5C Collet Chuck

A few months ago I purchased one of the popular import 5C collet chucks for my home shop.  I’ve been investigating different ways to employ a proper collet setup in the home shop for awhile.  At first I was considering going the ER collet route and purchasing, or making, an ER collet backplate for my lathe due to the large grip range of ER collets and that they are very plentiful.  From a manufacturing engineering standpoint ER collets are not considered proper work holding collet, being designed specifically for tooling, but they actually do a good job in the home shop for work holding provided you are aware of the short comings:

  1. ER collets are generally not available in square or hexagon.  This isn’t as big of deal as it may seem – many folks use ER collets and simply grip on the the edges of non round stock.
  2. ER collets require more grip length than almost all work holding collets.  This is probably the biggest downfall to using ER collets in the home shop.  Holding onto a very short part in an ER collet in most cases is asking for trouble.  Even more sketchy would be holding onto just the edges of short square or hexagonal parts in an ER collet.
  3. ER collets require relatively high tightening torques.  This isn’t a big deal with the smaller sizes, but once you get into the larger sizes (greater than ER20) it becomes a pain.  For example ER32 is recommended to be torqued at 100 foot pounds!
  4. No emergency or soft collets available.  I suppose you could make up some soft ER collets fairly quickly though.
  5. No ER pot chucks, clutch collets, step collets, oversize collets, or whatever you want to call them.

Most of the above reasons are relativity minor when comparing ER to standard work holding collets.  Many of the above downfalls of ER collets are offset, especially when you are starting out, by the fact that you can use ER collets and collet chucks for both work holding and tool holding.  ER collets also have a very large grip range – meaning you need fewer collets to cover a range of sizes.  This can save money on tooling, which can be a big deal in the home shop and was precisely why I was seriously considering using ER as I already had a some collets in the shop.  When you consider you can purchase the ER collet backplates for less than $100 or make them easily in your home shop it’s a logical choice.

But I decided to go with a standard work holding collet, mainly for reasons 2 and 5.    I chose 5C as it is by far the most popular work holding collet available.  There is a plentiful used market and new collets are inexpensive.  Soft and clutch collets are inexpensive and I can get them next day from a local tooling supplier.

There are a few options for the actual collet chuck.  Import ones are available from numerous suppliers for below $200 and this is the route I went.  I actually ordered it off Amazon Canada.    If you are looking for something of higher reputation (note generally most of the import one are actually decent) you can purchase a standard accuracy Bison ones for around $500 with a stated .0008″ TIR.  A super precision one is available for $900 with a stated .0004″ TIR.

My import 5C collet chuck has less than .0008″ TIR, which is less than the stated accuracy of the standard Bison one at less than half the cost.  It is very well finished and so far works exceptionally well.  I have ordered inexpensive $12 emergency collets for it, and also I have been using it with a custom bored 3″ pot chuck recently for a repetitive job.  With careful loading I was indicating less than .0005″ runout on this job.

A few weeks ago now I also made a video of the chuck, including some of the mounting of it on the 2 lathes in the shop.  I recommend people to get a standard backplate one and either make up your own backplate or buy one.  By mounting the chuck on a backplate it gives you an interface to adjust the TIR to zero – if the mounting system is directly manufactured into the chuck your options are probably limited to regrinding the taper in situ to improve accuracy of the chuck.

If you are a more of your make your own tools type Andy Lofquist over at Metal Lathe Accessories has an interesting 5C collet chuck kit that you can machine yourself.

 

Diamond Dresser

For Christmas a few months ago I made a diamond dressing tool for my brother in law.  He is a woodworker and uses his bench grinder for the initial sharpening of various wood working tools.

The tool is made up of 4 parts.  The body is a piece of steel with an angled lip (one on each side) that is used as a guide against the tool rest on the grinder.  It has a threaded hole for the diamond.  The diamond is an industrial diamond held in a steel rod – commonly used in surface grinding dressers, modified with threads along most of its length.  There is a lock nut and o-ring (to provide some cushion when tightening the nut down) and a handle nut to adjust the distance from the lip to the edge of the diamond.

The tool is useful for most sizes of standard bench grinders as the body has 2 different lip offsets.  The threaded diamond is also allows for generous positioning.

After giving him the tool I explained a few of the benefits of such a tool versus a traditional spur style tool:

  • The amount of grinding wheel material removed is easily controlled as the distance on the single point tool is adjustable.
  • A single point diamond tool does a better job at getting the wheel round in the first place.  This is because the forces involved are significantly less than traditional spur type tools, or even the newer T style diamond tools.  Forcing traditional tools up against the wheel isn’t a very steady process and the entire tool floats on the surface of the wheel.  In addition your hand can move back and forth with the high and low points on the wheel.  As such I’ve found single point tools create a wheel that is rounder, which helps with balancing.  (Grinder balancing always happens after a wheel has been dressed).
  • Unlike spur tools or the cheap T style dressers a properly used diamond tool lasts a long time on a bench grinder and also is very durable for various wheel materials.

After Christmas I finished up a tool for Max over at the Joy of Precision:

I made up a full set of drawings of the tool if you would like to make one yourself:

Body – (Rev 01) Diamond – (Rev 01) Handle Nut – (Rev 01) Lock Nut – (Rev 01) Dressing Tool – (Rev 01)

I’ve also had a fair bit of interest in people asking if they could buy one of these tools.  I’m making up a number of them for others so if you are interested send me an email: justin@thecogwheel.net.  I’ll be posting additional information shortly.

As usual I made up a video of making the tool and it also shows how I use it:

 

 

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:

  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:

 

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: