5c collet chuck

[kd0afk]

Tomorrow's the big day. Paint will be set and I can start machining. I was able to rig a skyhook style mount for my phone so I can film it after all.

 

[Philjoe5]

I'm looking forward to your progress

Phil

 

[mc_n_g]

Built one about 2.5 years ago. It was a nice project to work on.
I would recommend some cheap C2 brazed carbide inserts to get through the bulk of the junk material.
I cut the taper for the collet using a carbide insert tool and using marking fluid on one of the collets. I did not grind it.
The cast iron will chew up HSS if you try to use it on the skin.
Use the C2 until you get to a finishing cut. You can even use the C2 on a finishing cut if you form a larger radius on it.
I found the quality of the iron to be very good and no inclusions.
Trepanning the deep pocket will be one of your challenges. It will squeal and chatter. Have a good hook on the tool end and resharpen it as you go.
Have a large diameter boring bar to minimize deflection when boring the 5C hole.
Use a vacuum or a mask because the iron dust is going to go everywhere!
Take your time and plan out the measurements and know exactly how much you need to cut.
Final finish I went with various grades of silicon carbide sandpaper (OMG panic he used sandpaper) and then used fine grade emery paper for a polish.
I finally used a clear spray coat over the top.
For me it was not about the 'beautification' but having a usable repeatable tool.
The 5C chuck gets used and swapped regularly
I get between 0 and 0.0004" when I take it on and off. This may not be acceptable to you but is works for me.
Around 6" mark I get 0.001" - 0.004" depending upon the collet. I bought some cheap collets and do not expect a whole lot better.
One last hint. Drill the tommy bar holes before you reach the final diameter. After drilling them drive wooden dowels in the holes so you do not get the 'chatter' impact from going over a hole. Also do the sanding with the dowels in the holes as it leaves a nice edge to the tommy holes. Remove the wood dowel rods with a screw to pull it out.

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[kd0afk]

Thank you for the first hand input on this. I'm to the trepanning stage now. I used a 1/2" bit for maximum rigidity and spent the better part of the afternoon grinding it to shape. I'll finish it up today and have at it.
The one problem I ran into is getting it centered. I opted for the best visual registration ad I could but it still looks like it wobbles a bit. Oh well, it's my first and ad long as it's accurate, that's all that matters to me.

 

[kd0afk]

One thing, when I grind the rake into the trepanning tool, I want it to run nose to tail and not side to side right, like a parting tool?

 

[kd0afk]

I just came from the shop and I think I'll leave the trepanning for the big dogs. I'll say when I've been licked and I think I'll go with the alternate ball race assembly. It calls for boring to the full depth the counterboring that to accommodate a boss that screws in. It duplicates the trepan and will work.

 

[Swifty]

I just want to point out that when checking the taper with a collet, the collet will be sprung open, making it a slightly different taper.
If you have a solid 5C shank it would be ideal to use for checking the taper.

Paul.

 

[kd0afk]

I just want to point out that when checking the taper with a collet, the collet will be sprung open, making it a slightly different taper.
If you have a solid 5C shank it would be ideal to use for checking the taper.

Paul.

Everything if seen and read about cutting a collet taper says that you need to insert a piece of stock that just fits the collet i.e. If it's a 1" collet you use a 1" piece of stock to keep the collet expanded to its full size. You are suggesting the exact opposite.

 

[mc_n_g]

I had a 3/8" collet with a 3/8" drill rod in it so I could handle it. It also allows you to put pressure on the collet and see how the taper matched up when marked.
Forgot to mention you should make a plug that very closely matches the threads on your spindle for testing the back mounting plate. This way you do not have to keep removing the chuck and possibly screw up your threading operation. You would like to have the back plate with a flat surface so that it registers to you spindle at the same spot all the time. I don't know what lathe you are making this on/for but make sure you have a good registration surface on the outside of your spindle.
Do not finish the outer cuts until you join the back plate with the front part. This will assure you a smooth surface between the two.
Take extra care and measurements to make sure the lip of the back plate and the hole of the front portion are a very close fit. You do this to make sure your front part will not wiggle out of registration between the two surfaces and if you ever need to take it apart (heaven forbid) it will not have play.
Not cutting the trepanned slot will give you plenty of time to cut extra iron! I only slightly remember the option about cutting it all out and plugging. Use good 1/4 or 5/16 screws at a minimum if there is room.

 

[kd0afk]

I have both a 3 & 4 jaw chucks. If I make my spindle test plug and test it against the chuck I'm not using it should be ok right? I'm thinking there might be slight variations between the two chucks but I'm also thinking that it should be okay to use one as a tester.

 

[kd0afk]

Mc n g, to make the test plug, did you actually thread the plug or just make it for the spindle register? It would make sense to make two, one a go/no-go plug for the register and a finished threaded plug for the perfect fit. Would be a handy set to have.

 

[mc_n_g]

No I made the threaded plug to test the threads on the back plate so it does not have to be removed.
You need the surface of the back place to be machined(lathed) and slightly proud (as per drawing) so it interacts with the register on your spindle.
You want the back plate to touch the register/shoulder of the spindle so it comes to a solid stopping point.
This way all cuts are referenced to the same place and orientation in relation to the spindle.

 

[Swifty]

Everything if seen and read about cutting a collet taper says that you need to insert a piece of stock that just fits the collet i.e. If it's a 1" collet you use a 1" piece of stock to keep the collet expanded to its full size. You are suggesting the exact opposite.

All my 5C collets are sprung slightly open, the idea of putting a piece of material the exact collet size is a good one, but the problem is how do you close the collet down on the material.

Paul.

 

[kd0afk]

I'll have to double check but when I put a rod the size that's marked on the collet it's almost a press fit. I guess I don't have that problem.

 

[kd0afk]

I made my threaded plug. She turned out perfect, no play at all with both of my chucks.
I got the back side of the faceplate faced, the through hole bored at 1.375" and the shoulder bored to 1.510" the exact OD of my spindle. I just got done grinding the threading tool and I'll tackle the threads tomorrow, its late and I'm tired.

 

[kd0afk]

I thought I'd get back out tonight and finish up the baseplate. We'll, my fear happened. I screwed up the threading. The bit I ground was wrong, not deep enough and it scraped the hole bigger. I didn't catch it till it was too late.
I emailed MLA, hopefully he can sell me a replacement.
Live and learn I guess. I'm just wondering if it can be saved maybe?
Life sux right now.

 

[Swifty]

Bummer, any chance of putting in some type of insert?

Paul.

 

[kd0afk]

Would tig welding to add material to the hole be a suitable fix for my rookie mistake or should I just start with a new backplate?

 

[kd0afk]

Bummer, any chance of putting in some type of insert?

Paul.

I have the steel to do that. Probably thread it and use permanent locktite right?
I'm just sick about this.

 

[kd0afk]

Another option if Andrew won't sell me the part I can always just buy a backplate from shars. I think they're around $20 or so.
Heck Cattail foundry can cast me one for less than $30