AmericanLongRifles Forums
General discussion => Shop Made Tools => Topic started by: 577SXS on October 23, 2020, 12:08:47 AM
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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.
(https://i.ibb.co/KxNxRNj/IMG951243.jpg) (https://ibb.co/N212Q16)
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For manual milling I use a similar aluminum block. Mine is just shaped on the backside rather than having a pin, though. I don’t 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 isn’t too rigid or secure.
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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.
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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.
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I just rotate my vise. Maybe your vise is fixed?
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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.
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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
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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.
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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.
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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.
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A couple of pieces of sheet lead works for me in most cases.Dan
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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
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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.
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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
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OK I’m 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. I’m 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. That’s where I got the idea. BJH
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I do much like BJ except I use old business cards, really high tech :)
It has always worked well for me.
Dennis