**Please EMAIL us if you wish to order a custom size**   We cut down a 5/8 or 3/4"mandrel (EXM625 or EXM750) from our inventory.  Please allow an extra week for us to ship so that we can cut the mandrel down for you.  Please Note:  the knurling will be partially or completely cut off and can not be added back on.

Diameter options for the EXM Series Mandrels are:   .590" to .620" -OR-   .710 to .745" and can be Straight Shank or Morse Taper shank.  

**  Please note the size desired in the comment box at checkout once we have enabled this item for your order.    

Be sure to check your taper size on your lathe before purchasing if you are ordering a MT shank mandrel.  #1 Morse taper is ≈.475" at the large diameter side of the taper.  #2 Morse Taper is ≈.700" at the large diameter side of the taper.  Tapers are NOT interchangable without adapter sockets.  We have seen many of the import lathes with incorrect taper specifications in the manual (ie Manual says #1 MT, but the machine actually has a #2MT) - so be sure to check before you order.

Using a tail stock while turning is required unless you fabricate a "draw bar" to hold the mandrel in the head stock through the spindle.  Using "all-thread" through the spindle, with a washer, and a nut on the back side is a common practice.  Be sure to cut the "all-thread" to the shortest possible length to avoid injury.

The call portion of the mandrel is ≈2.6" long.

The EXM Series Mandrels are made from 4140 Steel, and uses the more robust NPT expansion plug design for added durability.  Please note the knurling will be cut down slightly to achieve the smaller diameter.  This will mostly negate any additional grip created by the knurling.  The threads in the back of the taper for the draw bar is 3/8" - 16tpi.

Please note, this is a cut down version of the .625" or .750" Expanding mandrel.  The knurling (checkering type pattern on the mandrel) will be partially cut off to bring the OD down to your desired size, but is partially visible.  Operationally the mandrel is no different and should not require any additional force to lock the part on the mandrel.

Expanding mandrels have a limited range of expansion before damage to the mandrel can occur.  Typically your bore should not be larger than .010" over the size of the mandrel.  Though the mandrels will expand beyond that point (some more than others depending on model and diameter), alignment will suffer if the bore is any larger than mandrel and at a certain point the mandrel will be damaged and could become unusable if the bore is oversized by too much.  If you have issues with a mandrel holding a blank, the first thing you need to do is inspect your bore.  Measure each end with, at the least, a dial or digital caliper (something that reads in thousandths of an inch) to identify the actual size and if there is any taper.  Any more than .010" oversize and you will need to look into your drilling equipment and address the issues there, or look into drilling undersize and using a chucking reamer to bring the hole up to size.

Expanding Mandrels with #2 MT have a 3/8" - 16 threaded end for a draw bar to hold the mandrel in place for turning without the tail stock.

A draw bar is basically a rod that holds the mandrel in the taper.  The easiest method to make a draw bar is get some "all-thread" the size of the threaded hole in the back of the mandrel, a couple washers and two matching nuts.  Insert the mandrel in the head stock, then slide the all thread through the back of the head stock and thread into the mandrel.  put on the washers and nuts, then mark the rod.  Remove the rod, and cut at your mark.  Reinstall the threaded rod from the back, and tighten the first nut, and then use the second nut as a "jam nut" - locking the other nut in place.  Do not use these mandrels without a tail stock unless you have installed a draw bar or the mandrel can fly out causing injury and or damage to your equipment.

Drilling the .618" bore is challenging without the use of a boring bar on a metal lathe or utilizing a specialty chucking reamer (if one can even find one).  If you need acrylic or Acetal (Delrin) blanks bored for .618-.619" guts, we can do that for you (see Services on the main site).

This is the recommended mandrel for a beginner and for those goose call kegs using sub-5/8" goose call guts, like the SR2,3,4,& 11.

Replacment expansion plugs are readily available at any hardware store (they are 1/4" NPT Socket head pipe plugs for the .625" mandrel and 3/8"NPT for the .750" mandrel) as well as under the mandrel parts category here.

If your desired size can not be accomodated in an EXM series mandrel, contact us about a custom cut EA series.  The EA series can be made from any diameter between .425" and .875".