Augmented Reality is Already Here and Has Been for a Long Time

After finishing up my exams, I managed to get my 1970 Volkswagen Beetle out for a number of drives with the family while enjoying what’s left of summer.  I really like driving my Beetle.  It is a true analog experience.  vwbugThe cable throttle is linear and responds to my inputs as I would expect.  The clutch is also moved by cable and gives excellent feedback as to when it is about to engage.   The lack of electric power steering (or any power steering for that matter) gives good feedback to the road conditions.  The brake pedal requires a high amount of force, but braking is linear in response.

Lately there has been much talk of augmented and virtual reality regarding how it is going to change the way we live.  But I have some news for you: it is already here and it is frequently used in our cars.  For example,  since 2012 the Volkswagen GTI utilizes something called the Soundaktor (no – I’m not making that up! –!).  The Soundaktor produces artificial engine noises to ‘enhance’ the driving experience.  Volkswagen isn’t only company using electronics to create artificial sound; numerous other car manufactures use the car’s entertainment unit.

Nearly all new cars today (in North America) utilize throttle by wire: a sensor in the throttle pedal communicates with a computer which turns the throttle plate.  This allows manufactures to program how they want the accelerator to respond, and it’s the reason you’ll find some cars you drive are very sensitive on the throttle response and others more relaxed.   Electronic stability control is required by law ( since 2012.  In these systems microprocessors change the response of the throttle and braking system (or our human inputs) to try to maintain control of the vehicle if it senses wheel slippage or other out of control movements.  There are numerous other examples of computers used to alter or influence the actual response of a system – regardless of human input.

If your Soundaktor is always pumping in simulated sound into your car, how do you know what your car really should sound like?  What happens if you end up in a situation where the programmed routine isn’t sufficient for the situation you find yourself in?  This constant surge forward to digitize our analog world unfortunately warps our sense of who we are, what we are capable of, and warps the physical world that we live in.

Technology that augments reality and helps us do things better is not always a bad thing and allows us to do things we couldn’t do on our own; however operating in a true analog world is also a skill that is very important to develop, maintain, and is a fundamental part of who we are.  This is why it is so important for kids to have play time outside.

It’s why I have a manual lathe, manual mill, and 1940s shaper in the garage, and why I really like driving my Volkswagen Beetle.  I guess it is my play time outside.

The Amateur’s Lathe

LH Sparey’s Amateur’s Lathe is on my  ‘must read’ list for not only anyone interested in home shop machining, but also anyone interested or studying mechanical or manufacturing engineering.  I think that the book is so good that it should be a mandatory part of a first year engineering course.


Even though the publishing of this book is seriously showing its age (the drawings, typing and photographs could be updated in quality), the content is very very good.  Sparey approaches the information within the constraint of doing work on one piece of equipment: a small workshop lathe.  So many teach that the lathe is only for turning work, such as turning small shafts or bushings.

The reason I like the book so much is because it encourages you to think outside of the box.  It helps develop the skill of trying to complete a project using the tools at your disposal.  It teaches one of my favorite words: ingenuity.  “Ingenuity is the quality of being clever, original, and inventive, often in the process of applying ideas to solve problems or meet challenges. Ingenuity (Ingenium) is the root Latin word for engineering.”  Ingenuity is solving a problem within the constraints you are placed in.  And remember constraints produce good design.

Ingenuity is the skill we desperately need in engineering.  Engineers today are really good at math, but math is only one tool to solve a problem.  At some point we have to move from the theoretical to the practical.  I remember  one of my professors (a mathematician / engineer) jokingly told me that solving the problem is the important part – you can find any idiot to do the math.  He was joking, and wasn’t downplaying the importance of mathematics, but rather highlighting the importance of solving the problem.

So if you are a mechanical or manufacturing engineer – read the book to get an interesting insight to what a small bench lathe can really do – while actually learning how to use a lathe.  If you are someone working in your shop the book has excellent insight and information to get those machining projects done you think you don’t have enough tools to do.

It’s on Amazon here.  Don’t let the bad reviews fool you – you have to read the book and think not just look at the pictures.


Under the Dome

This is Manufacturing Matters – my weekly opinion on manufacturing topics.

The pollution problems facing countries like China are not getting the publicity in the main stream media they deserve.  Below is an excellent documentary detailing the problems from a first hand account.  The documentary is long – over 1 hour, but I highly recommend you view it – I consider it a must watch.  At the very least those involved in making company purchasing decisions for goods coming out of China should review their suppliers.


Every tool was used

I’ve been very busy lately outside of the shop on coursework so I haven’t had a lot of time in the shop this week.  I’ve managed to get some time in the shop making 4 more brackets for my friend’s Audi S4 antics:


The brackets are made out of 1018 cold rolled steel.  What I really liked about this project is everyone of my powered machine tools (bandsaw, shaper, lathe, mill, belt sander, bench grinder!) was used.  The method went something like this:

  • Cut to size on the bandsaw
  • Face and machine to thickness on the shaper
  • Square up on the mill
  • Drill the holes and start tapping on the mill (finish up by hand)
  • Cut the large radius in the lathe using a face plate setup (I used a hacksaw first to remove most of the material!)
  • Cut the outside profile on the bandsaw
  • Add the profile radii on the belt sander
  • And of course, sharpening all the tools on the bench grinder and / or belt sander

It was the first job I really put my newly acquired 7″ Ammco Shaper to work.


The shaper worked great, and it was really nice to just let the little machine work away while I was drilling on the mill.  Would I trade my mill for a shaper?  No, probably not, but the little shaper is a pretty useful tool.  It did a very good job on finishing the 1018, which can be really gummy at times with poor chip control.  I used a 1/4 HSS turning tool with a small stepper over for roughing and finishing.  Roughing used a depth of cut of about .020″, which I though was fairly respectable given the 1/3 hp motor powering the little shaper.  I’ll be posting some more details on the HSS tool geometry I used soon.

My Favorite Tool

This is the first post of Manufacturing Matters – my weekly opinion on manufacturing topics.

It’s a bit of a running joke in my mechanical family that you can fix anything with a hammer.  We laugh, but seriously, could you live without a good hammer?  A hammer is an indispensable tool – I use them every day at work and in the shop. In fact I use multiple hammers in a day.

Here is my favorite hammer that I use in the shop while machining:thebasher

Its a zinc cast hammer made by Forest City Castings in Canada.  I use this hammer pretty much exclusively while doing setups, and I love it.  It’s also the first hammer that I’ve ever used that has instructions on the handle.

All kidding aside, the reason I like this hammer so much is because it is made in Canada at a price that you can afford, and is a quality product.  Disclaimer: I have ‘off shore’ tools in my shop and I don’t want to come across as being a hypocrite.  The ‘off shore’ tools in my shop are there because I couldn’t find tools made here that were reasonably affordable (new) or in reasonable used condition (used).  I would have gladly paid more money for my mini mill if I could get a made in North America one.  The reality is if you want a mini mill you don’t have much choice.

Some people say we just can’t compete with countries like China.  Companies like Apple routinely tell us that they couldn’t function without countries like China (read we need shareholder value on the back of inexpensive labour and lax environmental laws).  I beg to differ because every time I’m setting up in my mill or shaper I’m using my affordable, Canadian made, zinc cast hammer – which is arguably a commodity product.  It is made by a great company that is helping its community by providing good, honest jobs.  I’m reminded that yes we can effectively manufacturing  things here, and yes we can compete with countries like China while treating the worker and environment  with the respect and dignity they deserve.

So this hammer is inspiration for me to try and make a difference in the manufacturing world I work and live in.  It reminds me everyday that a good product at a reasonable price is possible to be sustainably made right where I live.

If you want one of these hammers, (I think they make them in aluminum and zinc) send me an email and I’ll try to get you one as I don’t think you can purchase them online.



Bench Grinder Balancing with a Smart Phone

Disclaimer:  Bench Grinders are dangerous.  If you improperly mount the grinding wheels they will explode and hurt or kill you.  If you mount damaged wheels they will explode and hurt or kill you.  Find someone to help you or educate yourself thoroughly on appropriate safety before attempting any work on a bench grinder.  Attaching weights to the bench grinder to balance it is not a straightforward task.  The weights could fly off when the machine is running and cause serious injury.  Do so at your own risk!

There with that out of the way, I found another use for my smart phone in the shop: dynamically balancing my bench grinder.

Here is my bench grinder.  It is a 8″ Ryobi from Home Depot.  It spins at 3600 rpm which is a little fast for HSS tool bits but it works and has plenty of power for what I do.  Of course I removed the wheels it originally came with and purchased 2 new  CGW Abrasives wheels from a reputable tool supply house in my area.


Before we move on to balancing, let me say that I re-machined the wheel mounting hardware that came with my bench grinder so it was flat.  I made new grinding wheel bushings for the wheels so they were mounted as true as I could get them.  I also trued up the wheels with a diamond tipped dressing tool similar to this one:

My bench grinder still vibrated.  It wasn’t serious, and didn’t affect the grinding of high speed steel tools, but it bothered me.  It was an inexpensive bench grinder, and I could go out and by a more expensive one, but most of the new ones all come from China anyway, and I was getting sick and tired of searching for sale posts for a good used Baldor for a reasonable price.  So I decided to see if I could at least make things a bit better.  I also know that surface grinding wheels are balanced when they are mounted.

First you need to know the mass of the entire grinder.  I used a baby scale that we have around the home.  Of course I had to remove the grinder from my grinding table.


I then determined the resonant frequency of my grinder.  To do this you need to mount your smart phone to the bench grinder.  I used zip ties, again.  You can see some of my other ‘cell phone’ engineering on my other page where I analyzed my mini mill using my smart phone:


Next step was to determine the  natural frequency of the system. With the grinder off, turn on your accelerometer app and tap the grinder with a dead blow hammer.  I exported the results and took a look at the response in Excel.  Here is what the chart:


Now you can see the wave is a little choppy.  This is due to my smart phone’s accelerometer limitations.  You could do much better with a higher quality accelerometer programmed using a micro controller (a Arduino works well!) but that wasn’t the point of what I was trying to do.  I wanted to see if my smart phone would provide useful information because it is easy to use!

From the graph I found the period of the vibration to be 0.032891 seconds.  The inverse of the period is the frequency, which is 30.403 Hz.  Note this is the damped frequency, denoted Wd.  From this point on some math is involved, you can view it in the spreadsheet posted below.  If you want me to detail the math used, send me an email.  Using the data the following was calculated:

Damping Factor 0.3890832
Natural Frequency 33.00449108 Hz
Natural Frequency 207.3733334 rad/s
Natural Frequency 1980.269465 rpm
Weight 39.996 lbs
Mass 18.18 kg
K (spring rate) 781807.2555 N/m
C (damping) 47.7799696 kg/s

As we can see, my bench grinder’s natural frequency is around 2000 rpm.  This means that it must accelerate through the natural frequency when it starts up.  I plotted the a startup of my bench grinder using my cell phone to confirm my results.  The very right of the chart shows the grinder running in steady state, or 3600 rpm.  You can see the response is stable and repetitive at the right hand of the graph.


Not so good!  Now this is a rotational imbalance problem.  Essentially a unbalanced mass is causing the entire system to oscillate.  This oscillate is the worst at the resonant frequency, but the unbalanced mass also contributes to the oscillation during steady state operation, in our case 3600 rpm.  Can we calculate what this unbalanced mass is?  Of course we can!

First we need to calculate what the response displacement is.  To do this you need to find the maximum, vibration amplitude during steady state.  My grinder had a maximum acceleration amplitude of 10.42 m/s^2 during steady state operation.  To calculate what the displacement is you need to divide this number (subtracting gravity first!) by the rotational speed squared (converted to radians per second).  You do all this and  found my displacement to be 0.004292 mm.  Once we have this, we have all the information we need to calculate what the unbalanced mass times radius factor (mR)  that is causing this vibration.

We need to solve the following equation where X is the displacement, mR is the mass x radius due to the unbalanced mass, M is the mass of the entire system, r is the frequency ratio and zeta is the damping factor:

Displacement_EquationAgain some math is involved, you can view it in the spreadsheet posted below.  If you want me to detail the math used, send me an email.  Using the data the following was calculated:

Max Amplitude 10.42 m/s2
Gravity 9.81 m/s2
Absolute Difference 0.61 m/s2
Rotational Frequency 3600 rpm
Rotational Frequency 60 Hz
Rotational Frequency 376.9911184 rad/s
Frequency Ratio, R 1.817934409
Displacement, X 4.29208E-06 m
Displacement, X 0.004292078 mm
Unbalanced Mass x Radius, mR 6.38521E-05 kgm
Unbalanced Mass x Radius, mR 0.063852078 kgmm
Radius of Required Mass 20 mm
Required Mass 0.003192604 kg
Required Mass 3.192603888 grams

So there, we now know how much mass we need.  Since I didn’t have any way to use my cell phone to figure out where the unbalanced mass was occurring  (this would require a some sort of method to determine phase of the wave from, such as a proximity sensor trigger), I decided to stick on trial weights and move them methodically around the wheels and watch the response on my smart phone.  After several tries I found a spot that was close to where it should be and proceeded to stick on the weights.  I used little washers, and I placed them on each wheel.

I used the following mounting tape:


I mounted the weights on each wheel, covered them with high strength tape, and let it sit overnight (according to the tape’s instructions) to harden up.


I put the covers all back on and started it up.  It ran much smoother, and my cell phone’s accelerometer showed significantly less vibration.  I couldn’t get the weights placed perfectly to get rid of all vibration, so some is still present.  But it is a lot better than it was.



I plotted the results of my grinder starting up and overlaid them over the results before I added the mass:


That looks a lot better!

In the future I am going to try to come up with a simple way to measure phase.  This might involve a computer instead of a cell phone, but for now I’m much happier with my bench grinder.   When it accelerates and decelerates it is much quieter and during operation you cannot tell it is running.  Hey, its not a Baldor, but it works like one now!

You can view the spreadsheet I used to do the calculations: BenchGrinderAnalysis.