2010 Shopsmith Mark V "Power Pro" Electronic Variable Speed Headstock

One of the most exciting things to be announced by Shopsmith since the Mark V was introduced in 1955 has got to be the development of the Power Pro headstock.  The Power Pro is a giant leap forward for Mark V, Mark I, Mark II, & Mark VII owners is many ways, but before we discuss them all
it might help to understand the original headstock, the image at right is from the original patent for the Mark V and shows the standard mechanical variable speed power train in the Mark V.  (Click the pic to Biggie Size)


Originally 3/4HP, the motor was upgraded to the current 1-1/8HP in the early 1960's.  Despite the increased HP all Mark V units are limited to a range of 700rpm to 5200rpm.  This was fine for the needs of the average DIY woodworker in the 1950's, but if you wanted to drill metal or to use large diameter Forstner bits, 700rpm's was just too fast.  On the other end of the speed range, Shapers run at 10,000rpm's.  The Mark V was promoted as having the ability to be a shaper, but at 5200 it's slow going. 


You'll notice in the drawing that there are two belts in the unit.  One V belt runs from a variable pitch pulley on the motor to a second variable pulley on the lower spindle. A second, smaller fixed-size pulley is also in the lower spindle, and this pulley drives a flat belt which drives a pulley on the top drive spindle.  This arrangement created a high speed lower spindle that turned 1.6 times for every turn of the upper spindle.  Why?  Because the folk who invented the original Mark V back in the 1950's knew that table saw blaces turn at roughly 3000rpm's, but a jointer's cutterhead turns closer to 5000rpms.  So, they made a high speed spindle that turned the jointer at it's proper speed while the saw blade ran at the same time at it's proper speed.  Smart.  In 1954 the flat belt was a toothed Gilmer belt.  This was replaced by a multi-grooved belt called a poly-V when the motor was upgraded to 1-1/8HP. 


Besides the limited speed range, one problem with the mechanical variable speed drive is that as the speed increases, torque decreases.  It’s actual possible to speed-up the table saw blade by slowing the speed down.  This little trick increases torque and prevents loss of power due to belt slippage.


So what’s different about the Power Pro?  Well, the lower drawing is my lame attempt at modifying the original drawing.  It shows a larger motor with a electronic control box mounted piggy-back style.  The V-belt has been replaced by a second, longer poly-v belt, and the entire variable pitch speed control has been removed. The motor is 1-3/4HP when powered by 100volts, but when powered by 220volts it’s a 2hp motor!  And because the speed is controlled electronically there is no loss of torque at high speed!  And speaking of speed, how does 250-10,000rpm grab ya?    Oh yeah!  That means you’ll be able to turn large platters and drill metal with ease.  And at the top end 10,000rpm’s is exactly what we need for shaping. 

The illustration has two black areas that need explaining.  The large black box is, well, a large black box.  This is the brains of the electronic variable speed unit.  Yes, there's a new touch pad on the front of the unit, but the real brains are found here.  The other black area is a steel spacer that separate the two high speed bearings on the idler shaft.


Another interesting ability of the Power Pro is the ability to run in reverse.  What good is that?  Well, it means that you’ll be able to reverse your lathe while sanding, which helps to speed-up the sanding/finishing process and creates smoother finishes.  But the real advantage of the reverse drive will be seen by the Mark VII owners who install a new Power Pro headstock on their Mark VII frame.  If you don’t know, the Mark VII not only lifts onto the drill press position, but it flips and lifts in the opposite direction, which puts the headstock under the table; Shaper style!   


So, how do I get one of these bad boys?  From what I hear Shopsmith is looking onto at least four options:

  1. You could buy a new headstock that replaces your current headstock.
  2. You could buy a newly rebuilt headstock that replaces your current headstock, perhaps with a core exchange.
  3. You could ship your headstock to the factory in Dayton, Ohio and have them upgrade it.
  4. You could buy a kit that allows you to retrofit your current headstock.  This may be a bit more complex than it first appears, because almost all the bearings in the headstock must be replaced with higher duty bearings.  This is because of the higher speeds, which the older style bearings were never designed to endure. 
The issue of "new bearings" on point three above is no small detail.  If you have a single bearing quill, you'll need to update to a double-bearing quill.  That's a simple upgrade and if you do any faceplate turning or drilling the improvement will be startling. 

The lower shaft is called the Idler Shaft, and it has always been a water pump bearing assembly.  Yes, this is exactly what it sounds like.  I wrote a post about this neat little bearing assembly some time back where I listed all the places where it's found on Shopsmith tools.  There are two problems with this assembly: 1.) It was never designed to handle the new 16,000rpm's of the Idler Shaft on the Power Pro.  2.) As far as the manufacturer of this assembly is concerned, Shopsmith doesn't use enough of these as it is, and if they switch to something different for the Mark V there's just not enough usage at Shopsmith to be interesting.  So.... the brilliant minds at Shopsmith have developed a new replacement bearing assembly that they've been using on production Mark V's for some months now with great success.  This new idler shaft will be required for any Power Pro headstock upgrades. 

UPDATE June 6, 2010
Shopsmith has introduced the new replacement Idler Shaft that I mentioned above as the replacement for the standard Mark V Idler Shaft.  (New Idler Shaft Service Bulletin


Update June 23, 2010

Your wait is over!  Well, at least your wait to see the Power Pro Headstock for your Shopsmith Mark V. Learn more about it over at Shopsmith's site: http://www.shopsmith.com/shopsmithpowerpro/diy_upgrade.htm
Here's a short video that shows the upgrade process.
Watch the video below to learn about the four ways you can upgrade your Mark V, Mark VII or Mark II to the new Power Pro Headstock, then visit this site to learn more: http://www.shopsmith.com/shopsmithpowerpro/ways_to_upgrade.htm
Updated June 24th, 2010:
Shopsmith announced that they are offering four optional ways for you to upgrade your MARK V Headstock to the new Shopsmith PowerPro.
One awesome part of this announcement is that no matter which Upgrade method you select, all parts that are included or replaced will be covered by a 5-year PowerPro Motor Warranty and a 2-Year Warranty on all Electronic Components, Belts and Bearings!
Let’s look at the options.
Owners selecting this Upgrade option will receive a brand-new MARK V Headstock, complete with the new PowerPro Motor, all electronic circuitry, Digital Control Panel, Two-Bearing Quill, Quill Feed Mechanism, Drive Sleeve Assembly, Pulleys, Poly-V Belts, Cord and Headstock Wedge Locks.
To install you just slide your current MARK V Headstock off the Way Tubes and slide the new Headstock on in its place, keeping your "old" Headstock as a "spare". 
This option is part # 556176 New PowerPro Headstock and is priced at $1899.
This option is essentially the same as Option #1 above...except that you will return your Old Headstock to Shopsmith for a refund.  Owners selecting this Upgrade option will receive a brand-new MARK V Headstock, as described above.  However, under this option, you will simply ship your old Headstock back to Shopsmith for a $200 Cash Refund.
556176 New PowerPro Headstock and is priced at $1899 - $200 rebate: Final price $1699.
Owners selecting the Refurbished Upgrade option will receive a fully refurbished (GRAY) MARK V Headstock, complete with the new PowerPro Motor, all electronic circuitry and Digital Control Panel. It will also include a two-Bearing Quill and Upper Drive Sleeve with new bearings; new Poly-V Belts and a new Power Cord.  The Headstock Wedge Locks, Quill Feed Mechanism and Headstock Casting will be evaluated and reconditioned, as necessary. 
Once you’ve switched to the Refurbished Headstock, simply use the packaging it arrived in to ship your "old" one (including Motor, Quill, etc.) to Shopsmith to receive your $200 Cash Refund.
556189 Refurbished PowerPro Headstock..... $1729.  The final value after $200 Cash Refund is $1529.
If you select this option, you will ship your current MARK V Headstock to the factory for upgrading. Shopsmith will install the new PowerPro Motor, all electronic circuitry and Digital Control Panel.  ALL remaining internal parts will be evaluated by Shopsmith’s Factory Trained Service Technicians and replaced as needed to upgrade your Headstock to today's high PowerPro standards.  Shopsmith will then ship your Upgraded  PowerPro Headstock back to you.
556178 Your Headstock, Reconditioned and Upgraded to  PowerPro  Status.....$1529
Owners selecting the Do-It-Yourself  Upgrade option will receive a new PowerPro Motor, all electronic circuitry, Digital Control Panel, new Two-Bearing Quill, new Upper Drive Sleeve Assembly, new Poly-V Belts and new Cord… all for self-installation in your current MARK V Headstock.  In addition, you will receive a printed Upgrade Manual, an Upgrade DVD and all necessary drilling templates, drill guide and bit for precise machining of the mounting holes for the new components.  It is estimated that the Upgrade process should require approximately four hours to complete.   If you currently have newer Belts, Upper Drive Sleeve or a Two-Bearing Quill… in order to protect your Upgrade Warranty, you are required to replace them during the Upgrade process and keep your current parts as "spares".  Replacing all of these internal parts assures that all components of your upgraded Headstock are up to today's high PowerPro standards.
556177 Do-It-Yourself PowerPro Upgrade Kit.... $1429