Er 40 chuck

Is there no way to just thread to a small od and matting id thread? I assume we are talking the for the collet nut
 
well mistakes happen ... live and learn .

i could turn it down a little and make it a non standard size i think ... but i did want to make it to fit a standard collet nut .

i have enough left of the origonal stock to try again , but there wont be enough to make a nut as well .. im going to have to ponder this for a bit an make up my mind what direction to go .
most likely ill just turn it down a smidge and use a standard thread if there is enough material to work with
 
bosephus said:
.. im going to have to ponder this for a bit an make up my mind what direction to go ...
Click to expand...

I think you can save it. Please bear in mind that I'm thinking 'Atlas' here, and the ease of setting up change gears, and especially the ease of engaging/disengaging the spindle gear.

I'm thinking that: If you haven't disturbed the threading/change gears, and the toolpost positioning, that all the possible combinations of thread re-engagement matching is the same as the tooth count of the spindle gear, no matter how the leadscrew is engaged.

If you were to:
Back-out the cross-slide a little, enuff to just clear the threads.
Move the carriage to the threaded area.
Re-engage the leadscrew.
Disengage the spindle gear from the changegear.
Slowly turn the chuck 'till the workpiece thread aligns with the cutting tool.
Re-engage the spindle gear.
Rotate the chuck by hand to remove all slack in the system.
Advance the crossfeed to check tool fit in the old threads.
Closely examine the tool/thread alignment.
Disengage the spindle gear, rotate chuck one tooth at-a-time, re-engage spindle gear.
Re-examine, re-index by one tooth until aligned.

Since the tool must move by one thread spacing for each rotation of the chuck, the total combination of possible tool positions is limited by the spindle gear tooth count.

Of course, this assumes that the only change to the setup was inadvertently disengaging the leadscrew.

Please tell me this is wrong...
 
sg51buss

i dont think you are wrong ... matter of fact that is pretty nearly exactly what i did to get the tool back into proper position .
the second mistake came when i did not stop take a deep breath and go back into the house and get my reading spectacles ... what i thought was lined up properly with the threads was just a smidge out .
and thinking i had it right ... i made what should have been a repeat of my last cut , and wound up with two sets of threads .

lesson learned .. and excepting a few hours of work a cheap lesson at that ... the 4140 only cost $18 or so shipped i think .
and i have enough left to make another attempt .

i did do some figuring , if i clean up what i have threaded things will be getting a bit thin for my tastes for er40 collets at least.
but ... i have two options ...
1, i can either salvage enough material out of it to make my nut with , and restart with my left over chunk

or 2, i can oil it up set it aside and save it in case i ever run into a need to adapt something else to my spindle . and just buy a collet nut .

im leaning towards the second option ... just so i can salvage a few hours of my work
 
Wiil if it's any help I save everything. If it's bigger then 1x1x.25, I have to keep that just incase ahaha. If it was me and I had enough to redo it, and was not comfy with trying to salvage what I had, I would just start over.
 
bosephus said:
... i did not stop take a deep breath and go back into the house and get my reading spectacles ... .
Click to expand...

Oh no! Yeah, been there, done that. I now keep an Optivisor near the machine, wear it all the time, as in my avatar. Can't do anything without it now...

bosephus said:
... two options ...
2, i can oil it up set it aside and save it in case i ever run into a need to adapt something else to my spindle ...
Click to expand...

I like option 2. I also have a couple of 'spindle ready' blanks for future projects. If you think about it, it may have been best if the tommybar holes were drilled prior to the collet thread attempt, as torque fitting of the fixture to the spindle would give better repeatable accuracy.

Speaking of which, taking a step back, did you run a DTI against the mount registration face of your spindle?

Long ago, I found a tiny 0.0002" runout on mine. Did a cleanup skim on it, so that all future spindle attachments would run square, and future face cleanups on those attachments would keep things running true...
 
i think i am going with option two , im sure that in the future i will need to adapt something else to my spindle .

chuckorlando
im the same way , i throw out nothing that may be useful , ive been know to tear apart broken stuff to save nuts and bolts and other useful stuff .

sg51buss

tommy bar holes , i was going to drill them before attempting the threads for the nut , but i decided to cheat i did drill and tap the holes for the retainers so i used a longer bolt in those holes to tighten the chuck up on my spindle as i wasnt 100% sure of where i wanted to put the tommy bar holes , now i am glad i waited .
i did set an indicater against the registration face , luckily i couldnt measure any run out at all ., i must have done something right in my set up as when i did spin it on my spindle i didnt get any run out on the other end either .... even a blind squirrel gets a nut every now and then .

i think today is going to be a clean up day , and tomorrow i will take a deep breath and start over with my left over piece .
 
One last comment (for now, anyway). While researching the ER specs, I came across the recommended torque specs for the collet nut, as required to get the tool grip strength, and more importantly, the advertised collet accuracy.

Anywhere from 200 to 300 ft-lbs!!!

Holy elbow pop! I have absolutely no intention to go that tight! I just want the collet for workholding, and would like to stay below 10 ft-lbs.

That's why I'm currently fussing over my collet setup, and regrinding my collets. To try to get the accuracy without all that torque...
 
i had those same concerns .. until i learned that those very high torque specs are for for hardened ground and polished materials .
from what i have learned .. most all materials us hobbiests will be using anywhere from 20-50 ft lbs will be way more then enough torgue to secure our work
 
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