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ER40 collet chuck

Brian H

Brian H

Super User
I know these are readily available for purchase, but I just wanted to see if I could do it. The first challenge was getting the D1-4 pins and lock screws right. Now for the taper of the collet. Before I tackle the threading I'll practice on some scrap pieces.
I put a witness mark on the chuck and spindle so theoretically it will stay concentric.
 

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I have a question for anyone that has tried to turn a 1.5mm metric thread on an imperial lathe...
I have all the change gears in place and the do-dads set to the recommended spots.
my first attempt I got a 1.46 mm and I moved the lever one spot over and got a 1.52mm.

Since this is a collet chuck and the nut is already turned to 1.5mm, and I only have one shot at this, ( I wish I had a 50mm piece of scrap to try/test fit), any suggestions on which would be the best choice for a nice fit...

I will be disappointed to get this far and not be able to thread the piece.
 
In order to get metric on imperial you have to have the 127T gear in the chain in order to create the 2.54 ratio. Or CNC or Electronic Lead Screw.
 
Not quite sure what you mean 'moved the lever over one spot'. There is 'a' specific gear + lever selection that results in the target pitch. Here is mine for example but you would have to confirm your own lathe. I haven't looked at this is a while, hopefully correct, but I think it saying I can cut 1.5mm pitch with multiple different gear arrangements, but each has its own unique (different) lever assignment. If I move the lever to left or right, it results in a different pitch. BTW this particular pitch turns out to be 1.500000 exactly based on collective gear ratios. Now I have heard of lathes that appear as though they can cut a certain size, but they are actually playing roundoff games on the chart. Instead of 0.4 (exactly) it works out to 0.36295 (just making up numbers but hopefully makes sense).

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Janger said:
Somebody, or I read it?, told me you can't use the thread dial and have to keep the carriage engaged at all times. on metric threads with an imperial lead screw. Is that true?
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yes, however, I watched an interesting video on "ox-tools" YouTube channel last night that has a cool workaround for that. If I knew how to link things I would do that...
 
PeterT said:
Not quite sure what you mean 'moved the lever over one spot'. There is 'a' specific gear + lever selection that results in the target pitch. Here is mine for example but you would have to confirm your own lathe. I haven't looked at this is a while, hopefully correct, but I think it saying I can cut 1.5mm pitch with multiple different gear arrangements, but each has its own unique (different) lever assignment. If I move the lever to left or right, it results in a different pitch. BTW this particular pitch turns out to be 1.500000 exactly based on collective gear ratios. Now I have heard of lathes that appear as though they can cut a certain size, but they are actually playing roundoff games on the chart. Instead of 0.4 (exactly) it works out to 0.36295 (just making up numbers but hopefully makes sense).

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Thanks Peter, I will take a picture of the chart on my lathe (King 1236). I know it's not a 127 tooth gear. Hopefully I can clarify with the picture
 
Brian H said:
yes, however, I watched an interesting video on "ox-tools" YouTube channel last night that has a cool workaround for that. If I knew how to link things I would do that...
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just copy the URL of the video and paste it into your reply. like this:

 
Brian H said:
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Sorry this is a bit scattered. I can only post pictures with my phone and its a paint to type with it.

As per the manual, the center gear hub stays in place. outer gear is 91T inner gear is 86T
top gear is a 45T and lower a 60T (its actually stamped 1.5mm)

I placed the gear box levers in "B-6" as per the chart and turned a 1.46mm thread. Just for curiosity sake I switched to "B-5" and turned a 1.52mm thread.

I couldn't get an accurate measurment with calipers so I used a dial indicator and turned the chuck 1 revolution. I couldn't figure why the thread pitch guage didn't quite fit...

I hope this clarifies things a bit
 
I think you have a single 1.5mm pitch setting using this specific gear & lever arrangement (B-6 combination). So if you did all that right & the physical pitch is different, we need to dig deeper. It would be a bit better to make higher number of turns, say 5 turns & divide the (accurately measured) traverse by 5. As mentioned. don't disengage the half nuts.
 

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Brian H said:
60T (its actually stamped 1.5mm)
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The 1.5 is likely the gear pitch & 60 is tooth count usually designated 'Z'.

Do you engage the leadscrew with clam shells or equivalent? Maybe splitting hairs but ensure the engagement is nice & positive, nestled within the threads. This may require a just bit of headstock rotation just to to get it there because you likely wont be referencing off of thread indicating marks. But once in, start rotating the chuck in one direction only (to eliminate any backlash effects). Make a witness mark spindle vs stationary point on headstock. Rotate more times like 5 as I mentioned in one direction only. Don't overshoot & don't back up Use a dial indicator on a mag stand or something reliable (not calipers) to measure carriage displacement. Divide displacement by 5. See if that improves the pitch towards 1.50mm
 
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