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-   -   Pin drive bolts splitting Help Please (http://www.clubcobra.com/forums/all-cobra-talk/93788-pin-drive-bolts-splitting-help-please.html)

CNGreen 01-08-2009 04:18 PM

Now, see that? I been edumacated today!

:)

David Kirkham 01-08-2009 06:42 PM

Gents:

I am sorry to say, the education is about to continue.

When I measured the Trigo pins the first time, I just grabbed a simple protractor tool. They obviously did not have a 90 degree taper and 82 looked pretty close so I figured that is what it was.

Well, today I bused out the Mitutoyo angle gauge to check our pins as we made them...it wasn't pretty. Our pins are right on the money at 82 degrees, but I held the taper up to a Trigo taper and noticed it was slightly off...hmmm???

What gives?

Remeasured our pin...82 degrees. Remeasured the Trigo pin (this time with a proper angle gauge...76 degrees!!!!!!!

:mad::mad::mad:

Let's see. Standard tapers in machining. 60, 82, 90, 100 and 120 degrees. NO 76 ANYWHERE I have ever seen.

Oh well. I'll wait to see what the adapter is actually machined to and then we will fix the pins. No big deal, but irritating, none the less.

Perhaps, (and only perhaps) this is why some people have had problems with the pins. Perhaps the taper of the pin doesn't match the taper of the hub adapter. If the tapers don't match, you will have very high point loading on the parts, exceed the yield of the material, and have a galling fest. Galling could very well cause the pins to tip and cause all sorts of grief.

David
:eek::eek::eek:

ps. CNGreen
Better send me along the tracking number. Fed Ex didn't deliver today. :CRY:

Dominik 01-08-2009 10:13 PM

Hi David!

The taper on the exisiting pins are not machined, rather hammered on in a die. Probably the same time the internal hex is done.
That's why the taper is off, wrong angle, and not concentric. The thread is probably also chased in that die.

Please measure if the thread is concentric, or just let the Trigo pin run on a 1/2" stud in a drill press.

Let's measure adapters, and if they are NOT 90 deg, offer pin in 90 deg nevertheless.
People could taper them on a drill press using a standard 90 deg taper.

Of course, if we can confirm that they (and Superformance) share all the same angle, you could offer the pins drive nuts in that angle.

Dom

Rick Parker 01-09-2009 01:32 AM

Quote:

People could taper them on a drill press using a standard 90 deg taper.
We would be more inclined to use a lathe.

Dominik 01-09-2009 02:33 AM

Sorry, I meant the adapter.

Dom

CNGreen 01-09-2009 07:55 AM

David, I sent you a PM With the tracking url...

cdnus 01-09-2009 08:45 AM

I am definately not a machinist, so could someone splain what a "90deg. taper" is or looks like?

Thanks Craig

Rick Parker 01-09-2009 09:37 AM

I believe Dominik is attempting to describe an angle of 45 degrees on each side of the nut intersecting at an imaginary 90 degrees.

Dominik 01-09-2009 09:53 AM

Hi Craig!

I am engineer, but my first language is German. So my wording might not be the correct English. On a drawing you would actually get a 45 deg angle indicated for round material, resulting in 90 deg when you make it on a lathe (by turning it)

David posted a picture further up from his part. Have a look. I try to think of another example of a 90 deg tapered round material. A drill bit has 108 deg.

A pin-drive from a knock-off adapter, maybe ;-)

Or look at an ordinary wheel nut. They have an "angle" (taper, bevel) on the wheel side.

In our case, if the angle (or taper) from pin-drive and adapter are not the same, you create high forces on a small contact area. Worse, if that angle is not concentric, you create high forces on one side which will cause the pin to sit skew.

Then you can't get your wheel on. If you bend it straight, it will "relax" inside the wheel bend back and cause the wheel to stick.

Did that help?

Dom

Dominik 01-09-2009 09:54 AM

1 Attachment(s)
Thanks Rick, for helping me out here :-)
Picture shows 90deg tool to countersink holes into the adapter.

Dom

cdnus 01-09-2009 11:20 AM

Dominik
I guess it's all in the language used.
Here we would refer to that tool as a 45deg countersink. The taper on my vintage nuts I measure @ 60deg from the centerline, so you would refer to them as having a 120deg. taper? if I am understanding you correctly.
Also your english is much better than my non-existant german.

Thanks Craig

Larry N Johnson 01-09-2009 01:55 PM

Quote:

Originally Posted by cdnus (Post 911593)
Dominik
I guess it's all in the language used.
Here we would refer to that tool as a 45deg countersink. The taper on my vintage nuts I measure @ 60deg from the centerline, so you would refer to them as having a 120deg. taper? if I am understanding you correctly.
Also your english is much better than my non-existant german.

Thanks Craig

Yes, the Vintage pins are 60* as measured by David Kirkham yesterday.

CNGreen 01-09-2009 02:22 PM

Anybody want to start a thread about Fed-Ex delivery?? :mad:

Fed ex says they couldn't deliver yesterday due to weather.

So, how WAS the weather in Provo yesterday? Blinding snowstorm?

Anyway David, sorry for the delay! As of now status is still "on the truck".

:rolleyes:

Larry N Johnson 01-09-2009 02:50 PM

Quote:

Originally Posted by CNGreen (Post 911625)
Anybody want to start a thread about Fed-Ex delivery?? :mad:

Fed ex says they couldn't deliver yesterday due to weather.

So, how WAS the weather in Provo yesterday? Blinding snowstorm?

Anyway David, sorry for the delay! As of now status is still "on the truck".

:rolleyes:

The weather in Provo was fine; I drive there no problem. UPS delivered to Kirkham twice yesterday. Go figure.

David Kirkham 01-09-2009 03:05 PM

Quote:

Originally Posted by CNGreen (Post 911625)
Anybody want to start a thread about Fed-Ex delivery?? :mad:

Fed ex says they couldn't deliver yesterday due to weather.

So, how WAS the weather in Provo yesterday? Blinding snowstorm?

Anyway David, sorry for the delay! As of now status is still "on the truck".

:rolleyes:


Just arrived! I just unpacked the box. I guess FedEx drivers need to learn how to drive in the snow...hahahahah.

Frankly, this is the first time we have ever had a problem on an overnight shipment from any of them, UPS, USPS, FedEX. In 14 years, I wouldn't say that is too bad.

I am buried right now but I will measure them all up soon. I am dying to find out what is going on.

David
:):):)

David Kirkham 01-09-2009 03:06 PM

Quote:

Originally Posted by Larry N Johnson (Post 911620)
Yes, the Vintage pins are 60* as measured by David Kirkham yesterday.

Special thanks to Larry for all the help!

David
:):):)

strictlypersonl 01-09-2009 03:10 PM

Hmmm. I've got a set of Vintage adapters (don't know the "vintage") that have a 90 degree cup for the nut/pins.

Paul F 01-09-2009 07:21 PM

David,

Please also check the Compomotive pin I sent. Should have arrived today per UPS tracking.

David Kirkham 01-09-2009 07:41 PM

Gents:

I took a lot of pictures today and found a lot of very interesting things out. I will post more pictures later of what I found. I don't think what I found will make a lot of you happy campers.

The Trigo pins I have here have a 76-79 degree taper on them.

Today I received a Trigo pin from CNGreen. It has a 79 degree taper on it.

I received a pin from Paul F. today and it had a 76 degree taper on it.

I had several Trigo pins here in stock and they all had a 76 degree taper on them.

I then measured the HUB ADAPTER from CNGreen. It had a 90 degree taper on it. :eek:

I think we found why pins are loosening up and doing who knows all not-so-nice things.

I will post the autopsy report tomorrow.

David
:(:(:(

David Kirkham 01-09-2009 07:52 PM

On a final note for tonight, there has been some confusion on this thread as to how angles are measured in champhers, counterbores or countersinks. In every country that I know of, the angle of a countersink in a hole is measured by the total angle the cutter makes in the hole. In other words, you take a protractor and measure the angle the cutter makes on BOTH sides of the flutes. (Pictures will help...tomorrow).

Champers, on the other hand, are defined by 1/2 of the total angle. Therefore, a 45 degree champher makes a 90 degree countersunk hole. Champers are defined by degrees because you can make a 45 degree champer on the edge of a rectangular part--the other side of which can be on the other side of the casting, or not even there at all. On a hole, however, they measure both sides.

I know it can be confusing. I added a link to a countersink supplier. Notice the industrial standards (that are used all over the world, by the way).

60, 82, 90, 100, 120 degrees...76 degrees is not used anywhere I can find.

http://www1.mscdirect.com/CGI/NNPDFF...0&PMT4TP=*LTIP

David
:):):)


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