Thread: Dictionary of terms

Okay then,
I will start it off here, and if this is usable, then move it to a permanent post.
These are machine arbors, commonly refered to as Morse Tapers, (MT)also known as a machine taper.

Shown above are two of the three most common sized most of you will encounter, a number 2MT on the left, and a number 3 MT on the right.
Not shown is a number 1.
Machine tapers run from #1 to #7, the larger the number, the bigger the arbor/taper.
There is a #0, but unless you are a jewler, you will never see one of those.

Note that the small end of these two are different.
The left, #2MT, has a flat end, which has a 1/4" x18 threaded hole bored into it.
This hole facilitates a draw bolt, used to hold the taper/arbor in a spinning head stock drive shaft.
The #3 on the right has a tang end, this end is most commonly found in arbors used in drill presses and milling machines, the tang locks into a slot in the drive shaft.
Both sizes come both ways, so check that the one you purchase are flat bottomed, the tang can cause problems with most lathes, although it is needed in drill presses.

Shown above are some of the most common uses for MT arbors, all 3 of these are #2MT, the most common size you will encounter.
Shown are a collet chuck, a keyed Jacobs or drill press chuck, and a key less Jacobs chuck.
Jacobs chuck has become the defacto common name for these style chucks, although Jacobs is also a trade name of a manufactuer ofthese chucks, the keyless chuck shown is made by Jacobs.
The two Morse tappers you will encounter most often in pen turning are the #1MT and #2MT.
The #1 was the standard in home shop lathes for a long time, but has been replaced by the #2MT over the last decade, most of the Mini and Midi and full sized lathes you will use have both the head stock drive shaft and the tail stock feed shaft using the #2MT without a tang.
The most common use for a MT arbor is your pen mandrel and what are know as "centers", both the drive center in the head stock and the center in the tail stock.
Centers will be covered later, I am sure, but there are two basic types, the spur drive center, used to apply the driving force to the stock you are turning, and the tail center, used to apply pressure to the stock against the drive center and provide a pivot point for the work/ stock to spin on.
Two most common tail stock centers are a dead center, which is a solid piece most often used in metal work, and live center, which has bearings and spins freely while applying pressure to the work piece.
If you are unsure of which MT your lathe uses, the number will be listed in the owners manual in the specification section, but again, for almost all new wood lathes, Jet, Delta, VicMark, Rikon, Powermatic, Oneway and such, is is a safe bet it is a #2MT in both the head stock and tail stock.
Most home shop drill presses will use a #2MT arbor with a tang.
http://en.wikipedia.org/wiki/Machine_taper
This link covers most machine tapers, and the history on Stephen Morse who invented this method on attaching tools to lathes and drill presses.

Thata a great start Ed. Sorry about the delay in replying; I have not been in range of my computer for a couple of days. I think photos with a description is the best way of presenting the items.

In terms of preparation of a dictionary, I need some advice from one of the moderators as to how it can be placed in the tutorial section. As it needs some order in putting it together, I am happy for anyone interested to email me their contributions and I will put them in alphabetic order into a single document that can then be posted on the forum. Obviously a few drafts on the thread first would not go astray so that we can get input from others.

I am happy for any thoughts.

Greg

To continue with centers...
Centers are used to both drive the work piece from the headstock side, and to support the work piece and provide driving pressure from the tail stock crank.
Centers are either a drive center, or a dead center.
Most drive centers are variants of the spur drive, and tailstock centers, also know as dead centers, fit into two categories, live centers, (with a bearing that allows it to spin) and dead or solid centers, just as the name implies, it does not spin.

Shown here are 7 of the most common centers, all are MT2 taper except the far left one, which is a center drive insert, designed to be used in conjunction with the jaws of a 4 jaw chuck, this allow the turner to switch from turning flat work to spindle work without having to remove the chuck..
From the left, a drive center insert, shown below so you can see the part that is grasped by a set of chuck jaws, which drive the center instead of a MT2 taper.

second from the left is a spur drive center, most midi and mini lathes come with this one as standard, it is a general purpose center.
3rd from left is toothed drive center, with a spring loaded center point, this is designed to allow releasing drive tension with the tail stock crank, and removing the turning with the lathe still in operation, inserting a stock work piece with a pre-drilled center pilot on the spring loaded point, then tightening the tailstock back up allows production turning on a fast pace.
4th is a replacement spur drive center, along the lines of the standard one that comes with lathes, but the spur is thinner in diameter than standard, this allows for it to fit into recesses if needed..
5th is larger version spur drive, you would use this to turn heavier and longer, more bulky stock.
Both 4 and 5 have replacable center points, held in place by a set, or grub screw, you can see the screw in the photo.
6 and 7 are both live centers, they fit the tailstock and provide support to the end of the work piece, for pen turners they also provide the pressure to seat the mandrel taper in the headstock and drive the mandrel. the 6th one comes stock with most mini and midi lathes, the 7th is a 60 degree cone nose live center replacement, both of these have bearings in them that allow the cone part to spin freely, greatly reducing noise and wear on the mandrel.

Next to last photo is a dead center, it is a solid piece of high strength steel it is also a standard item that comes with a lot of mini or midi lathes,it fits in the tailstock and is used most often for metal turning, but as it is a #2MT, it will fit in the head stock and can be used in conjunction with a live cone center in the tailstock and allow you can drive a pen blank as shown.

Several member have made up special bushings to accomidate this practice, there is a tutiorial and a few threads that cover this.

Above is a standard #2MT mandrel, which for most pen turners replaces the drive center, the dead or tail stock center fits up against the right end and provides pressure against the the #2MT to drive the mandrel, hence most pen turners will use a live cone center in the tailstock, as the bearing reduces friction, extendes the life of the mandrel and is much more quite, plus it needs no lubrication as a solid or dead center would.