Blind Bearing Pullers: interchanging collets (SO CG41-13 (3/8") & OTC 33857)

[asavage]

My situation is that I own most of a SO CG40CB Blind Hole Bearing Puller set. I say "most", because the 3/8-7/16" collet, CG41-13, is missing, and is made of unobtainium (or close to it).

SO's catalog lists the expanding rod's external thread (the part that threads into its matching collets) as 3/8-24:



The corresponding 3/8" collet for the OTC 981 set is 33857, and its expanding rod ("Actuator Pin") is 28250. I've been unable to locate the external thread spec on either of these OTC parts.



I've ordered the OTC collet, but not the Actuator Rod just yet; I am kind of hoping that the SO rod will work with the OTC collet, but that's perhaps asking for too much tool design cloning.

Does anybody know (or have one to measure) the thread size of the smallest OTC Actuator Pin? In the OTC set, it's only used for the 5/16" & 3/8" collets.

 

[asavage]

[Two weeks later]
The OTC 3/8" collet has a range to 3/8".
As shown, the OTC collet and Actuator Rod are both a bit longer than the SO parts (though with the same 3/8"-24 thread):



So, while the SO Actuator rod will thread into the OTC 3/8" collet, it won't push the ball inside and therefore won't work.

Additionally, while the SO collets are listed with operating ranges (3/8"-7/16"), the OTC collets are not; the OTC 3/8" collet is actually 5/16"-3/8", so . . . I ordered the incorrect OTC collet for my application anyway. I need the OTC 33858 3/8"-7/16" collet, and that in turn uses yet a different Actuator Rod, 3/16", 28253 .

 

[asavage]

With the OTC 28250 1/8" Actuator Rod fully inserted into the OTC 33857 3/8" Collet, the collet's thin flanges are only .015" larger dia. than 3/8" -- in the pic below, the Actuator Rod is screwed in as far as it will go, and you can just make out the ball bearing fully extended within the collet) . . .




. . . and not anywhere in the ballpark of > 7/16" that the OTC packaging states:



I've submitted an RMA request for these, they're going back to Bosch (OTC).

 

[oldmachinenut]

I’ve run into this problem in the past, one of my students for some reason ground the end of the rod. I just added balls to the collet to get the rod to reach.

 

[asavage]

The new Actuator Rod is fully inserted in the previous pic (but not in the pic below), as far as it will go, and the ball is within 3/16" of coming out the end! It is doubtful that pushing the ball further toward the end will obtain > 7/16" flanges diameter, which is what would be needed to keep the flanges behind a 7/16" bushing.

 

[W-Cummins]

For a while the snap-on parts were not available, they are now back in production. Apparently the company that was making them went out of business, and I was told that snap-on either bought them out or picked up the manufacturering of the parts...

 

[oldmachinenut]

The new Actuator Rod is fully inserted in the previous pic (but not in the pic below), as far as it will go, and the ball is within 3/16" of coming out the end! It is doubtful that pushing the ball further toward the end will obtain > 7/16" flanges diameter, which is what would be needed to keep the flanges behind a 7/16" bushing.

I have had the ball all the way to being flush with the end, the collet will spring back.

 

[asavage]

Not this one; the ball cannot travel further without severe force.

 

[oldmachinenut]

Not this one; the ball cannot travel further without severe force.

It will go farther, I’ve done it many times using them for over 40 years.

 

[asavage]

With a modified rod?
This one is going back. For the price I paid for it, I expect it to work to spec out-of-the-box. If it was HF ****, I'd cut off a drill bit shank, stuff it behind the rod, and go to town, but not for the OTC/Bosch $$$ I paid for this.

 

[asavage]

It will go farther, I’ve done it many times using them for over 40 years.

OK, I was wrong. Thanks for that tip. Yes, the actuator rod will travel further, though if looking at the hex end, it looks as if it's run out of travel).

 

[oldmachinenut]

OK, I was wrong. Thanks for that tip. Yes, the actuator rod will travel further, though if looking at the hex end, it looks as if it's run out of travel).

It’s all good, I hope I helped.