WHY THE TANG?

[Michael GilliganParticipant @michaelgilligan61133]

Time for a little review, I think

Shout if you think I have this wrong:

• The circular-section taper was a logical development from the square-section that was commonly used on drills in braces.
• It was devised to improve runout
• We have no clear indication of what degree of taper was originally used; and this may indeed be ‘various’…
• Screw threads and tangs were proposed as means of retention/drive/extraction
• Morse’s optimisation of a  self-holding taper was invented later

Therefore, there might well be no clear answer to the opening question … The use of tangs on Morse tapers being a matter of evolution

I personally will be much happier if I can see Samuel Colt’s patent

MichaelG.

Edited By Michael Gilligan on 20/09/2020 15:08:40

[HOWARDTParticipant @howardt]

When you consider the amount of tools and holders that are fitted directly to tapers with no other anti-rotation device, then why would a drill tang be considered an anti-rotation device as against a removal device. Drills can be had in all morse taper sizes and each size covers a standard drill range with some overlaps. When considering small drill diameters on a 1MT the drill will break long before the tang twists. I think the tang was an evolution created by some one in the past to overcome the problem of removing a taper that caused less damage then driving a wedge between the tool and the end of the spindle.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by HOWARDT on 20/09/2020 16:20:09:

When you consider the amount of tools and holders that are fitted directly to tapers with no other anti-rotation device, then why would a drill tang be considered an anti-rotation device as against a removal device. […]

.

Third, fourth and fifth bullet-points in my list above … plus the text quoted from patent 924,388

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

[for what it’s worth]

It appears that this machine is the subject of Colt’s patent: **LINK**

See also: **LINK**

https://parkplanning.nps.gov/showFile.cfm?projectID=14231&MIMEType=application%252Fpdf&filename=Chapter%202b%20Historical%20Overview%2Epdf&sfid=71403

… so the tang and taper arrangement may be a relatively minor component

The search continues

MichaelG.

.

Ref. **LINK**

https://archive.org/stream/patentsforinven04offigoog/patentsforinven04offigoog_djvu.txt

A.D. 1854, April 12.— N«861. 

COLT, Samuel. — " Improved machinery for cutting or shaping 
" metals." Shaping locks and parts of fire-arms. 

The Specification and drawings, which should be referred to, 
describe milling tools and screw-cutting machinery for shaping the 
various parts of gunlocks, &c. 

[Author]

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