Quote: I think the die must have been at quite an angle when it did clash?
There's probably a very narrow range of tilt (on the z-axis) of the hammer die which could cause this - too little, and the clash will be closer together or even continuous. Too much, and the opposite side of the die will either hit something first (clash on the upper side of the tilt) or hit the low edge of the tilt (lower side clashing). I'm assuming - if this is a collar clash, not that anything else makes sense at the moment - the clash would more likely happen on the lower side of the tilt than the upper, although that seems possible as well. The lower side would allow more tilt latitude, making the clash more possible.
What I wouldn't give for accurate engineering drawings of how these presses are put together, and high-res images of an actual die. I've been looking for the latter for a while without success, aside one Commem.
To illustrate, a die that was tilted enough and banged into a collar could pick up the circular lines from the collar if positioned something like in the image below. This is an actual die that I placed in a tilted position over a collar.
Of course the collar could be what is titled to the same effect.
Click on the image to enlarge.
Die and Collar from my collection of broken/defective minting tools.
My gut tells me the collar is more likely to tilt that much than the die. My visualization of the equipment (wish I had those drawings) says a fragment under the collar could do this, and a fast-moving setup guy would more easily miss that. Die alignment should be something approached like a Takeoff Checklist but the collar might fly under the radar.
I'm thinking more like Mike Diamond said. The planchet was damaged going into the collar. When the coin was struck it removed most of the arc of the line in the field areas, but not close to the devices. It it were on the die, then that full arc would be seen.
I stand corrected.
Ken Do you have an images on how the feeder fingers work?
I never said or implied it was planchet damage. I fully believe it is die damage. A tilted and slightly offset die or collar could create the short, slightly curved die dents that are seen on the obverse face. But I cannot be sure this is the cause.
You can see modern press equipped with a feeder here:
yHu4Aqn__1M
You'll see them at 2:25 into the video. It goes by fast so slow it down by about 50%.
Here is a dual feed feeder finger from about the late 1960s/1970s.
For those that care:
This is a top and bottom view of "Duel Feed - Feeder Fingers". These (and variations of this concept) saw use in the US Mint from about the late 1960s and into the 21st century where many have been phased out by high speed presses fixed with single die pairs and more sophisticated feeder/ejector systems.
The lead end of the fingers are the portion that ejects coins from a duel-die set up. You'll notice that one side of the lead end is straight and the other machined at about a 12 degree angle. The side that is angled is able to catch and shift coins from the die that is off set from to the right of other die and eject them both without incident (or not -- to the delight of error collectors). Study the two "holes" within to see the placement of the dies in relation to each other.
Improper feed and/or misshapen planchets are often the cause of feed-related errors such as Off Centers and Double Strikes.
Image courtesy of Marilyn Van Allen/Leroy Van Allen. From CONECA's Introduction To Mint Errors & Varieties PowerPoint Show.
Rackster, I have links to 124 videos on Minting and related. I really like the one below as it shows the Mint making the master die for the 1938 Jefferson nickel.
mBjD9N1APsw
*** Edited by Staff to add YouTube tags. Please use them in the future. We prefer embedded video. ***
Thanks for all the information in this post I now have been watching videos getting a complete understanding for hours now. Next I'm moving on to coops videos. This is education week for me a lot of good posts.
Hi Ken - I appreciate the link and the education! It's a real privilege when a few of you master tool men/numismatists come by the forums. Feels like an opportunity to meet and learn from a few Santa Claus'! Pretty exciting!
Tweak - I fully agree. It's been a great week for learning!
Disclaimer: While a tremendous amount of effort goes into ensuring the accuracy of the information contained in this site, Coin Community assumes no liability for errors. Copyright 2005 - 2026 Coin Community Family- all rights reserved worldwide. Use of any images or content on this website without prior written permission of Coin Community or the original lender is strictly prohibited. Contact Us | Advertise Here | Privacy Policy / Terms of Use
First Page
Posted 04/21/2015 8:37 pm
