Latest Project - Finished: a 5C Collet Closer

[jgedde]

Here are some pics of my latest project all finished. It's a 5C collet closer for my Grizzly G4003 lathe.

I worked on this all weekend and my wife is ready to kill me. She's calling me "mole man" since my shop is in the basement.

In any case, it included a plethora of lathe techniques: internal blind threading, metric threading, knurling, machining tapers and more. I had never done metric threading, internal threading, or precise taper turning before.

The collet adapter is made from steel (unknown type). The collet thread piece is 303 stainless. The draw tube is black iron pipe. The outboard spindle thrust collar is nylon. The handwheel is 6061. Apart from that, all else that's there is a roll pin to lock the handwheel to the draw tube and a 3/16 brass pin to lock the collet draw onto the draw tube.

How I managed to make all those pieces without any uncorrectable mistakes or blood is beyond me. +++ I'm usually not so lucky.

Here are some pictures:





John

 

[Pauls77]

Outstanding job!

Ideally, you'll want to add a dog-point in the side of your adapter to capture the groove that's down the side of the 5C's body to keep it from turning. I also question how long the nylon will hold up, but easy enough to fit a real thrust bearing later.

Be sure to pick up some Brass, or even Nylon, un-machined "Emergency" collets if you see them on sale, real life savers for some jobs.



PaulS

 

[jgedde]

Hi Ed,

Thanks for the good words. The adapter is indeed made from one piece. That groove has some rust and dirt down in it that looks like mill scale as that part was partially made a while back and was not stored well. I never bothered to clean it up - but now I just might! ===

The brass pin holds the 303 internal threaded "collet grabber" onto the draw tube (it's also press fitted). This is a permanent assembly. The roll pin is used to hold the handwheel onto the draw tube (removable so as to be able to replace or retrofit the thrust collar).

See attached picture showing both pins.

John

 

[jgedde]

author=Pauls77 link=topic=3630.msg26484#msg26484 date=1316446737
Outstanding job!

Ideally, you'll want to add a dog-point in the side of your adapter to capture the groove that's down the side of the 5C's body to keep it from turning. I also question how long the nylon will hold up, but easy enough to fit a real thrust bearing later.

Be sure to pick up some Brass, or even Nylon, un-machined "Emergency" collets if you see them on sale, real life savers for some jobs.

[attachimg=1]

PaulS

Thanks Paul.

There is a drive pin down inside the adapter to pick up the groove in the collet. As far as the nylon, that was my though exactly about durability. Easy enough to make a new one. But, I had the nylon in the junk box (along with everything else) and the aluminum thrust surface is polished to minimize galling. The nylon is nice because it is slightly "sticky" and acts sort of like a anti rotation device to prevent the collet from unexpectedly loosening. It's also slippery enough to act as a bearing.

BTW, the brass pin I used came from the "goodie bag" you gave me at our MOLI get together at your shop.

John

 

[Pauls77]

John,

One way to clean up the weld seam inside of black pipe is with a suitable size/length of broom-handle/wood dowel, and a half-round file.

Cut a file-length flat in the middle of the side of the wood broom handle, sized to capture the half-round file laid flat on it. Then hand run the pipe over the broomstick/file, maybe hold the broomstick in your workbench's vise for this.

Shim up the file with some cardboard or something suitable, and repeat running the pipe over the file/broomstick until the inside of pipe is clean of the seam.

Ideally you'll want to be able to pass the full 1-inch capacity of the 5C's through your drawtube.

Have fun.

PaulS

 

[jgedde]

author=EdK link=topic=3630.msg26494#msg26494 date=1316451337
John,

That picture clears it all up. Where did you get the schedule 80 black pipe and what is the length of the piece you used? All the home centers carry in my neck of the woods is the thinner walled schedule 40. I suppose one could get it from a plumbing supply house.

Thanks,
Ed

The piece started life as a 26" length of pipe I found in the cut-off pile at Home Depot - it might well be schedule 40 (which would be mechanically sufficient) I can't tell you exactly what the finished length of the tube is because I deliberately made it longer than was required so as to be free to position the handwheel where it needed to go to allow the collet to start, have good tightening range, but also not allow the adapter to bottom out on the collet grabber (in use, there's always a gap between the back of the adapter and the grabber). In other words, I designed it to pull against the outboard side of the spindle rather than pull the collet in by bottoming out the adapter. This forces the collet/adapter taper to position the collet rather than the back of the adapter thus enhancing TIR by allowing the threaded end of the collet to "float" somewhat (at least as much as the ID of the back of the adapter will allow). The excess length was removed after the wheel was put on and loctited in position for pinning, and pinned.

Along those lines, the 1.238x20 ID thread was cut loose (< class 1) so that it would not impose any force on the collet radially due to draw tube misalignment, to allow the collet thread to start and turn easily, and to accomodate Hardinge collets from work as well as my Chinese collets at home (which have an undersized OD thread).

Measuring with a ruler shows a length of about 14 3/4"-ish from the end of the draw tube at the handwheel to 0.500 inside the grabber where the tube ends. Most dimensions on this thing are in the "that looks about right" category.

BTW, you can buy a MT5 to 5C adapter from Grizzly as a service part for their collet closer. My initial plan was to do this to save the effort turning precise tapers. When my adapter showed up, it was unusable. The collet pin protruded from the side of the MT5 taper which could have at least caused serious runout and potentially damaged my lathe. I corrected this by machining it flush. However, the ID was nowhere near concentric to the OD and I was seeing almost 0.005 TIR between OD and ID. So, I just made one although the Grizzly adapater was correctable with a similar amount of effort. The 10 deg, 5C taper was cut with the adapter installed and matchmarked into my lathe spindle. Thus, any runout in my spindle and the male/female MT5 would be compensated for. Removal and reinstallation get's me typically to 0.0000 to 0.0002 TIR and is very sensitive to the least amount of dirt or oil on the tapers.

Now, all I have to do is to make an adapter extracting tool to be able to safely remove the adapter from the spindle. Right now, I tap it out with a long piece of copper tubing. This is risky because it usually means the adapter comes shooting out of the lathe which could damage paint, bed ways, the adapter, etc. I can't tap on the pipe and be at the headstock side at the same time to grab the adapter as it comes out. Right now, my wife grabs it as it comes out. I'm thinking some kind of pickle fork to get between the adapter flange and the spindle made from a non-marring material like brass.

John

 

[Pauls77]

author=jgedde link=topic=3630.msg26501#msg26501 date=1316458675
I can't tap on the pipe and be at the headstock side at the same time to grab the adapter as it comes out. Right now, my wife grabs it as it comes out. I'm thinking some kind of pickle fork to get between the adapter flange and the spindle made from a non-marring material like brass.

That's what tailstocks are for ;-)

PaulS

 

[jgedde]

OK. Here are the final photos of it installed. I borrowed a precision Hardinge collet from work (upgraded precision type sold with an HLV).

Also here is a video showing the measured runout using an end mill in the Hardinge collet (0.0002 to 0.0003")

John

http://youtu.be/1XbZ2eoMu20

 

[jgedde]

author=Pauls77 link=topic=3630.msg26510#msg26510 date=1316466558

author=jgedde link=topic=3630.msg26501#msg26501 date=1316458675
I can't tap on the pipe and be at the headstock side at the same time to grab the adapter as it comes out. Right now, my wife grabs it as it comes out. I'm thinking some kind of pickle fork to get between the adapter flange and the spindle made from a non-marring material like brass.

That's what tailstocks are for ;-)

PaulS

Yeah, I reckon... ;0

John