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Mandrel Question
Posted: Wed Jun 11, 2014 9:12 pm
by delong94
I bought a used Mark V back in February and some new single mandrels for pen/pencil turning came with it. They are from the old Shopsmith stores (Woodworking Unlimited) and the serial number listed on the package is 555695. Does anyone know what do I need in order use them on my SS? Can I mount it using the chuck and use the live center with it? I enclosed a pic I took from my webcam. Thanks.
Posted: Thu Jun 12, 2014 12:06 am
by Mike907
Yes, you can mount that mandrel in the drill chuck, unless the other end looks like
this one, then it would mount directly to the Shopsmith. The live tailstock center fits into the dimple in the end of the mandrel.
Mike
Mandrel
Posted: Thu Jun 12, 2014 12:11 pm
by delong94
Mike907 wrote:Yes, you can mount that mandrel in the drill chuck, unless the other end looks like
this one, then it would mount directly to the Shopsmith. The live tailstock center fits into the dimple in the end of the mandrel.
Mike
Thanks. It doesn't have the endpiece like that. I'll have to use the chuck and live center. I was looking at the one you listed. I may get that one later on. I appreciate it. Now I'm wondering what drill bit size to use to make blanks!
Posted: Thu Jun 12, 2014 12:22 pm
by Mike907
The drill bit size will depend on which pen kit you have. 7mm is common, but there are many more sizes of
pen kits.
Mike
Posted: Thu Jun 12, 2014 1:41 pm
by terrydowning
As Mike stated, it all depends on the size of the tube. Bushings are then used to make up the difference between the mandrel and Inside diameter of the tube.
Posted: Thu Jun 12, 2014 5:24 pm
by anmius
I personally cannot support the concept of using the drill chuck to hold a pen mandrel or for any other lathe/turning use. It is not designed to take the lateral stresses that turning will put on it. You would be better off using the router chuck attachment to hold the mandrel (514632 or 514631--$18.98). Or you could purchase the dedicated Shopsmith compatible mandrel from someone like Penn State Industries ($17.95). In either case, it isn't a very large investment to do it correctly.
Posted: Thu Jun 12, 2014 7:15 pm
by delong94
Thanks. I have a 1/4 inch router attachment and will try that.
Posted: Mon Jun 16, 2014 5:39 am
by skou
anmius wrote:I personally cannot support the concept of using the drill chuck to hold a pen mandrel or for any other lathe/turning use. It is not designed to take the lateral stresses that turning will put on it. You would be better off using the router chuck attachment to hold the mandrel (514632 or 514631--$18.98). Or you could purchase the dedicated Shopsmith compatible mandrel from someone like Penn State Industries ($17.95). In either case, it isn't a very large investment to do it correctly.
Animus, we will disagree.
We're turning a pen blank here, not a bowl.
I've used a drill chuck to do some mill work, (on aluminum no less) and it worked just fine. (But, I'm using a real {read that Cast Iron} Shopsmith, not one of the newer aluminum-based ones.) Milling involves holding a tool in some kind of holder, and working sideways(or lateral stress) on a work piece. Much more side loads than turning would involve, especially, a pen blank. And, we're working between centers, not like doing a bowl, hanging out in the open.
Besides, you are working off of a 1/32nd inch wall thickness (if not less) brass tube, that holds the pen blank. I'm pretty sure my cast iron 10 series lathe will not have any issues. You guys running Mark X stuff may have issues, though.
steve
Posted: Mon Jun 16, 2014 4:28 pm
by anmius
skou wrote:Animus, we will disagree.
We're turning a pen blank here, not a bowl.
I've used a drill chuck to do some mill work, (on aluminum no less) and it worked just fine. (But, I'm using a real {read that Cast Iron} Shopsmith, not one of the newer aluminum-based ones.) Milling involves holding a tool in some kind of holder, and working sideways(or lateral stress) on a work piece. Much more side loads than turning would involve, especially, a pen blank. And, we're working between centers, not like doing a bowl, hanging out in the open.
Besides, you are working off of a 1/32nd inch wall thickness (if not less) brass tube, that holds the pen blank. I'm pretty sure my cast iron 10 series lathe will not have any issues. You guys running Mark X stuff may have issues, though.
steve
I'm glad you have had good success using the drill chuck for a purpose for which it was not designed. I still maintain that the drill chuck was not designed for lateral forces like turning, milling, routing, shaping. That is precisely why Shopsmith offers a special device to hold router bits and shaping bits.
Posted: Mon Jun 16, 2014 6:09 pm
by JPG
So has anyone determined WHY the drill chuck is unsuitable for operations involving 'side thrust', or are we citing a mantra with no forethought.
My own 'opinion' is that the drill chuck only supports the shank at three locations around the shank. This allows side thrust to potentially move the shank outward at the three locations opposite the chuck 'fingers'.
This only becomes relevant if the side thrust is sufficient to actually move the shank.
I doubt pen turning will create sufficient side thrust.
One thing to consider though is at small shank diameters, the fingers are more fully extended and thus have less support from the chuck body.
However the router arbors do provide 360 degree support and would be the preferred choice. Why push fate?;)