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No excuse not to make an er32 chuck for the lathe

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mickri

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#1
I am just about finished with the tool holders for my norman style qctp and already realize that I am going to need more tool holders. Can you ever have too many?? I see an add on Craigslist for a company selling some 1018 crs 1 1/4" x 2" flat bar. Stop by and it is a CNC machine shop trying to sell their drops instead of sending them out for scrap value. Owner asked if there is anything else I could use and I mention 2" to 2 1/2" round bar. Takes me over to another rack and there is a 6" long piece of 2" round bar 1018 crs. That will work and he gives it to me no charge. They had a lot of other stuff that I can see would be useful for other projects down the road. And at less than $1 per lb fits nicely in my budget. The shop is in Visalia, CA. 1130 E. Acequia Street.

I now have the material. No excuse not to start making it.
 

hman

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#2
Looks like you found a GREAT source. Congratulations!
 

Tozguy

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#3
So howz it coming mickri? :)
Looking forward to seeing how you go about it.
 

mickri

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#4
Hope to get started the middle of next week. Halligan142 has a nice video on making an er32 chuck for a lathe that I intend to follow. I have watched it so many times that I think I have it down. Have lots of other things that I need to get done too. I am going to finish the first batch of tool holders for my norman style qctp before starting another machining project. I will be using these tool holders to make the er32 chuck.
 

dtsh

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#5
Having done this myself just recently with ER40, I found it quite handy. It's not 100% complete, but it's at a stage where it's usable. I used it today in fact to turn a brass bushing for my Brunton-style pocket transit. The making of the chuck was pretty straightforward. For getting the 8-degree taper just right, I set the compound as close to 8 degrees as I could and once I was close to size I kept checking the fit of a collet and tapping the compound between cuts until the dye on the collet showed full contact.
 

Tozguy

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#6
dish, I did mine that way too. But it left me wondering if the collet taper changes as it tightens and whether we should allow for that.
 

Janderso

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#7
I have a threaded spindle and the ER40 set.
I bought some 4” cast iron, “dura bar” for the mounting plate. The trick is to bore and cut the 1 7/8 8tpi internal thread.
Will be watching your project
 

rgray

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#8
I usually set the compound with a sine bar for things like that.
Can be set off the extended tailstock ram, or better off a ground test bar between centers.
 

mickri

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#9
This is how I intend to make the chuck. First I will figure out how long it needs to be and cut the work piece a little longer. Then I will drill/bore a hole, probably 3/4", all the way through. Next I will bore and thread one end to fit the 1 1/2 x 8 tpi on the spindle. I will then mount my mt2 er32 chuck in the spindle and set the compound to match the taper. Then the work piece gets screwed onto the spindle and I will cut the taper. Last will be cutting the external threads for the collet nut. This is just my general outline of the process. I didn't include every little step.
 

mattthemuppet2

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#10
that place sounds like a great find! Next time you're there, ask if they have some 2" or larger hex bar, then you can make an ER32 collet block. Super handy things. I made an ER25 collet chuck for my Atlas 618 out of hex and I've used the "hex" aspect of it on the mill way more than I expected. Even drilling 2 holes in a rod 180deg from each other is made so much easier with it. Plus I didn't need to mill flats for a spanner :)
 

BaronJ

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#11
dish, I did mine that way too. But it left me wondering if the collet taper changes as it tightens and whether we should allow for that.
No ! The collet taper does not change when tightening, only the bore diameter will alter to grip the workpiece.
 

mickri

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#12
Got started today. I cut the 2" OD round bar to length this morning. That was fun with a hacksaw. Took awhile. This afternoon I was able to face off the rough cut from the hacksaw and got the center hole drilled to my largest drill which is 3/4." Hoping to start Monday boring the center hole to its finished ID of 1" and then bore the headstock end to the minor diameter of the 1 1/2 x 8 tpi. That's the progress so far.
 

mickri

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#14
Looked up the minor diameter. The range is 1.365" to 1.390." Since I tend to be oversize on the holes that I bore I will shoot for the 1.365 which should keep me within the range of minor diameters. In the Halligan142 video he said to make the thread a little sloppy on the fit because the chuck should seat on spindle and not on the threads. Is this correct?
 

BaronJ

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#16
Hi Mick,

Yes that horizontal flat area behind the threads is where you want the best possible fit. The threads only hold the chuck on, its the register that sets the location.
 
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