The Spank-O-Matic can strike extremely hard. At the system’s maximum air pressure of 150 PSI, over 250 pounds of force shoot the paddle forward in a smooth burst of power. The SOM XP model doubles the mechanical components and provides additional acceleration and power. With its twin cylinders, the SOM II XP delivers over 500 pounds of striking power at 150 PSI.  The current SOM models have a traverse angle under power of 112 degrees, thanks to geometry improvements is 2012 and 2015.

For more about the striking power of the SOM II, check the (this content isn’t on the new site yet) for a heads-up comparison against the Robospanker. Prior to either geometry change, the SOM II was proven to hit more than 2.5 times harder than this longstanding spanking machine set to its highest power… the SOM is now signficantly more powerful.


Operation of the SOM II itself is very quiet. Both the compressor and strikes will be significantly louder than the machine. Compressors vary widely, and of course only make noise when running. The Senco compressor I recommend is extremely quiet in operation. In general, if you’re OK with the sound of a hard paddle smack on an ass you’ll be OK with the total noise picture of a running SOM II.

In the manual mode, there is no minimum… the machine will happily wait for a button press for minutes or even hours. The minimum striking pace in the automatic modes is 4 per minute, or 15 seconds between strikes. In either case, the system enforces a minimum 1/2 second paddle recovery time. Add this the the time to make an actual stroke and the top speed is about 90 strokes per minute.

The SOM is a great addition to any spanking party, and really draws a crowd! It’s also quite simple to move around, because it breaks down into a very compact bundle. The machine itself, when fully disassembled, takes up about half of the box in which it ships… 36x12x12″. What I’ve found convenient is to bundle the parts in a blanket (to prevent them dinging each other) and sticking the result in a hardsided golf bag carrier. This inexpensive plastic case is perfect, and leaves plenty of space to carry your other tools as well. A small compressor like the Senco completes the travel setup.

The Spank-O-Matic has some serious advantages over the Robospanker. Check out the Video Comparison section (coming to new site soon) and you’ll note that the system is smartly designed to be easy to adjust in every way. The SOM II is vastly more adjustable… infinite height and angle.  Is your target ass exactly 10″ off the floor? Mine neither!

You’re not limited to three levels of spanking power, but an infinite adjustment… and you can change power instantly and at any time from the hand control instead of stopping to fiddle around in the guts of the machine.

The SOM II can spank faster and slower, harder and softer. The SOM II hand control includes a computer that can take control of your spanking with eight automatic modes, or you can manually operate the machine as a push-to-spank system. In contrast, with the Robospanker, you push a button and it starts to spank every so often. Period.

Every SOM II system locks down as a rigid system, ready to spank with fully efficiency, while the Robospanker teeters about on it’s single wobbly extending leg (note: Robospanker has quietly added a small screw that limits this teetering, but it remains inferior to the rigid SOM stands).

Finally, the accessories available for the Spank-O-Matic kick butt: the Automater to move the strike spot during your session, a highly functional bench, and a wide range of end effectors. I used to offer my effectors for the Robospanker, but discovered that they were all too heavy for their rubberband to power effectively.

There is no area in which the Robospanker is a better spanker. Not one.

The standard SOM Head, with a single pneumatic cylinder, is the best choice for most people.  At 150 PSI, the cylinder accelerates the effector with 250 pounds of force.  The SOM head will achieve a higher terminal velocity with lighter weight effectors than the SOM XP Head.

The SOM XP Head uses twin cylinders and valves to accelerate the arm with 500 pounds of force at 150 PSI.  It uses twice as much compressed air as the SOM head.  With light weight effectors, the SOM XP head will have a slightly slower terminal velocity than the SOM head.  With heavier effectors, the SOM XP head can strike much harder than the SOM head.

The crossover point, where the two heads deliver similar performance, is roughly 1.5 times the mass of the Broad Lexan Paddle.

There are two differences between these two complete machines:

1 – The Stand.  The Spank-O-Matic features a welded steel stand that assembles without tools and is the heavier — and thus more stable — stand.  The Spank-O-Matic LT features a stand of aluminum extrusion and specialized fittings.  This stand, while very rigid, is substantially lighter and does require a 13mm wrench or socket to assemble.  Both stands can be put up or taken down in a couple of minutes, and they have quite similar dimensions.

2 – The base configuration of the SOM LT includes a special limited -function hand control to keep the cost low.  This may be upgraded to either full control system at time of purchase.  The LT hand control offers only “periodic” as an automatic mode of operation… a stoke every set amount of time.

Both machines offer either the SOM or SOM XP head.  There is no difference in striking force between the two.

How something feels is obviously subjective, but I can provide some description that may be helpful.

When dealing with generally rigid effectors such as those suited to use with the Spank-O-Matic system, the most important description is the toy’s location on a spectrum from stingy to thuddy.  Sting is shallow, sharp impact.  Thud is deep and broad.  Sting stays close to the surface and any bruising will be superficial, while thud bruising can go quite deep beneath the skin.  Snapping a rubberband against one’s skin is near the peak of sting.  A full on stroke with a wet bath towel is extreme thud.

Some rules of thumb:

Lighter implements tend to be stingy.  Heavier implements thud more.  It is, however, not so simple as effector weight, but more like weight contact area.

Implements with a high surface hardness tend to sting.  Softer ones thud.  This difference can even be felt between oak wood and Lexan (polycarbonate plastic), as the latter is noticeably harder.

Although unrelated to effectors, it’s also worth noting that the target’s muscle and skin tension changes the impact.  Tense muscles and/or skin  keeps any given contact closer to the surface, and thus stingier, than relaxed.


Canes are very stingy.  In large diameters (over about 1/2″) they _also_ thud.

Wide paddles tend towards sting.  Broad Lexan, Fraternity.

Lexan paddles tend towards sting.  Broad Lexan, Staged, Whack.

Thin paddles tend towards sting.  Staged.

Thick paddles tend towards thud.  Whack, Fraternity, Ruler.


The Cane Holder, included with the Cane Set, can mount anything with a roughly round handle between about 3/16″ and 3/4″ in diameter.  Smaller diameter handles can be held by thickening them with tape.  Larger handles might be help with longer bolts.

Using natural canes such as rattan should be done with caution.  The SOM system accelerates very abruptly, and natural materials will split or break under the strain at some point.  If you choose to use natural canes, examine them frequently.

Other paddles may be mountable.  Paddles mount to the SOM head’s swinging arm with two 1/4″ bolts, through holes spaced exactly 2″ apart.  If you’re able to drill these two holes into the handle of your paddle, you can mount it.  Same caveat applies to paddle materials… they’ll be subject to extreme stress.

The effectors I offer are all between 30 and 34 inches in length.  I consider this an excellent balance between convenience (length to store and ship, and the space required for the swing arc), but there isn’t a hard and fast rule.  Shorter effectors that are light weight will have a lower tip velocity, and will require a higher power/PSI to deliver a similar strike.  Short heavy effectors can be quite effective.  Longer effectors of light weight can have an elevated tip velocity and striking force.  Long, heavy effectors are not likely to be effective.

The SOM head connects to a 12 VDC power source to operate the entire system.  The Control System takes power from the head.

Each complete system comes with a 12 VDC power supply which can be operated from grid power anywhere in the world.  This power supply arrives with a detachable wall cord for a US 2-prong outlet.

It is possibly to power the SOM system from another 12 VDC source, such as a car’s cigarette lighter.

Note that in any case, you also need a source for compressed air.

The SOM II is extremely adjustable, and built to work in any orientation or position. The head unit and attached paddle adjust from floor level up to about 36″ high. The head swivels to point the paddle in any direction, including swinging upward from a low position (think ball-busting). The head unit attaches and adjusts on its mount with a structural pipe fitting, using an included 3/16″ hex key (note that prior to July 2012, units shipped with a 1/4″ hex key and single set screw pipe fittings).

The SOM II stand assembles and adjusts with industrial channel and matching channel nuts, secured with easy-to-use hand knobs. The LT stand and bench both use aluminum extrusion and specialized t-bolts, which require a customer-provided wrench to use. Both designs create very firm and strong settings that are infinitely variable. The legs of both stands adjust independently and can be offset by any amount to clear obstacles or allow the unit to pull closely up to furniture.


The gross power control is incoming air pressure. The system components are rated to 150 PSI, and will likely put up with higher pressures… exceeding component limits will not cause damage, but at some point the valve will not close. Should this occur, reducing pressure will return the system to normal operation with no lasting consequences. Note that the remaining changes each represent a _slight_ increase from stock form… most of your gain will be from maximizing the air pressure.

Your SOM head has a strong external spring to assist with paddle return. Stretching it during the stroke requires about 5 pounds of force per inch, or 15 pounds total… and this directly reduces the spanking force. At 100 PSI, cylinder thrust of 176 pounds is reduced to 161 pounds. This spring is sized to return the Fraternity Paddle (heavy oak paddle) when used vertically. If you are using a light effector like a cane and/or using you machine with the paddle swinging more horizontally, you can probably remove this spring under those conditions, thus increasing spanking force. If your paddle will not return, re-attach the spring.

Adjusting your target such that the contact point is near the end of the paddle will result in greater impact.  Because the effector pivots from a fixed point, points farther out on the paddle are moving faster.  Also, make sure your effector is landing flush… that is, contacting the target on the flat.

A very slight increase in power can be had by swinging downward, even by a small amount.  Likewise, using a narrower paddle will minimize air resistance.

Finally, if you have a smaller compressor it is probably equipped with a very restrictive regulator… that is, the regulated air must pass through a very small aperture in the regulator. Swapping out for a larger regulator allows much faster delivery of pressurized air and improved performance. Selecting a larger compressor also addresses this issue.

No, this is a myth created by Robospanker. The Senco manual and those of other air compressors will indicate that you should not breathe the air stream, a warning typically accompanied by a picture of a hose running to a person’s mouth. This warning relates to using the compressor as your source of air, such as filling a scuba tank. Such manuals also indicate that using the air compressor to spray hazardous materials like paint must be done in a well-ventilated area. Using the SOM system does not involve spraying hazardous materials, and claiming this is more general than indicated in the manual is underhanded.

An air compressor takes in room air, compresses it mechanically into the tank, and releases that exact same air at a higher pressure through the SOM II’s exhaust vent. This process does not mysteriously poison either the air that goes through the compressor or the room air more generally. Robospanker’s claims are simply untrue.


If you use it too frequently and too hard, you will definitely suffer persistent bruising with risk of leatherbutt 😉

Some are, some aren’t. The Senco PC1010, which I use myself, is very quiet at 67 dB, and is quite inexpensive as well. Up the scale a bit, the California Air Tools line of compressors are rated at a mere 60 dB. DeWalt makes several nice models in the 70-75 dB range, also quite quiet. Of course, all of the models make noise only when running, which is a minority of the time with a conservative tool like the SOM being used. For reference, 60 dB is about as loud as a quiet conversation from 10 feet away. The 67 dB of the Senco is half the noise of an average vacuum cleaner from 10 feet away. Every 3 decibels doubles the output power (measured by equipment) and every 10 decibels doubles the perceived volume (how loud it seems to a person).

There are three relevant criteria by which you can measure a compressor for this purpose: maximum pressure, noise in operation, and air delivery capability. Let’s examine each in turn.

Maximum pressure is stated in PSI, or pounds per square inch. This measures “how compressed” the air is, and the force with which is comes out of the compressor. The SOM system is at its maximum power with incoming air pressure of 150 PSI. Pressures above this may result in unusual operation of the valve (mostly, it might be held open by the high pressure). The majority of consumer air compressors have a maximum pressure of 120-125 PSI, including the Senco PC1010. As a user of such a compressor, I can assure you this is sufficient for a very powerful whack. However, you can get about 20% more force if you find a compressor that can deliver at least 150 PSI.

How loud is the compressor, or how quiet do you need it to be? The Senco PC1010 is rated at 67 dB, about as loud as an average conversation. For reference, 70 dB is like an average business office and 80 dB is a hair dryer. The decibel scale is logarithmic… a small increase in the number means a more significant increase in the noise it represents. As a general rule, if a compressor is not marketed by its manufacturer as producing XXX decibels, then you can assume it to be pretty loud. Quieter compressors will include a decibel rating in the specifications, and unless you need extreme quiet you’ll be happy at 70 dB and under.

The air delivery capability is easy to measure, but it can be difficult to assess your needs. Air output is measured in CFM (cubit feet per minute) at a given pressure… usually 40 PSI and 90 PSI, and we’ll focus on the 90 PSI air delivery. The Senco PC1010 delivers 0.6 CFM at 90 PSI. This unit will not keep up with the SOM using the hardest strokes at the fastest rates… that requires more air flow than the PC1010 can maintain. The unit can keep up with the hardest strokes at about one every 3-4 seconds, forever. Likewise, it can deliver a series of very fast hard strokes.. but then needs to rebuild pressure. A unit rated approximately 1 CFM should full power the SOM (hardest strokes at fastest pace). Note that at any setting, the SOM XP head unit requires twice as much air as the standard SOM.



Certainly! My personal criteria include minimizing the noise produced. If you don’t care — maybe you can put the compressor in the garage and run an air line inside — then it’s very easy to select a compressor. If you also want a quiet unit, check out the following (and there are doubtless others):

Update:  There is a surprising new entrant in this space that has basically overridden the suggestions below, and that’s Husky by the Home Depot.  They’ve introduced a line of three quiet compressors that and definitely the best value going.  The smallest is 1/2 HP, 1 gallon, 60 decibels, and very similar to the Senco… but offers 135 PSI instead of 120 PSI.  The double hot dog is only slightly more expensive but a lot more capable at 1.3 HP, 4.5 gallon, 65 decibels and 175 PSI!  The largest is a 20 gallon upright roll-around with 1.5 HP 73 decibels and 165 PSI.  These are great spanking choices.

Senco makes several units, but only the PC1010 is marketed as “ultra-quiet”
The Rolair JC10 is a larger unit, reasonably priced, and at 60 dB extremely quiet
California Air Tools (formerly GMC Syclone) makes a line of compressors, all of which are very quiet
Porter-Cable’s C1010 is quiet at 71 dB, delivers a bit more air than the Senco, and has a 135 PSI max pressure
DeWalt’s D55140-R appears to be identical the PC1010, and may be available at a bit lower cost, especially refurbished
Ingersoll Rand P1IU-A9 is one I include for its quality reputation; reviewed as quiet by owners but not marketed with a number, very large and heavy but goes to 135 PSI.



The spring is a compromise, as return force directly takes away from striking force. When you have a setup in which the effector you’re using will not return, you can add more return force by adding rubber bands in parallel with the spring, between the same two posts. That can be several individual short bands or one long one wrapped several times, or whatever combination you can develop.

The alternative is to seek a stronger spring, but switching springs on the forward washer is (for me at least) some work. The device requires an extension spring with loop ends, effective length 9-12″… that means it must be slightly tensioned at 9″. The standard spring is 8.5″ length, 4.6 pound static load and 3 pound rate. That means it takes 4.6# to start stretching it and 3 pounds additional to stretch each inch. You can probably fit a spring up to 1-1/8″ diameter, although the standard spring is 1/2″ OD.