Shop Made Yo-Yos

Over 6 months ago now I finally finished a pair of yo-yos I made for family friends who gave us a wagon for our kids. The wagon was a very well made wagon and I wanted to make a special gift for the family in return. I remembered how much I enjoyed yo-yos when I was a kid so I decided to make up one for each of their 2 girls.

The design is very straightforward. Essentially it is 2 aluminum halves with a tool steel axle. I chose to make the bearing / bushing out of some Teflon I had in the shop. You could easily modify the design to use the very common rolling element bearings that so many yo-yos utilize these days. The trickiest part of the design is sizing the o-ring that sits in each of the halves. The size and cross sectional area of the o-ring used determines how easily (if at all) the yo-you will return to your hand. If you remove the o-ring completely the yo-yo may never return to your hand and probably will require what is called a “binding” trick which causes the yo-yo to recoil its string. Since I wanted these yo-yos to be easy to use for beginners I sized the o-ring so the yo-yo will return with a easy flick of the wrist.

The project made heavy use of the 5C collet chuck that I previously reviewed. The chuck worked out very well and the soft 5C collets that I used made the job much easier and quicker than it would have taken using the old 4 jaw standby.

I chose to press in 12 pieces of brass on the outer rim for added mass where it is needed most. Besides making up 48 pieces of brass for 2 yo-yos the process was very easy. After the brass was pressed in I cut the outside radii with a custom form tool I made up in the shop. I also made a video of making the form tool. You can watch that video here:

Besides the custom form tool for the radii, there were a number of other tools I ground up to make this yo-yo. The project once again highlights the basic home shop need of being able to grind high speed steel tools. If I had to purchase all the cutting tools I needed for this project the cost would have been significant.

I also did a full build video of the process. Many thanks to Megan for recording music for the introduction.

If you are interested in the drawings you can download them here:

Body – Rev 01, Bushing – Rev 01, Axle – Rev 01, Yo-Yo – Rev 01.

Vise Clamps and 1 Hour Red Rust Bluing

Let’s rewind to the summer when I purchased the Rong Fu milling machine for the shop. The mill included an exceptionally well made French made Sagop milling machine vise that had a bit of wear but was very usable. Up until this point I have never heard of Sagop before.

A quick search revealed a basic corporate webpage. It appears that Sagop is still in business and still manufactures a line of workholding products. The vise that I purchased is the smallest of their precision CNC milling vises, a 100mm 800 series vise. The construction of the Sagop is very similar to the Bison precision CNC milling vises. I was also floored to learn the purchase price of this vise. It is listed over 1000 euros with the swivel base – a number that is rather shocking when you consider that it is sitting on a Rong Fu milling machine!

The vise came with the swivel base – a very well made turntable base that allows for 360 degree rotation. A very handy feature in some situations, but for most of the work that I do I usually just bolt the vise directly to the table. This takes up less table space and is also more rigid.

Strangely the vise did not come with any way to mount it to the table. Up until this point I had been using some of those standard import clamps that are sold everywhere. This wasn’t the best solution as these clamps are quite bulky and don’t do the best job of holding in situations like this. So set out and designed up some new clamps to be made.

But first I searched to see if I could find drawings of the vise and / or the swivel base, not only for this project but for future ones. While not directly advertised on Sagop’s website, I managed to find the drawings for the vise and the swivel base:

Sagop 800 Series Vise Drawing Sagop 800 Series Swivel Base

I modeled the clamp up in Fusion and made up a drawing of it based on the dimensions I found in the above pdfs. Now some folks at this point say CAD is a waste of time for such simple projects, and it maybe for them. But I’m actually quicker at modeling something up in CAD than I am drawing up a sketch on paper so for me I usually start with a 3D model.

The clamps are designed for 3/8 cap screws. I then made up a shop drawing for the clamps:

Sago Vise Clamp – (Rev 01)

Making the clamps was a very straightforward process. The most interesting part was when I used the 4 jaw chuck in the lathe to counterbore for the cap screws – I haven’t invested in any counterbore tools yet for cap screws. I need to quit being so cheap.

When they were finished I started to wonder about how I was going to prevent them from rusting. Rust is a very real problem in home shops, and in particular my shop as I live in a climate that is somewhat humid and has significant temperature swings. If you are willing to deal with plating shops you might be able to find a shop to do a zinc coating – but for small one off parts it is often impossible on a budget as most plating shops have a minimum charge that far exceeds what home shop machinists can afford.

I have considered cold bluing products in the past as a simple method to provide some rust protection on parts. In Canada cold bluing is a bit harder to procure than south of the border, and is is also somewhat expensive. So I started to read up on other processes. Hot bluing looked interesting, but involves some nasty chemicals. Rust bluing looked promising but it seemed like a long process – you had to wait around for the rust to happen.

I did some more reading and I recalled an experiment we did in high school chemistry involving a mixture of hydrogen peroxide and salt applied to steel wool. The hydrogen peroxide and salt rusted the steel wool so quickly that you could measure the temperature change. I then did some further searching and I found a fellow Canuck who beat me to the idea of quickly rusting parts using hydrogen peroxide and salt: https://mypeculiarnature.blogspot.ca/2014/08/quick-rust-bluing-back-in-black.html

The process is very simple:

Thoroughly Clean parts using a good degreaser. This step is very important!
Etch parts in acetic acid (common household vinegar)
Rust parts using a warm hydrogen peroxide salt mixture. You can either fully immerse the parts or brush the mixture on. I mixed it up about 1/4 cup peroxide and 2 tablespoons of salt.
Fully submerse parts in boiling water and watch red rust turn to black oxide.
Lightly wipe or wire brush parts.
Repeat steps 2 through 5 until you are happy with the coating.
Dry parts and oil

The final result is a nice black oxide coating that helps protect against rust and looks great:

I made a video of the process, including the making of clamps:

Cross Slide Screw Support

A few weeks ago I finished a project that I had on my mind for a number of months. There was a lot of play in the cross slide feed screw on my import bench lathe. This showed up as backlash in the feed screw – when you grabbed the toolpost and applied force in alternate directions you could see the entire cross slide move back and forth. Some of it was from backlash in the feed nut itself, but most of it was between the feed dial and the support casting itself.

I tried tightening up the nuts themselves tor reduce the amount of clearance – but then it bound and you couldn’t turn the feedscrew at all. This wasn’t the best design from the get go.

The first thing I did was modeled the entire assembly up in Fusion to get a clear picture of what was going on – and to give a good starting point for the modification: The nuts aren’t shown on the end of the feedscrew but you can see where the assembly is constrained for axial movement – at the right side on a shoulder machined into the feedscrew itself and on the left side the inner bushing of the dial. These are just 2 plain bearing surfaces – and they weren’t machined the best to begin with. No wonder it wasn’t the best!

I thought about doing what Stefan Gotteswinter did. If this was my main lathe I would copy what Stefan did as it is the best solution by far. Angular contact bearings are the way to go in this situation. Since I’m keeping this lathe around primarily for cutting metric threads (the Standard Modern now in the shop doesn’t have a metric transposition gear) I decided to scale back the project and see if I could just stuff a deep groove axial bearing and a roller thrust washer into the space without having to modify the leadscrew, or make up a new dial.

Below is what I came up with:

I incorporated a deep groove ball bearing (6900-2RS) and a 10mm needle style thrust washer on the opposite side. This required a new housing and the old cast iron bearing support to be shortened up. The new housing was doweled to the cast iron block for location. 2 counter bored cap screws hold the entire assembly together. The cross slide screw required minimal rework – a shoulder had to be turned for the bearing to sit against. I also turned down the shoulder on the screw that previously was a bearing support.

The ball bearing is preloaded using the existing nuts. Care needs to be taken not to overload the ball bearing as deep groove ball bearings aren’t primarily designed for axial load. In retrospect I should have flipped the positioning of the deep groove ball bearing and thrust washer around when thinking about cutting forces as the cutting tool pushes away from the work piece. If I have problems I can always make a new bearing housing.

The cross slide now is super smooth with no backlash due to the support. There is a bit of backlash in the screw, but I don’t get too bothered by that on a manual machine. It is significant improvement with not too much effort or time required.

I made a video of the entire project as well:

Tailstock Die (and tap) Holder

A few months ago I decided I had enough with using my traditional die holder in the lathe and set out to make a proper sliding die holder. It is a very good beginner project that is straightforward to make and also is one that is exceptionally useful.

I started out with a design in Fusion. The design consists of 3 manufactured parts, a body, an arbor, and a handle for extra leverage. The body is designed to hold 1″ dies – a size that I have standardized on in my shop due to primarily expensive. As die sizes climb the prices move up exponentially and due to that I generally single point large threads. If you have larger dies the design is very easy to modify to accommodate larger dies.

Traditionally most people don’t use a sliding die holder to hold taps. I’ve always started taps in the lathe using the tailstock. If the tap is small enough I am brave enough to power tap – being sure to leave the tap a little loose to make sure when it bottoms out it slips to avoid broken taps. I had the thought to incorporate an inexpensive ER collet chuck into the design to facilitate holding taps. In this design the ER16 collect chuck stub is held in the end opposite to the die holder with a couple of set screws.

Besides being a pleasure to use with dies, it also works exceptionally well for small taps. I don’t use the handle when I power tap with it – the handle is really only used for dies. Now when you are tapping blind holes you can simply let go of the body and the entire body spins. You can also feel when the tap reaches the bottom of the hole as the amount of force required to hold the body quickly climbs – at this point you simply let go, allow the body to spin and shut the lathe off.

Standard ER collets do a very good job of holding taps in the home shop. You can get ER collets with an internal square that engages the tap drive but I’ve found it unnecessary for home shop work. They are also more expensive and harder to find online – most industrial tool supply places can get them.

If you would like to build one yourself I made up a full set of drawings for the shop, and I’ll also provide 3D CAD in the zip file (iges and step):

Handle – (Rev 01), Body – (Rev 01), Arbor – (Rev 01), CAD – (Rev 01)

I also made a video the project:

The Future is Here: Introducing a Laser Bandsaw

A few months ago Max and I recorded a podcast where Max and I theorized on the what the home metal shop of the future would look like. The podcast idea was inspired by the Making It podcast hosted by Jimmy Diresta, Bob Clagett and David Picciuto where they talked about what they think the future maker workshop will look like. During the podcast Jimmy, Bob and David mentioned the idea of a laser bandsaw – something that Max and I also talked a bit about on our podcast.

A month or so after the podcast Rod Shampine reached out to me to talk shop over the phone one night. I had a very enlightening conversation with Rod, who is an exceptionally gifted mechanical engineer with over 50 patents. Rod also has his PhD and has worked on some exceptionally interesting projects – both on the job and for hobby. He is an active home shop machinist as well. Over the last few years Rod has done a significant amount of work in the 3D printing world – he is very active on Thingverse and also has did a significant amount of work on 3D printers themselves.

In the conversation Rod told me he had acquired all the hardware to put together a laser bandsaw prototype. At first I thought he was making a joke, but he went into specifics about safety, power supplies and the actual laser itself. Rod certainly had a workable design flushed out – one that both had us very excited.

In December Rod sent me an email that he had finished his laser bandsaw. It could only really cut paper and balsa wood but to my knowledge it is the first working prototype of such a device. Obviously a laser bandsaw is exceptionally hazardous – particularly to your eyes. Rod pointed this out numerous times. But with proper eye protection and proper design a device could be made to work.

Shortly afterward Rod posted his working prototype on Youtube:

So thanks to Rod the future is now here. I’m watching with interest to see where this all goes.

Shop Made Quick Change Toolpost

A few weeks ago now I finished a quick change toolpost for the Schaublin.

The design is based on Andy Lofquist’s MLA-23 toolpost. Andy is the man behind the wonderful Metal Lathe Accessories kits (http://www.statecollegecentral.com/metallathe/). While I’ve never ordered any kits from Andy, I’m told that they are very high quality and are exceptionally thought out.

After quickly considering a Tripan toolpost and changing my mind after I saw the prices on those I ordered a set of drawings for the MLA-23 toolpost. The original design is for 9″-12″ swing lathes. The Schaublin is an 8″ swing lathe. After drawing up the original toolpost in Fusion and drawing up the Schaublin cross slide it was evident that it was too big. I decided to design a scaled down version, making some changes along the way.

The largest change is in the dovetail size and the shape of the body itself. I wanted something that would match the Schaublin’s size, but also look, so I manufactured the body out of round material instead of square. The toolpost is optimized for 1/4″ HSS tools, but 5/16″ will fit.

The internal workings are that of the MLA-23 toolpost. The design is exceptionally rigid and works very well. It is also a wonderfully simple in design. Part of the reason I really like this design is for its simplicity. I believe the best design is one that doesn’t allow you to take anything away. This design, in my opinion, is one of those designs.

Some people don’t like that the toolpost doesn’t repeat in angle position – that is once you loosen the locking handle you completely loose the rotational position of the toolpost. This is a downfall of the design if you truly need rotational position repeatability. When I work in the shop I’m constantly moving the toolpost around to allow for tool clearance. So much so that I made a handle for my Aloris clone on my 10×18 lathe a number of months ago. I do have provisions in the design to allow for graduations on the base to allow for visual rotational positioning. We’ll see if I add it.

The build was interesting and fun. I learned a number of things along the way including how to cut dovetails on the shaper. It took a bit of time, but it reaffirmed the very useful nature of having a shaper in the shop. Instead of waiting for a dovetail cutter I could grind up a simple tool and cut nice dovetails, at any angle, and get a super finish. I’m told you can build the entire toolpost with a lathe, but there is a fair bit of milling work so even a mini mill would be a huge help.

Since the design borrows heavily from Andy’s design I don’t want to release drawings. What I’m planning on doing is forwarding a set of drawings to Andy to include with his prints if he is interested. So if you want to build the smaller version, which is a perfect size for the mini lathe, send me an email and I’ll try to get you a set of drawings.

I made a build video of the entire toolpost in montage style format as well.

Pentel P209 Teardown

wrTie has begun!

To start off my titanium mechanical pencil build, called wrTie, I decided to teardown a number of different mechanical pencils for inspiration and design ideas. I find the mechanisms in mechanical pencils very interesting. I also find the manufacturing processes that are used exceptionally interesting.

Here is a teardown video of my favourite mass produced mechanical pencil: the Pentel P209 (0.9 mm version). The Pentel P20x series (there are 0.3, 0.5, 0.7 and 0.9 mm models) has been around for a long time. It is exceptionally well made given the price point it is hitting and the parts involved. There are 12 parts in total, including 5 fully machined parts. A number of the parts require plating. There are 2 parts that are molded out of plastic. And then it has to be assembled! You can buy a Pentel P209 for less than $5 in the United States and less than $7 in Canada. That’s actually pretty crazy considering this pencil contains machined parts and even more so once you consider that Pentel is probably selling it to it’s retailers for less than half of what they are retailed for.

https://youtu.be/tM4h61_BLKQ

The heart of the Pentel 200 series is a removable fully contained feeding cartridge. The cartridge features a number of machined components in the feeding mechanism. The components are probably massed produced on swiss style screw machines (a lathe but instead of the carriage moving the spindle moves in the Z direction – often called sliding headstock machines). These machines could be cam actuated screw machines or they could be CNC controlled units. CNC swiss style machines, like the ones produced by Star or Citizen, are really interesting machines. Here is a video of a Citizen L20, one of the more popular CNC swiss machine that you will find today:

The Pentel P209 cartridge has been used in a number of titanium mechanical pencil builds on Kickstarter. I can’t confirm it directly as I haven’t purchased one, but check out this project (you have to scroll about half way down and you’ll see a picture of what looks to be the Pentel cartridge: https://www.kickstarter.com/projects/cogent/titanium-mechanical-pencil-and-titanium-pen. Given the Pentel’s design, you could easily make a new mechanical pencil by machining a new outside body for the Pentel. I won’t be doing that because I think it is too easy!

Terrible Design 101

Recently I had to fix a toy for the new addition in the family. It was a car seat toy. The toy is suppose to play a song when you push the dog’s nose. We’ve had this toy for a few years and all it needed was a new battery. I made a short video going through what I needed to do to change the battery.

I hate tamper proof screws. The only point to them is to either sell more tools, or force people to throw stuff out. They don’t keep people out. People who want to get in will get in, and people who don’t want to will not. And keeping people out of products so they can’t change batteries doesn’t make any sense whatsoever. Then there is the problem of end of life. How many people would just chuck this item into the garbage?

End users or consumers should always be able to remove and replace batteries without the need for specialty tools so they can remove the batteries before they dispose of the device, or prolong the life of the device. Why is this such a big deal? Devices with non removable batteries cannot be automatically processed by waste recycling facilities (because these facilities grind up the entire device – which would cause major issues with batteries). This forces these types of devices to be shipped overseas where low cost labour disassembles them. Often kids are doing this work, and the waste is not disposed of properly.

Apple is one major manufacturer that insists on fully enclosed non removable batteries. This is terrible, but it helps their agenda: sell more devices or sell more over priced service. Numerous reasons are given for built in batteries in small electronic devices, but in reality they don’t have any merit. I have a inexpensive ($100) Android phone with a removable battery and it works great. And if the battery needs to be replaced, I don’t even need any tools to replace it. And when the device fails I can remove the battery and send them to appropriate recycling facilities, instead of across the globe.

We really have to stop designing for the dump and quickest assembly, and start designing for service and longevity.