whats the size of a A mandrel?
- Thread starter Jay_bobo
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its_virgil
Member
.24409
PSNCO
Member
7mm rod. It's the most common for bushings to slide onto
hilltopper46
Member
It's actually somewhat smaller than 7mm as 7mm is what we drill a hole for to put the brass tube into. Many are 0.246, but it varies by manufacturer.
its_virgil
Member
We call them 7mm but they actually measure close to 6.2mm which is .24409. We also say they are 1/4 inch or .250 but they are actually a little smaller. Not trying to argue but give accurate information…since you ask for the mandrel's measurement. If you are purchasing a new one then, yes, purchase a 7mm mandrel which is how they are advertised. Some call them the "A" mandrel.
Do a good turn daily!
Don
Do a good turn daily!
Don
ed4copies
Local Chapter Manager
It is actually NOT 7 mm.
One of the common misnomers is using the size of the hole we drill to identify everything that goes with it. When you are drilling a 7 mm hole (.2756") and inserting a "7 mm tube" (OD=.2655", ID=.2455" ish) and it goes on an "A" mandrel, which Don says is .24409 (sounds right to me!!).
The difference between the mandrel OD and the 7 mm hole is significant (11.5 percent)
Wow, I am slowing down---2 guys post while I typed!!!
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stonepecker
Member
so what is the difference between an "A" and a "B" mandrel?
The "B" mandrel is slightly larger. Here are the details from Arizona Silhouette's website.
"...95% of the pen kit manufacturers us an "A" or 7mm mandrel which is really 6.2mm in diameter. "B" mandrels are referred to as 8mm mandrels but are really 7.2mm in diameter. These are used for the larger pens such as the Cambridge, Churchill, El Grande and others. They use the "B" mandrel because it is more stable and will have a tendency not to flex as much as an "A" mandrel can."
Wade