Engineering input to Morse Tapers

[MBfreak]

I tend to want to understand how things actually work.
For the moment I have latched onto the processes that makes Morse-Tapers develop the holding power between male/female parts.
I have a general idea. But not at ease with that, simplified understanding is so often wrong.
Have looked after deeper explanations in English, German and Swedish but have found dimensional tables only.
I know there are a number of very knowledgeable people here. Any deeper info or links to Morse Tapers would be most welcome.
Believe me or not, I can wake up at four in the morning thinking about MT.

Best regards

Ola

 

[Zeke]

It is simple, no need to over think it. Just a friction or interference fit.

 

[zkling]

Look up "machine taper".

 

[Ign]

Yeah, someone figured out if you wedge one taper into another the holding power is incredible.

They started out with "local" standards and slowly things became universal. In the process some were abandoned and others were widely adopted, which is why there seems to be little rhyme or reason from one size to the next, or why they start and end at generally random dimensions.

 

[larry_g]

http://www.practicalmachinist.com/vb/general-archive/ot-theory-self-holding-taper-79627/

I did a search on 'self locking tapers' and the above came up. Start with self locking tapers and a lot of information related to the machining industry will come up. Please don't restrict yourself to Morse tapers. There are lots of other tapers out there that should deserve just as much worry.

lg
no neat sig line

 

[kazlx]

Like Zeke said, it's nothing magical. Two machined surfaces have quite a bit of friction again rotation set up like that in a male/female matching taper. The pressure from the drill bit or other tool helps secure the taper even more, but it doesn't take much to release it with a drift or poke from behind with a tail stock on a lathe. Bigger tapers have more surface area and more holding power.

 

[HoosierBuddy]

FYI...I haven't tried this myself, but I was told by an "old timer" that when a morse taper slips, you can drastically increase the holding power by putting chalk on the male taper before inserting.

Might be helpful for some situations with a lathe.

Phil

 

[kazlx]

You also have to make sure they are super clean. Even tiny chips or junk on there can cause issues. You lose all the surface area if it doesn't seat all the way in there.

 

[leg17]

I tend to want to understand how things actually work. For the moment I have latched onto the processes that makes Morse-Tapers develop the holding power between male/female parts.
Believe me or not, I can wake up at four in the morning thinking about MT.
Best regards
Ola

Locking tapers depend on the coefficient of friction of steel.
Smaller tapers are "locking" and larger tapers are "self-releasing".

Here is a link showing the basics.

https://books.google.com/books?id=O...coefficient of friction locking taper&f=false

A number of makers had different schemes to settle on standardization of tapers, but the Locking/Self-releasing issue is pure math.

Good question.

 

[MBfreak]

Leg 17.
Thanks a lot for the enclosed info.
The most relevant info so far.
And for those who thinks it is "simple", my personal view is that as long as it is not shown in a convincing, physical, mathematical way how it works, " simple " is just an easy way out of the subject.
But , that is me. Many years in engineering has humbled me.

Best regards,

Ola

 

[nine4gmc]

Good question and great replies! Thanks for posting!

 

[larry_g]

http://www.calqlata.com/productpages/00041-help.html

Another good bit of info

lg
no neat sig line

 

[MBfreak]

lg
Read your attachments.
Some of the info there is at best VERY marginal when it comes to taper fits as in the practical machining apps.
Van De rWaals molecular attraction requires extremely fine surfaces and an " absolute" finish. Even then, it is a weak force.

The JOblocks , invented less than 30 kms from where I live, relied on three factors to stick together.
Super finish, ie Vand Der Waal
Air pressure, since the parts fitted well enough to expel air.
Two oil films ( of molecular thickness) binding together.
None of this is going to help much in ie a Morse Taper.

I am now more at ease. The friction and cos of the angles reasoning is to me a very credible explanation for most of the real world action of tapers. Will try to pus some figures in for my self and see if I can calculate the locking force.

Best regards

Ola