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:

The process is very simple:

  1. Thoroughly Clean parts using a good degreaser.  This step is very important!
  2. Etch parts in acetic acid (common household vinegar)
  3. 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.
  4. Fully submerse parts in boiling water and watch red rust turn to black oxide.
  5. Lightly wipe or wire brush parts.
  6. Repeat steps 2 through 5 until you are happy with the coating.
  7. 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.

$200 Shenzhen DRO (JCS900-2AE)

About 6 months ago I purchased a digital readout off eBay for the Rong-Fu mill drill. Originally I had planned to purchase either iGaging scales or standard import calipers and utilizing a tablet based DRO. Once I started looking at prices however I was shocked to find that for less than the price of either the iGaging scales or the import calipers I could have a full blown 2 axis DRO complete with proper glass scales.

I went ahead and ordered the scales off a eBay seller. It was a typical Chinese eBay seller that sells everything from DROs for machine tools to various useless cell phone and house gadgets. The total for the order was around $200 USD plus about $30 for shipping. I then communicated the scale lengths I needed via email. In about 2 days I had a shipping confirmation including a tracking number.

I was excepting to wait about 3-4 weeks for the shipment to arrive, typical of most stuff ordered from China. I was shocked at the end of the week when I received an email from DHL that my shipment was to arrive on the following Monday – about a week for the entire process! Sure enough Monday afternoon a DHL driver dropped off the 2 boxes.
The one box contained the DRO – a JingCE JCS900-2AE 2 axis DRO unit. The other box contained the 2 glass scales both of proper length. Also included was a large amount of hardware, mounting brackets and associated items you would need to install the DRO.

I spent the next few days thinking about how to mount the scales. The X axis was easy – I decided to mount it to the front of the table using the T slot already present. I thought about mounting it to the back of the table but I didn’t want to loose any Y axis travel. The Glass scales are rather bulky – something to note if you are considering installing them on a smaller mill like the X2 mini mill. The Y axis was a bit of a different story – there really isn’t anything to fasten the scales to. I decided to make up a bracket to hold the Y axis scale. That took a fair bit of work to do.

Y Axis Scale (behind the fabricated bracket)

X Axis Scale

After mounting the scales and trying out the DRO I also fitted a inexpensive import digital caliper to the quill to get a .001″ resolution readout for Z depth. This also took a few hours to do properly. 2 brackets were made out of aluminum to hold each end of the caliper. I modified the caliper using a Dremel tool. I drilled mounting holes using a standard off the shelf masonry drill bit – a poor man’s way of drilling hardened steel. High speed steel usually won’t touch hardened calipers.

Hard Drilling Using a Masonry Bit

After using the DRO for 6 months I can say that it is a very good unit. I haven’t had any issues. As far as accuracy and repeatability is considered, I really don’t have the proper measuring tools to qualify the DRO but I will say that I tested it using a dial indicator over the travel of the table. At each point where I tested the DRO it corresponded to the dial indicator – within at least .0005″ (as best as my judgment permits). I also ran the table up against a hard stop several times to test the repeatability and each reading was easily within .0005″. I probably should do a proper gauge R and R study on it, but just with the general testing I’ve done it’s easily within .001″. And to be honest doing work closer than .001″ on a Rong Fu mill drill is unreasonable.

I filmed and edited a number of videos showing the install and finally a video review of the DRO.  The first video shows the hard part: the installation of the Y axis scale.

The second video shows the installation of the X axis scale and also the mounting of a digital caliper on the quill.

The final video is me talking about the DRO itself and contains much of what is written here.

If you are interested in reading the manual, I scanned a copy of it and it is available here.

One thing to note is that you will get little to no support with the DRO. To me this isn’t a big deal at all when you consider the price. The next closest DRO in price in the North American market is approaching 4 times the cost. And the unit looks suspicious like this unit. If something breaks I am willing to try and fix the unit myself or simply replace it.
If I had a high end knee mill I would probably buy a Mitutoyo DRO and be done with it. But putting a Mitutoyo DRO on inexpensive import mills is a bit like putting lipstick on a pig.

It was a $200 well spent. Having a DRO on a milling machine is exceptionally handy. I won’t say it is a necessity, but it greatly improves your efficiency – especially on larger mills or making larger parts. Time will tell how durable the unit is but I think it is an excellent addition to a home metal shop.

Home Shop Machinists Podcast – Episode 15 – Snowed, Towed, and Tooled

If you are just starting out in your home shop or need a few ideas for your next project you will certainly find it in this episode.  After getting through the craft beer podcast and shop updates, which involve Max getting a tow, Max and Justin talk about useful simple shop tools as well as Tchotchkes and probably everything in between (don’t tell us you’re surprised!).  In the process both Max and Justin have extended their shop project lists.  You could even make a really nice homemade brake line flaring tool (we won’t talk about liability):

Some of the interesting links:

You can listen to it directly here:

or you can download it directly.

Subscribe in iTunes (and please rate us!):

Max’s website: The Joy of Precision and also his Youtube channel: Max’s Instagram:

Justin’s Youtube channel:  Justin’s Instagram:

Home Shop Machinists Podcast – Episode 14 – Phillipsed

When one Phillips isn’t enough.  Recorded in between years as Stefan would say, Max invites his brother Thayer and his father Fred on to join in an end of year discussion with our new semi regular co-host Stefan Gotteswinter!  In this episode we talk about:

  • Fred’s shop that Thayer works out of.  Fred has a really nice Rockwell mill (one of our all time home shop favourites) and a Southbend Heavy 13.
  • We talk about gunsmithing in the United States, Germany and Canada
  • Live free or die!
  • CAD and Stefan’s embrace of Autodesk Fusion.
  • Stefan machined some really nice Torx screws using his Deckel pantograph.
  • Justin is busy making Christmas presents.
  • Stefan wants to get a CNC lathe in 2018.
  • Max is hoping to finish his Trent pinion mill.
  • Both Max and Justin are hoping to get back to semi regular posting on Youtube.
  • And finally cars.  Max is hoping to get some German iron.

You can listen to it directly here:

or you can download it directly.

Subscribe in iTunes (and please rate us!):

Many thanks to Fred and Thayer for joining in!

Many many thanks also to Stefan for coming back on and agreeing to become our third co-host!  We hope to get Stefan on much more frequently in 2018.  You can find his website here:  Stefan also has one of the best machining Youtube channels: Instagram:

Max’s website: The Joy of Precision and also his Youtube channel: Max’s Instagram:

Justin’s Youtube channel:  Justin’s Instagram:

A final note regarding the live stream with Robin Renzetti and Stefan Gotteswinter.  We are still hoping to do this in the next few weeks.  Stay tuned for more announcements!