Issues with holding end mills in Beall collet chuck on a Sherline mill

[Aaron_W]

Here is a photo of the seating end of the Beall chuck that I purchased for my Sherline lathe, in January 2020. I don't remember specifying that it was for Sherline, when I placed the order. The item on the invoice states, "LA CHUCK 3416". The description on the invoice states, "3/4-16 CHUCK BODY, NUT & SPANNER".
View attachment 373988
I hope someone lets me know if this chuck is the wrong version for Sherline.

I would like to see a photo of the Taig version of the chuck.

Karl

It appears they no longer offer two versions of the 3/4-16 collet chuck. When I bought mine around 2016 it was mentioned in the 3/4-16 description that you should let them know of it was for a Sherline or Taig lathe / mill. I see they no longer offer this advice, it is possible the reason for mentioning which was more for the Taig side of the option.

Taig has a longer spindle thread than Sherline, so when people use Sherline accessories on a Taig they have to use a spacer so that it registers correctly (without the spacer the thread will bottom out before reaching the register). This is not needed when using Taig accessories on a Sherline, and to my knowledge there is no issue using a Taig accessory on a Sherline spindle. I'm guessing Beall stopped offering Sherline / Taig specific chucks and just make all with the deeper threading to simplify logistics.

I have a Taig ER-16 collet chuck and have not had any issue using it with my Sherline lathe. I have only used the ER-16 for work holding though which is significantly less sensitive than holding an end mill.

 

[Karl A]

It appears they no longer offer two versions of the 3/4-16 collet chuck. ...

Taig has a longer spindle thread than Sherline, so when people use Sherline accessories on a Taig they have to use a spacer so that it registers correctly (without the spacer the thread will bottom out before reaching the register). This is not needed when using Taig accessories on a Sherline, and to my knowledge there is no issue using a Taig accessory on a Sherline spindle. I'm guessing Beall stopped offering Sherline / Taig specific chucks and just make all with the deeper threading to simplify logistics.
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Beall now making one version of the chuck for both Taig and Sherline explains the deep threads on my chuck.

Thank you for the explanation. For me, it closes one technical issue.

 

[Karl A]

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Everyone here has spoken very highly of the Beall collet chuck, and I haven't been able to find any reports of issues like mine, so I assume I'm doing something wrong (or have damaged the chuck somehow).
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I bought my Beall collet chuck for work-holding on my Sherline lathe. I measured 0.0008-inch TIR in the ID of the mouth with the nut removed. This amount of runout was more than I expected or wanted. Using a ring shim, I have verified that the run out is due to the chuck, not the lathe spindle face. (Adding a ring shim caused the chuck to screw onto the spindle 1/4-turn less, but the point of maximum runout in the chuck did not shift. If the runout had been due to the lathe spindle face, the point of maximum run out in the chuck would have shifted.)

Karl

 

[brino]

Adding a ring shim caused the chuck to screw onto the spindle 1/4-turn less, but the point of maximum runout in the chuck did not shift. If the runout had been due to the lathe spindle face, the point of maximum run out in the chuck would have shifted.

Great deducing and debug skills!

I will have to remember that trick.

-brino

 

[Karl A]

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I bought a Beall ER32 collet chuck when I got the mill based on all the recommendations I've seen, and have essentially always used it. Well, about a week ago, I used a Sherline end mill holder instead of the Beall collet chuck since I had a cramped setup and the chuck would have run in to a clamp. I was shocked at how much smoother things ran with the end mill holder. I could take cuts there were simultaneously far deeper, with greater stepover, and faster feed than with the collet chuck. I've been using it with the end mill holder ever since, and its night and day. The mill finally feels exactly as I assumed it should.
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I recently purchased a 3/8" end-mill holder from Sherline, for a reality check. I had been using a Beall ER32 collet chuck for holding 3/8" end-mills. Milling with it has not been smooth, and the runout I measured in year 2020 at the ID of the Beall chuck was significantly greater with the Beall chuck installed on my Sherline mill headstock, compared to the runout I measured with the Beall chuck installed on my Sherline lathe headstock: 1.5 thousandths-of-an-inch TIR on mill headstock, compared to 8 thousandths-of-an-inch TIR on lathe headstock.

I measured the ID runout of the new 3/8" end-mill holder installed on on my lathe headstock and on mill headstocks:
- lathe headstock: 0.7 thousandths-of-an-inch TIR
- mill headstock: 0.4 thousandths-of-an-inch TIR

I then faced the face of the spindle on each headstock, using a knife tool on the lathe. I remeasured the ID runout of the 3/8" end-mill holder:
- lathe headstock after facing: 1.0 thousandths-of-an-inch TIR
- mill headstock after facing: 0.3 thousandths-of-an-inch TIR
I also marked the circumference of the 3/8" end-mill holder at the point of maximum maximum reading on the dial test indicator, during each reading. The marks were not at the same location; the differed by about a quarter of a revolution.

I measured the runout of the spindle faces after facing. The dial test indicator needle did not move when I rotated the spindles. The runout values before facing where 0.2 thousandths-of-an-inch TIR.

My tentative explanation for the difference in runout readings of the 3/8" end-mill holder on the lathe headstock and mill headstock is that the spindle threads differ in how concentric they are.

My tentative conclusion is that if one buys a tool holder or collet chuck that screws onto the spindle of Sherline lathe or mill, one is lucky if one obtains 0-to-0.3 thousandths-of-an-inch TIR. The reliable way to achieve low runout with a tool holder or collet chuck is to make it on a Sherline headstock, and then to only use it on that particular headstock.