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:
- 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.
- 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.
- 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!
- No emergency or soft collets available. I suppose you could make up some soft ER collets fairly quickly though.
- 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.