Different kinds of mandrels

Signed-In Members Don't See This Ad

jbg230

Member
Joined
Jun 13, 2016
Messages
95
Location
Kansas City
Definitely still a beginner since I don’t even know why there’s A, B and C mandrels. Maybe there’s even more than that, but what is the reason one would use mandrel A vs. mandrel B?
 
Signed-In Members Don't See This Ad

monophoto

Member
Joined
Mar 13, 2010
Messages
1,878
Location
Saratoga Springs, NY
You need a B mandrel if you a using a kit designed around a B mandrel.

Ultimately, the difference between A and B is the diameter of the shaft. An A mandrel is 1/4" in diameter; B is slightly larger.

Some suppliers sell only kits designed around A mandrels, while other suppliers offer a choice of kits that require different mandrel sizes. AFAIK, there is never a choice of A versus B in the same pen kit - its just that some kits are designed for use with larger mandrels.

So that begs the question - why are some kits designed for use with larger mandrels? I suspect that the answer has to do with the fact that some kit manufacturers (in Taiwan or China) design around one size, while others design around the other size, and for no reason other than that's the way they have always done it.
 

ed4copies

Local Chapter Manager
Joined
Mar 25, 2005
Messages
24,105
Location
Racine, WI, USA.
The B mandrel was introduced many years ago by Berea. For a while they made kits that used that "beefier" mandrel, the Churchill and Cambridge among others. The mandrel never caught on, so now you can get "A" size bushings for those kits. So, presently there is no real reason for a B mandrel and I have never heard of a C mandrel.

Ed
 

jbg230

Member
Joined
Jun 13, 2016
Messages
95
Location
Kansas City
Thank you for those replies. Always good to learn more about pen turning. Nice to know that I don't have to buy another "thing" today. Tomorrow of course will be another matter.
 

Rodney W

Member
Joined
Feb 27, 2019
Messages
12
Location
Centralia, WA, USA
The B mandrel was introduced many years ago by Berea. For a while they made kits that used that "beefier" mandrel, the Churchill and Cambridge among others. The mandrel never caught on, so now you can get "A" size bushings for those kits. So, presently there is no real reason for a B mandrel and I have never heard of a C mandrel.

Ed
Does this mean one size mandrel will work for every kit? It was looking like every supplier had their own mandrel and bushings.
(I've been interested in pen making for a few years but the lathe I've been using is a 1940's vintage entry level model that doesn't accept a lot of newer accessories. I just bought a 1960s Craftsman that will take MT1 accessories so I can start gearing up for pens now.)
 

KMCloonan

Member
Joined
Jun 13, 2017
Messages
127
Location
Fox Lake, Illinois
I have been avoiding the whole mandrel size issue by turning between centers, and then using my A mandrel with a mandrel saver and some plastic cones to hold the blanks for finishing..
 

monophoto

Member
Joined
Mar 13, 2010
Messages
1,878
Location
Saratoga Springs, NY
Does this mean one size mandrel will work for every kit? It was looking like every supplier had their own mandrel and bushings.
(I've been interested in pen making for a few years but the lathe I've been using is a 1940's vintage entry level model that doesn't accept a lot of newer accessories. I just bought a 1960s Craftsman that will take MT1 accessories so I can start gearing up for pens now.)
Yes and no - most kits are designed to use the so-called 'A' mandrel (which is 1/4" in diameter). But as Ed noted, one kit vendor (Berea Hardwoods) introduced a line of kits that used a larger mandrel (the so-called 'B' mandrel). However, that was unique to kits sold by Berea, and no other kit suppliers jumped on board with the idea and it never gained much popularity. So as a practical matter, most kits today can be done using the ubiquitous 'A' mandrel. Must pen turners prefer the simplicity of using only one mandrel (and actually, many pen turners have shifted away from mandrels altogether in favor of turning between centers.

MT2 is larger than MT1. You can purchase both MT2 and MT1 mandrels, but MT2 are far more common simply because MT1 is semi-obsolete - most modern midi- and full-size lathes are MT2. There are still a few mini-lathes in MT1, but I suspect that they will fade away over time.

However, you have a lathe that is MT1, so the obvious choice for you is to get a compatible mandrel. If you stick with the hobby, you may eventually upgrade to an MT2 lathe, and at that point you will have a choice - either get rid of the MT1 mandrel and purchase a new MT2 mandrel, or purchase an adapter that allows you to use your MT1 mandrel in a lathe with an MT2 headstock. One supplier is Little Machine Shop. An adapter is less expensive than replacing the mandrel. On the other hand, if you stay with the MT1 long enough, you may conclude that you owe yourself a new mandrel when you upgrade to a new (larger) lathe. Choices - - -

People argue about whether adapters are a good idea (actually, there are many things that turners argue about - its part of the fun) - the potential problem is that any time you add things to a rotating shaft, you increase the risk of 'runout' (the fancy word that means 'wobble'). Practically, however, adapters that allow smaller male tapers to be used with larger female spindle tapers generally don't present much risk of runout, so an adapter that marries an MT2 spindle with an MT1 mandrel taper is usually not a problem. That's because the adapter is simply a sleeve that fits over the smaller MT1 mandrel so that it can slip into an MT2 tapered spindle. Going the other direction is more of a problem.
 
Top Bottom