Holding a barrel in a 4 jaw

[tobnpr]

He uses split steel rings while I use aluminum ones.

I like it... I'm sure less movement than with spider screws. Is there a small flat on the inside bearing surface, or is it a full radius? Radius would allow better freedom of movement- but damned if I can figger out how I'd machine it.

I have since upgraded the bolts to 12 points. Much easier to adjust than Allen head ones.

Great idea. Thanks for sharing it.

 

[Bamban]

I like it... I'm sure less movement than with spider screws. Is there a small flat on the inside bearing surface, or is it a full radius? Radius would allow better freedom of movement- but damned if I can figger out how I'd machine it.

Great idea. Thanks for sharing it.

Thank you for the kind words.

I bought the aluminum unthreaded spacers from McM- Carr. 1 inch ID, I just machined the ID for specific application.



I did not want to deal with 2 inch OD so I threaded an aluminum piece, slid the spacers and locked them down with the 1 inch nut. Picture shows my spares not turned down. Note the nut itself was turned down somewhat from the previous batch I made.



There is a small flat in the ID, as you can see the chamfered side in the picture in the previous post. The 1/4 inch thick piece is strong enough to clamp at the edge of the chuck (used the 6J) then cut the chamfer from inside out after turning the ID to the specific application.

The 12 points are pretty handy, I just happen to have some leftover ARP bolts from my car racing days.

On a related subject, when I took the TRUMP 1236 apart I replaced the headstock hold down bolts with ARP bolts from Summit. Made life much easier when aligning/torquing (big PITA) the headstock down.

 

[LVLAaron]

I like it... I'm sure less movement than with spider screws. Is there a small flat on the inside bearing surface, or is it a full radius? Radius would allow better freedom of movement- but damned if I can figger out how I'd machine it.

Great idea. Thanks for sharing it.

Grind a tool! Need a tool make a tool

 

[Alex Wheeler]

Just keep checking your work. I did the full radius ring at one point. If it works for you that's all that matters.

 

[Bamban]

Just keep checking your work. I did the full radius ring at one point. If it works for you that's all that matters.

Thank you for the reminder, Alex.

I do check workholding integrity multiple times.

 

[Bogusname]

Don’t laugh. It’s simple.

 

[Dusty Stevens]

Don’t laugh. It’s simple.

I like it

 

[SKWERLZ]

Don’t laugh. It’s simple.

Brilliant!

 

[Will Henry]

Don’t laugh. It’s simple.

Laugh? Only out of happiness that someone embraces simplicity and functionality over all else; as do I. WH

 

[skeetlee]

 

[skeetlee]

The chuck above is one I made after talking with Alex Wheeler. Best tool in my shop too. Rock solid. I hold my ball bearing to the studs with a magnet I matched the center of the stud for. I’ll never chamber another barrel without it!!

 

[Dusty Stevens]

The chuck above is one I made after talking with Alex Wheeler. Best tool in my shop too. Rock solid. I hold my ball bearing to the studs with a magnet I matched the center of the stud for. I’ll never chamber another barrel without it!!

You need me to send you a chunk of brass for that odd pad you got?

 

[BuffaloBill]

The chuck above is one I made after talking with Alex Wheeler. Best tool in my shop too. Rock solid. I hold my ball bearing to the studs with a magnet I matched the center of the stud for. I’ll never chamber another barrel without it!!

I like the magnet idea you speak of. I’d been using gravity (placing all the blocks/bearing balls in the 12 O’Clock position). But magnetism would sure be handy. I wonder if magnetizing the set screws would last for a useful time?

I made this one with only 4 of the usual 6 D1-6 mounting pins. I made it from one piece, in an attempt to minimize thickness. It seems very solid. I used 1/2-20 screws but for dialing in the last couple tenths would be nice to have even finer thread pitch. I’ve only done this a few times and imagine that process takes less time for you folks with more experience!

 

[skeetlee]

You need me to send you a chunk of brass for that odd pad you got?

i could use a piece. i have several of all different sizes they always end up in the chip pan when i go to remove a barrel and some even get pitched when i clean out the chip tray!

 

[Alex Wheeler]

I will add that an independent chuck with sacrificial metal will move. A set true type chuck will apply even pressure on each jaw. Independently adjustable jaw chucks can and will end up with more pressure on one jaw than another. Under load, expect movement. If using independently adjustable jaws, use steel parts. If using sacrificial metals like copper wire use scroll chucks.

 

[INTJ]

After I had chambered my first couple of barrels a few years ago I started thinking about finding a better way but never really made a decision. Lately, I find that a plain old four jaw chuck, home made spider, and aluminum shims are so fast, accurate, and easy that I now wonder if a fancier chuck is worth it.

 

[skeeljc]

How many teeth should an aluminum pad cover?

 

[jdh47]

Sure a four jaw or cat head might not exert the same force on each jaw but as long as the barrel is indicated in well it really doesn’t matter. Straight is straight. We don’t take heavy cuts turning a tenon and threading. As long as the barrel is held straight without bending results will be good.
If anyone is worried about exerting too much force on one jaw or another then use a torque wrench to tighten when indicating.

 

[tobnpr]

How many teeth should an aluminum pad cover?

If you're using a outboard spider, a setup using flat pads like that will not allow the barrel to gimbal freely- you'd be bending it.

 

[skeeljc]

If you're using a outboard spider, a setup using flat pads like that will not allow the barrel to gimbal freely- you'd be bending it.

I cut the pads back so they cover only the first tooth. I am trying to do what Gordy Gritters does in his video. I will be using an outboard spider.