Assembling a 3-jaw chuck

V

vavavroom

Joined
Oct 31, 2017
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This chuck is small. Each jaw is about 3/8" long. Very fiddly. I have to insert the springs into the holes in each jaw and cram the assembly inside the chuck case. Even if I use grease to make the springs stick my fingers are too large to hold the three jaws firmly and with precision in place while sliding them into the case. How did they assemble this at the factory?



 
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ripcord said:
Maybe some Scotch tape to hold it together while you insert it?

They probably have some kind of jig to aid in assembly at the factory.
Click to expand...
You have to align the three jaws and compress the springs without any of the jaws twisting or slipping. Yes, I guess they use a jig. If I had a few extra hands I could possibly use tape. The thing is, I have assembled this in the past. No idea how I did it. Cognitive dissonance?
 
I got it back together because I suddenly remembered how I had done it before. I glued 1 jaw with C/A glue to a cutting mat. I inserted the spring with tweezers into the hole of jaw 1. I took jaw 2 and inserted the other end of the spring into jaw 2. I positioned jaw 2 and glued it to the cutting mat. I took jaw three and placed the third spring in place and also the other end of the first spring. Then I glued jaw 3 into place. I could slip the chuck casing over the three jaws. The jaws slid into place with the springs getting compressed. I twisted the case until the jaws were released from the cutting mat. I am now soaking the chuck in acetone to remove the residual C/A glue.

I was more interested in getting this thing back together than in taking decent pictures. Here are crappy photos! I was fidgeting with these parts like a crack addict with Parkinson's.

Step 1


Step 2 and 3


Back in!
 
Last edited:
vavavroom said:
This chuck is small. Each jaw is about 3/8" long. Very fiddly. I have to insert the springs into the holes in each jaw and cram the assembly inside the chuck case. Even if I use grease to make the springs stick my fingers are too large to hold the three jaws firmly and with precision in place while sliding them into the case. How did they assemble this at the factory?



Click to expand...

Most likely a funnel: fit them with no tension in a funnel, push through all at once
 
vavavroom said:
I got it back together because I suddenly remembered how I had done it before. I glued 1 jaw with C/A glue to a cutting mat. I inserted the spring with tweezers into the hole of jaw 1. I took jaw 2 and inserted the other end of the spring into jaw 2. I positioned jaw 2 and glued it to the cutting mat. I took jaw three and placed the third spring in place and also the other end of the first spring. Then I glued jaw 3 into place. I could slip the chuck casing over the three jaws. The jaws slid into place with the springs getting compressed. I twisted the case until the jaws were released from the cutting mat. I am now soaking the chuck in acetone to remove the residual C/A glue.

I was more interested in getting this thing back together than in taking decent pictures. Here are crappy photos! I was fidgeting with these parts like a crack addict with Parkinson's.

Step 1


Step 2 and 3


Back in!
Click to expand...
Is this the one that fits dremel?
 
Jetronic said:
Most likely a funnel: fit them with no tension in a funnel, push through all at once
Click to expand...
The chuck casing is already like a funnel. You need to get the jaws in pointy ends first while also having the three springs in place. Because of the length of the casing, the three jaws drop all the way down if the springs are not in place and close the gap between the jaws. The springs have to be placed before the whole assembly is slid into the casing while alignment of the jaws is maintained. The
Maybe a magnet could be used to hold the three jaws in place. That's the same concept as gluing the jaws to a base. Then I'd have to demagnetize the chuck after assembly which is of course no problem. I have a demagnetizer. I didn't try a magnet because I didn't have a suitable one lying around.

If you have somehow managed to get the three jaws with the springs in between them into a funnel, how do you push the three jaws into the casing? You can only push from the narrow end of the funnel and the jaws need to go into the casing pointy ends first.
 
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vavavroom said:
I want to see that.

Like this? Only two more jaws and one spring to go! Am I allowed to use the dark arts?
Click to expand...

So make a loop with the zip tie and assemble the parts like you did in step 2 above. Tighten the zip tie until the assembly will fit in the case. Slide the parts into the case through the zip tie.

Just my $0.02
 
tnt_motorsports said:
So make a loop with the zip tie and assemble the parts like you did in step 2 above. Tighten the zip tie until the assembly will fit in the case. Slide the parts into the case through the zip tie.

Just my $0.02
Click to expand...
Let's get started with this.

You see, not only makes the zip tie for an out-of-round retainer but the three jaws don't stay in alignment to each other but each will rotate unless you fix their bases to the surface they sit on.




Here is the magnet method that wors very well. But you have to demagnetize the chuck afterward.

 
I see only four methods:
1. glue the jaws
2. stick the jaws onto a surface that has pressure-sensitive adhesive on it
3. stick the jaws on a magnetic surface
4. Make a jig

Jig Proof of Concept:

I made a small ball from modeling clay and flattened it. I pressed the jaws into the clay so the spring holes were level with the clay.


I removed the jaws and was left with three impressions


Encouraged by this, I made another ball of clay but I added metal powder to make the baked clay more durable. The springs can be rolled into position and need only a nudge to slide into position. Once the springs are in place, I slip the casing over the assembly, then turn the whole thing over including the jig, and wiggle the jig loose. All that's left to do is to place a washer and screw the casing back on.


If you wonder why I need to take the chunks apart in the first place, look at the worn edges that grab the rotary bit. I like to get a bit more life out of them by restoring a sharp edge.
 
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slo town said:
Foul language using a dozen single-syllable curse words, all merged together into one gigantic multi-syllable curse word is a sign of immense frustration - and linguistic brilliance. Sometimes it becomes something akin to poetry.

Scott
Click to expand...
My vocabulary includes sesquipedalian wordsmithery that will not only confuse @Jdeere562 but also make him blush with delight. Others may say Hail Marys and cross themselves while hiding their children and pets when they hear me.
 
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vavavroom said:
My vocabulary includes sesquipedalian concoctions that will not only confuse @Jdeere562 but also make him blush with delight.
Click to expand...
My word salad would be comprised with words starting with the letters......I better not go there. But there have been times when I've been working in the garage and speaking loudly enough that Sue comes out and says, "Stop that. People are going to think you're talking to me!".

Scott
 
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