Er 40 Collet Chuck And Spanner Wrench

Mark_f

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I had posted some of this in Project of the Day thread, but decided to put the whole thing here as a project. Many have made their own collet chuck and I decided it was time I moved into the new century and started using collets for convenience mostly , but also for easy accuracy. I bought a 23 piece set of ER 40 collets from 1/8" to 1" by 32ths. I next started my chuck. This is a simple project and only takes a few hours to make. Yes , I screwed the first one up learning to do metric threads on my South Bend lathe and had to make the chuck over again.

The first step was to chuck up a piece of 2 1/2" diameter round stock , 3 inches long and drill a 1" hole all the way through. I then bored for my spindle thread and threaded the end 1 1/2-8 to fit my spindle. I didn't bother to document this step as it is simple machining.
ER40 collet chuck 1.jpg I screwed the part on my spindle , but first, I went to the drill press and drilled a 1/4" hole for a pin wrench. This is important (I learned this the hard way :( ). I you don't do this it will tighten up on the spindle while machining and you can't get it back off without messing it up with the pipe wrench :oops:. I next machined the outside so it is true, smooth , and shiny (I love shiny things :grin: ).

ER 40 collet 3.jpg I set my compound at 8 degrees. It is important this is accurate, so I set up two indicators on the compound. 8 degrees equals a taper of .1415" per inch of travel. When my one indicator showed 1" of travel and the other indicator moved .1415", I was set at 8 degrees. I used a boring bar and bored the taper until the outside opening was 1.610" I then mounted my Dremel on my lathe and ground this taper using the compound still set at 8 degrees. The photo shows the finished taper.
I purchased an ER 40 collet nut on eBay for $12. I turned the end of the chuck to 1.968" diameter and threaded it at a 1.5 mm pitch to match the nut.
ER 40 collet chuck 5.jpg Here is the finished collet chuck. This whole process from start to finish took about 5 hours. I am well pleased with it. It is within .0005" true. I am happy with that. NOW THE PROBLEM. I found I need a good spanner wrench to remove the chuck and to hold it wile tightening the nut. I put a 1/4" rod in the hole and it bent . the darned thing is stuck. I don't want to mess up the pin hole ,so a spanner pin wrench is needed. One this size costs about $50 :eek:, so we gonna have to make it. I ain't payin that!

I had ann extra finger from the bending brake so I used it . it is 3" wide and 7" long. The first thing to do is mill a half round notch 2 1/2" diameter.
spanner wrench1.jpg
I put the steel in my mill and rough milled a notch by going back and forth a few times inside the line I drew. Kinda rough.
spanner wrench2.jpg
Next, I start at the left edge and by turning both axis hand wheels at the same time, I follow the line to mill the curve. This is a skill I was taught early as a machinist to make odd shapes, like a half circle. This was my first pass after roughing. I will do one more to get it even smoother.
spanner wrench3.jpg After the mill, I dressed the curve on the top wheel of my belt sander. Here it is mounted in the band saw to cut off excess material.

spanner wrench4.jpg
The inside of the spanner wrench is finished. this process to this point took about an hour.

spanner wrench5.jpg
I laid the wrench on the chuck and marked where to drill the hole for the pin. Tomorrow , I will cut the outside shape , drill and install the pin and make a nice handle. So.... keep watching. The wrench takes about three hours from start to finish but will be nicer than anything I could buy.

I got a really heavy and nice wrench for the collet nut for $10 from the same folks that sold me the nut.
 
Next, I start at the left edge and by turning both axis hand wheels at the same time

I have never been able to do that. One hand always went the wrong direction.
great job

Ray
 
I have never been able to do that. One hand always went the wrong direction.
great job

Ray
It takes practice and concentration :grin:. maybe being left handed helps.:rolleyes: My mentor made me learn to do it many moons ago on a Bridgeport.
 
I finished my spanner wrench.
finished spanner wrench.jpg This is the finished wrench. I used the shank of a broken 1/4" end mill for the pin. it is very hard. I rounded the edges of the handle for comfort. I think I will dip the handle in some Plastic-Dip . I cut it all with an end mill. Took about 15 minutes to cut the outside and handle.

fits chuck good.jpg The wrench fits on the chuck very well.

both wrenches.jpg This is both t he wrenches for the chuck. I bought the nut wrench from Bolton Tools for less than $10. It is heavy , about 3/16" thick. I couldn't make it that cheap, this nice.

This project is done and I am very happy with the collet chuck.

ER40 collet chuck 1.jpg
 
The more of these I read about, the more I want one. First I need to get some ER-40 collets :distrust:
Good Job :eagerness:
 
do you use the chuck wrench you made to hold the chuck while loosening the collet nut? If so, does it work ok being somewhat one directional?
 
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