50 replies to this topic

[Pablo]

The inside diameters on these Parma 10 thou steel spacers (on the left) aren't quite big enough for me. OD is about .312".


 
They won't go all the way to the bottom of the post on any flag I try, both threaded and unthreaded, vintage and modern.

The 10 thou spacer on the right is about half a thou bigger ID, about .350" OD, and they fit perfect.


But I'm not sure what brand they are and I need more. I think they are Slick 7. Can someone please confirm that?

Thanks,

Pablo

[Duffy]

"Half a thou" difference and you're clearing the boss fillet radius on the guide? Are you freakin' kiddin' me here? You must have more than that, you could seat that interference with a steely-eyed glare.
 
I've seen cut-down guides with a mismatch in the boss where the material was milled away, and it took hand-trimming the boss with an X-Acto blade; but you clean the fuzz and milling marks off the face at the same time.

If it's really just the boss fillet, a quick chamfering swipe around the ID of the bottom washer with your Dremel should solve the prollem.

[Pablo]

No, I am not kidding you.
 
I have no idea what a boss fillet radius is, sorry. All I know is, these spacers don't fit right. I tried them on about 10 different flags of all types, and they were not able to sit flat at the base of the post on a single one of them.
 
I blueprint all my flags using a sanding block, emery board, two different threaders, and a Magnehone facing tool. This ain't operator error. It's a spacer problem, not a Pablo problem.
 
I tried filing, Dremeling, praying, and it's all a goat rodeo.

[Eddie Fleming]

"Goat rodeo" 
 
How about the Koford brass or are they copper spacers?

[Duffy]

Okay, hey listen, Pablo, I wasn't implying it's "your" problem, I was trying to figure out what might be going on. I can't see .0005"ø resulting in that marked a difference, and there wasn't enough data to parse in your original post. Still isn't, because we haven't seen a clear reason to point to for what you're seeing.
 
A fillet is that little corner-round between the post and the guide's face, that flat part the washer bears against: that teeny roundness between the cylindrical boss and the flat surface. You need that, particularly in the injection-molding of the guide, to prevent cracking right at the corner as a result of uneven cooling in the part after molding - the surface will cool and shrink faster than the inside, and the plastic will cope with that by cracking along any sharp corner. So you make a fillet, so the radiused surface will "pull" and resist the cracking.

[Pablo]

Thanks, Duf, but my wish is merely for someone to confirm the spacers on the right side in my photo are Slick 7, or what.

Not to bash Parma spacers, they simply don't fit my flags. I shouldn't have to force the spacer down to go flush with the rotating surface.
 
"But I'm not sure what brand they are and I need more. I think they are Slick 7. Can someone please confirm that?
 
Surely someone has a 10 thou steel Slick 7 spacer, please mike the OD and see if it's about .350".

[CoastalAngler1]

Here you go, Pablo, hope this helps you from getting spaced out.  
 
All these are .010" guide spacers. Koford on left, Slick 7 in center, and Parma on right...
 
The Parma cut-down guide pictured has the Slick 7 spacer - notice the Koford OD will fit. The Parma spacers are tight and need mods that are goat herding opportunities for hobbyists that got the time. I gotta remember to share those Parma spacers with racers that need to borrow one - hahahaha.
 

[Gator Bob]

I'm not sure what's going on here...

 

The ID is too small and it keeps the spacer from 'going down' and seating on at the base of the post or the OD is keeping the spacer from seating?

 

The 5 different brand .010 spacers I measured ... don't now the brand .. the OD range is from .314 to .394   

[Pablo]

Bingo, thanks Charlie. They are Slick 7's, that's what I thought but wanted to be sure.

(Note to self: don't borrow flag spacers from Charlie )

 

Bob, the only reason I mentioned OD's is for identification purposes. OD isn't the issue.

 

I'm good to go. Thanks everybody

[MSwiss]

Go with Koford .010" phos bronze and your worries are over.

They are manufactured as guide washers, not some existing hardware part.

[Bill from NH]

Note to self: "Don't buy any Parma steel guide spacers, or the Chinese win again."

Fortunately I still have guide spacers from Parma & REHCO in the 70's.

[Gator Bob]

I see some guys running cut down flags and a stack of spacers.

[Pablo]

Maybe I should have posted this in my OP.   Sorry.

Parma's spacers won't even fit their own flags - this is as far down as they go, then stop.


 
Even when the post is threaded to the hilt, they still won't go all the way down.

[MSwiss]

I bet they fit their white guides fine.

Since 1961, every slot car part has fitted perfect until Parma broke the 55 year streak with these "guide washers from Hell". LOL.

PS: Maybe they were meant for Mike Fleming.

[Gator Bob]

"guide washers from Hell".

 
China... but not far off.

[Pablo]

Matter of fact, they do fit the white flag perfect, Mike. Wow.

 

What is the difference between the standard black "The Blade" and the white ones?

[MSwiss]

The black ones have a bigger shaft.

[Pablo]

I figured that one out all by myself, Mike.

[Ramcatlarry]

Curious issue... 3/16" is 0.1875",  5mm is larger at 0.195"+/- and should not be an issue. What supplier screwed Parma with undersize product? ... And no one else caught it in QC?

[Duffy]

Another non-washer-related bit of data involves the potential diametral difference between the molded threads up top and your chased threads near the guide's flange. Most of our dies are made by just tapping the die tube with a 10-32 tap and grinding some sort of chip clearance in, which makes a passable tool but not a great one. Depending on the class fit (the clearance between screw and nut) that the tap's meant to cut, you can have a die that cuts a .189ø thread. Add to that, the lack of back clearance in the "die" means that part of the plastic in the engaged area isn't cutting but just getting pushed under the die, and will spring back out when it can. Your result in all this will be that you may have interference on any washer with much less than a 5mm hole.
 
EDIT: Larry chimed in while I was blathering - you should keep in mind, a 10-32 thread is not nominally 3/16"ø, it's .190"ø - and for the reasons I outlined above, you may very well need to go a skosh bigger in the rest of your gear from that. Your guide tongue will probably pass a #11 (.191"ø) drill. Check it out.

[John Miller]

The black ones have a bigger shaft.

Keep it PC please.

[Pablo]

Another non-washer-related bit of data involves the potential diametral difference between the molded threads up top and your chased threads near the guide's flange. Most of our dies are made by just tapping the die tube with a 10-32 tap and grinding some sort of chip clearance in, which makes a passable tool but not a great one. Depending on the class fit (the clearance between screw and nut) that the tap's meant to cut, you can have a die that cuts a .189ø thread. Add to that, the lack of back clearance in the "die" means that part of the plastic in the engaged area isn't cutting but just getting pushed under the die, and will spring back out when it can. Your result in all this will be that you may have interference on any washer with much less than a 5mm hole.

 
I won't pretend to fully understand all that, Duffmaster. But I have a feeling you just explained why, after I carefully and fully cut threads on a new flag with my Cahoza threader, I still need to run a Magnehone tool over the first few threads to make the nut start perfectly straight. Yes? 
 
(John Miller's avatar = "Troublemaker" )

[Pablo]

As long as we're on the subject of nuts n shafts n whatnot, who originally bought a bunch of Lowes plastic nuts that fit flag threads, colored them, and started selling 'em as slot car parts?

[Duffy]

... after I carefully and fully cut threads on a new flag with my Cahoza threader...

 
Dunno all that; maybe. I'm used to starting those nuts in the wrench, and even if they're a little stiff to start I've never cross-threaded one.
 
I was able to get a much better cut out of my die by grinding a rake into the straight flutes to improve the slicing angle. That, a good bit of oil, and backing off a full turn and recutting with every turn of advance helped me a lot.

[CoastalAngler1]

Man, does Duffy ever pit for anyone? That is some sweet info, now where is that potential diametral difference?  

 

I think Ramcat and Duffy are letting out some secrets. Sure wish whatever they're saying would keep the guide from deslotting.