster Carr and are offered in a range of hardness, finish and over/under sizes as well. Prices can range from $3 - $20+ /ft.  Hardness spec needs will depend on application - I use ball bearing in many of my builds so wear is not an issue.

 

EM

[aquavelvis]

All  good points. Thanks everyone

[Ralph Thorne]

It depends......I have used 3/32" drill blanks for years on my 1/32 cars without any problems - but - mine come from McMaster Carr and are offered in a range of hardness, finish and over/under sizes as well. Prices can range from $3 - $20+ /ft.  Hardness spec needs will depend on application - I use ball bearing in many of my builds so wear is not an issue.

 

EM

 

The OP referenced drill blanks from places like Grainger and McMaster Carr, the correct ones are #42's not 3/32". They come pre-cut to the correct length of 2 1/4" that we use in 1/24th racing, to one hardness and there is only a .0001" tolerance.

[swodem]

Are you using bushings or bearings?

 

I find the drill blanks are not smooth enough for bushing use and wear bushings out faster, therefore require more frequent oil application

[Ralph Thorne]

Are you using bushings or bearings?
 
I find the drill blanks are not smooth enough for bushing use and wear bushings out faster, therefore require more frequent oil application

I use them with our RTR adjustable bushings mainly. We just ran a flat track enduro a few weeks ago, 32 six minute heats, oiling once a heat with no smoothness or wear issues at the end of the race.

[bbr]

Like koford, the ends are chamfered nicely

[Bryan Warmack]

  The main difference between quality 3/32 axles and the #42 drill blank axles is a slight size difference. The 3/32 axles are .0938 diameter and the #42's are slightly smaller at .0935.

   If you ever have any trouble getting a 3/32 axle into some of the cheaper ball bearings, try the #42 drill blanks from McMaster Carr or Grainger.

[MSwiss]

Bryan,
So you put in the tight BB's, compensate with a slightly undersize axle, and then your axle gear and rear tires are a slightly sloppy fit?

This thread seems like a lot of goofing around, just not to give your local raceway, 91 cents more, for a slot car axle, or a few bucks more, for a $4.95 pair of BB's, that has been checked on a slot car axle, to make sure it's the right size.

[Eddie Fleming]

I like the Koford axles but they are a little short of what I would like in wide cars. I try to fill the axle hole in the wheels but with JK hubs on a wide car the Koford axle is a little short.

 

Not a problem I know but one of my idiot syncroce things.

[MSwiss]

No extra length (or weight) on them, for sure.

They do make you center them , if you want the same axle penetration, in both wheels.

IMO, not a big deal, and much easier than getting a great gear mesh.

Stu's 1/8" axle is real long, and always needs to be shortened if used for a rear axle.

[old & gray]

Bryan,
So you put in the tight BB's, compensate with a slightly undersize axle, and then your axle gear and rear tires are a slightly sloppy fit?

This thread seems like a lot of goofing around, just not to give your local raceway, 91 cents more, for a slot car axle, or a few bucks more, for a $4.95 pair of BB's, that has been checked on a slot car axle, to make sure it's the right size.

 

In the aerospace industry we refer to this as "value added".

 

(I find they work just fine Mike, bought them at my local raceway.)

[Ecurie Martini]

 

The OP referenced drill blanks from places like Grainger and McMaster Carr, the correct ones are #42's not 3/32". They come pre-cut to the correct length of 2 1/4" that we use in 1/24th racing, to one hardness and there is only a .0001" tolerance.

 

 

Bryan,
So you put in the tight BB's, compensate with a slightly undersize axle, and then your axle gear and rear tires are a slightly sloppy fit?

This thread seems like a lot of goofing around, just not to give your local raceway, 91 cents more, for a slot car axle, or a few bucks more, for a $4.95 pair of BB's, that has been checked on a slot car axle, to make sure it's the right size.

 

 

Grainger and McMaster are very different in the range and specs of offerings

 

It's not an issue of avoiding a local raceway - to the best of my knowledge, there are none within 100 miles of me and the commercial track is not my scene.

 

I specifically referenced 1/32 cars.  In that world there are variations in bore spec for both gears and wheels.  I assume it's a ploy to encourage same source mating of parts.  I routinely use 3/32" axles and, when needed, a 3/32" reamer to achieve a good fit.  When I use oilite bushings, I counterbore them for about half their depth to 1/8".  The typical stock bushing size is overkill for the loads in the smaller cars.

[MSwiss]

Alan,
I was addressing the OP.

Since Slotblog is commercial raceway oriented, I don't expect basement racers to support commercial raceways.

My comment was just a light-hearted reminder, and part of adhering to the hippocratic oath, of people like myself, who pay rent, to provide a place for people to race.

If I was mad, I would of referenced the fictional McMaster Carr and Grainger Raceways. Lol

[bbr]

I tend to use the best product I can find.
Sometimes they are pricey, but you get what you pay for.
I use koford axles bc it is a product designed for slot racing and I used it in all my different types of cars. And I used the German bbs which are the best as far as I know, install them in once and forget about them. Yes they are pricey also. Do they perform any better? Maybe,,,,, but I know that they will not fail.
With the koford axles, it is a consistent product, it just works for all my applications.

[Ecurie Martini]

Alan,

Since Slotblog is commercial raceway oriented, I don't expect basement racers to support commercial raceways.
 

 

I understand that and visit Slotblog with that in mind because I find the technology both interesting (and sometimes inspirational) even though my participation in the hobby operates under a different set of constraints. Basic engineering principles apply no matter the size.  My involvement in the hobby predated the advent of commercial raceways and associated suppliers and I have always cast a wide net for components and materials.  Occasionally I am moved to share some of what I think I have learned.

[philk]

I like the Koford axles but they are a little short of what I would like in wide cars. I try to fill the axle hole in the wheels but with JK hubs on a wide car the Koford axle is a little short.
 
Not a problem I know but one of my idiot syncroce things.

. Same with the Alpha hubs. Would like them just a bit longer. But like Mike said it really hasnt been a problem .

[MSwiss]

Eddie, Phil,

A visual on why the length isn't a problem.

[Rotorranch]

Some builders prefer an axle that goes all the way through the wheel hub. So far, I haven't had any problem with it, but I have not raced since the virus struck.

 

Rotor

[Eddie Fleming]

Mike I said when I brought it up it is not a problem but I would like them a bit longer.

 

If that much axle weight is my big problem I am in fine shape.

[Pablo]

Weight isn't really the issue, it's excess rotating mass. And it's high up.

Koford axles are the gold standard for racing, end of story.

 

I'm sure Ralph Thorne Racing drill blanks are nice as well, otherwise he wouldn't sell them.