Author Topic: Holding swamped barrel in vise  (Read 3873 times)

Offline 577SXS

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Holding swamped barrel in vise
« on: October 23, 2020, 12:08:47 AM »
I have been trying to come up with a good way to hold swamped barrels in my milling vise. I've always used shims on either side of small part of barrel to center that part of barrel in vise and haven't been very happy with doing it that way. I just made two aluminum blocks with a pivot point in the center to follow the taper of the barrel. Was simple to make and works great. I used 1"X2" aluminum bar stock and clamped them together in vise then drilled a 1/2" hole between the two blocks. I then made two 1/2" steel pins to put in half holes for the pivot.



Offline Jim Kibler

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Re: Holding swamped barrel in vise
« Reply #1 on: October 23, 2020, 03:00:37 AM »
For manual milling I use a similar aluminum block.  Mine is just shaped on the backside rather than having a pin, though.  I donít understand why you would want to clamp with two of these?  One side should be firmly against the fixed jaw.  Two point contact in clamping isnít too rigid or secure.

Offline Bill Raby

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Re: Holding swamped barrel in vise
« Reply #2 on: October 23, 2020, 06:46:18 AM »
I use a cheap, crummy drill press vise that I got at Menards for about $15. The moveable jaw is very loose and sloppy. It does not stay square to the fixed jaw. In effect it works like what you have in the photo but with one fixed jaw. When tightened down it works good to securely hold a swamped or tapered barrel. I hope this makes sense.

Offline 577SXS

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Re: Holding swamped barrel in vise
« Reply #3 on: October 23, 2020, 02:02:30 PM »
Jim, the reason I clamp with two is I can get bore parallel to vise jaws. If I use one solid jaw of vise the bore will be at an angle. I want my dovetails perpendicular to the bore.

Offline Jim Kibler

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Re: Holding swamped barrel in vise
« Reply #4 on: October 23, 2020, 02:07:47 PM »
I just rotate my vise.  Maybe your vise is fixed?

Offline 577SXS

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Re: Holding swamped barrel in vise
« Reply #5 on: October 23, 2020, 02:35:36 PM »
No I have a pivoting vise I just don't want to have to indicate it back in after I do one dovetail. It really don't matter how you do it as long as its done right.

Offline Jim Kibler

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Re: Holding swamped barrel in vise
« Reply #6 on: October 23, 2020, 06:48:55 PM »
No I have a pivoting vise I just don't want to have to indicate it back in after I do one dovetail. It really don't matter how you do it as long as its done right.

"It don't matter how you do it as long as it's done right"  Part of the purpose of this forum is to share techniques with those with less experience.  From my (fairly extensive) experience machining parts, I look at this workholding and don't feel good about it.  So this is why I brought up the point I did.  If it works well for you go for it, but as a suggestion to others, I personally would not agree with it.

I know your happy with it and I don't mean to squash you feeling good about this, but it's just now an accepted way of workholding.  It's not strong, stable and doesn't allow for assurances of the barrel bore being perpendicular to the y -axis.

Jim

Offline 577SXS

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Re: Holding swamped barrel in vise
« Reply #7 on: October 23, 2020, 07:41:52 PM »
Jim,

I have extensive machining experience also. I worked as a Tool & Die maker for a large manufacturing company and did lots of prototype work. I've been machining for over 40 years. This set up is very rigid for the type of machining I'm doing. I have a jack on other end of barrel to hold it in place and I center the barrel on both ends of vise to get bore straight. As you said this part of the forum is for giving ideas and this was the idea I came up with for a quick simple solution for holding a swamped or tapered barrel. Anyway thanks for your comments.

Offline 577SXS

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Re: Holding swamped barrel in vise
« Reply #8 on: October 23, 2020, 08:37:19 PM »
I heeded Jim's points and I milled flats on my pins so that there is much more bearing surface to contact vise jaws. This will make it much more stable and less likely to give any issues. I made this setup for cutting dovetails in barrels only, not for heavy cutting.

Offline tiswell

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Re: Holding swamped barrel in vise
« Reply #9 on: December 09, 2020, 05:17:50 AM »
Another 45 year metal butcher here. It obviously works but IMHO is sub optimal. Use one rotating parallel on the moveable jaw and re-indicate. How long does it take vs fixing a buggered barrel. I could fill a book with stuff like this that has bit me in the rump.

Offline Maineshops

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Re: Holding swamped barrel in vise
« Reply #10 on: December 09, 2020, 05:34:20 PM »
A couple of pieces of sheet lead works for me in most cases.Dan

Offline DGB

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Re: Holding swamped barrel in vise
« Reply #11 on: December 09, 2020, 06:41:14 PM »
Re; holding swamped or tapered barrel:
I normally hold the barrel in two vee blocks.
The vee blocks nest the barrel and the vee block sides are still parallel to your vise jaws, works on tapered round areas as well.
Unless you are using a very tiny vise, there should be room for the vee blocks.
I have been doing this about 45 years, it works.

Regards,
Dave

Offline Majorjoel

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Re: Holding swamped barrel in vise
« Reply #12 on: December 09, 2020, 07:51:44 PM »
I wrap my barrel at the point of vise contact with an old bath towel.  Just thick enough to protect and thin enough to hold tight. 
Joel Hall

Offline Not English

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Re: Holding swamped barrel in vise
« Reply #13 on: December 17, 2020, 08:11:48 AM »
I don't worry about it. I prefer to lay out the slots on the bottom  barrel flat and mill by eye. I file the dove tail in as I inlet the underlug. I worked the last 20+ years as an Insttrument Maker at the University of Wisconsin. An Instrument Maker at the UW is a tool and dye maker that knows how to weld. It's not that I can't do what other people are talking about, I just find my method less prone to errors.

Dave

Offline BJH

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Re: Holding swamped barrel in vise
« Reply #14 on: January 24, 2021, 05:25:53 PM »
OK Iím going to add fuel to the fire. Since each dove tail is a one off operation. I simply use a card board u shaped shim at the narrow side of the barrel in the milling vise, it compresses and holds the barrel firmly. Gentle squeeze then use a level on the top flat to level everything up, then mill your pilot cuts with light cuts I usually use two or three passes. Done. I finish file the dovetail by hand. I doubt it takes me 15 min each. The card board used is non corrugated solid board, the stuff used on the back of notepads etc. Where there is a really heavy swamp I simply add layers. The u shaped shim keeps the narrow side centered and everything square visually. It takes just a small bit of judgement to estimate the thickness of card board you need, just remember it needs to compress, to do its job. Iím sure the springy vise on the Grizzley mill drill helps a bit too. When I worked in the machine shops we had a few milling machine vises that were too precise. We often used a shim on the moving jaw to help hold parts better. Thatís where I got the idea.  BJH
BJH

Offline Dennis Glazener

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Re: Holding swamped barrel in vise
« Reply #15 on: January 24, 2021, 09:11:42 PM »
I do much like BJ except I use old business cards, really high tech :)
It has always worked well for me.
Dennis
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