Building a fixture for the Bridgeport

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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azscj
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Building a fixture for the Bridgeport

Post by azscj »

Its been a while since I posted here on the forum. Been learning to use the Bridgeport I have, and still learning. One of the best tools I own. The current project is to restore old smog pumps that were used on the late 60's early 70's Mustangs for my restoration shop. These pumps were used on Cobrajet's and Boss Mustangs. Most people just media blast the case, but I wanted to bring the finish back to as close as original as possible. I have a tumbler and wanted to find a way to machine the edges like they were when new.

Disassembled to the bare case:
Image

What I wanted to find is a simple way to fixture this to my Bridgeport table and was thinking of using a piece of angle iron for mounting like I have here in the pictures. Maybe drill out a hole so that I can mount the case with some large washers and a bolt to the angle iron. And then clamp the angle iron to the table and use a fly cutter to duplicate the original cuts. Does this sound reasonable or is there some miracle wonder widget I can use for clamping? The cuts are only cosmetic so the tolerances are not as import as the aesthetics of what the fresh cuts look like. Appreciate any advice.

Image

Image

Image
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Harold_V
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Re: Building a fixture for the Bridgeport

Post by Harold_V »

azscj wrote:What I wanted to find is a simple way to fixture this to my Bridgeport table and was thinking of using a piece of angle iron for mounting like I have here in the pictures. Maybe drill out a hole so that I can mount the case with some large washers and a bolt to the angle iron. And then clamp the angle iron to the table and use a fly cutter to duplicate the original cuts. Does this sound reasonable or is there some miracle wonder widget I can use for clamping? The cuts are only cosmetic so the tolerances are not as import as the aesthetics of what the fresh cuts look like. Appreciate any advice.
Lose the idea of using angle iron. It is almost never square, straight, or flat, although it may be close. You'll alter the features of those pumps beyond a cleanup cut if you don't duplicate the original setups quite closely.

Here's something to consider, if you have more than one to do, and have not blasted yet. Clean the surfaces well you prefer to not blast (use a file, draw style, to remove dings on the faces that won't get blasted), then attach plates, so you can blast the balance of the parts without altering the edges. That would be far better than trying to machine them after blasting, which, most likely, will result in the need to blast them again, to remove handling marks.

If you'd like to machine those which are already blasted, angle plates are used for such work. That's what I'd recommend. You can fasten items to them via the slots they have, or even with large C clamps. With care, you can take generous cuts when your part is properly restrained by a pair of clamps (or more). It is an acceptable way to hold such parts, although you should exercise care.

You could probably make a decent angle plate from a piece of heavy angle iron, but it would require considerable work on your behalf. To limit chatter in cuts, it shouldn't be light weight. Cast iron is the metal of choice, because of its dampening qualities.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
azscj
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Re: Building a fixture for the Bridgeport

Post by azscj »

Great input Harold. Much appreciated. Just an additional picture to help illustrate what I am trying to achieve. For sure the final result should have the fresh cuts because it duplicates what an original smog pump had and also so I can stamp in the correct date codes. I like the idea of a slotted angle plate. I could use that for other projects then as well. I only have a small one now so I should be able to find a larger one thru Enco or MSC catalog or is there a better source?

Here is a picture of an original that has never been installed on a car to show the finish.

Image
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Harold_V
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Re: Building a fixture for the Bridgeport

Post by Harold_V »

azscj wrote:Great input Harold. Much appreciated. Just an additional picture to help illustrate what I am trying to achieve. For sure the final result should have the fresh cuts because it duplicates what an original smog pump had and also so I can stamp in the correct date codes.
I wasn't sure if the cuts I see were what needed to be refreshed, but I understand now. My thoughts wouldn't apply much in this case, as you'd have a tough time trying to plate those cuts. The end plate would serve to preserve the keen edge if you blasted, but it won't serve you for the cuts I see. For that, you most likely will have to make the setup you described.
I like the idea of a slotted angle plate. I could use that for other projects then as well. I only have a small one now so I should be able to find a larger one thru Enco or MSC catalog or is there a better source?
There may be a better source (or not), but there shouldn't be any particular issue in buying from either of those two sources, with Enco likely having the better price. A lot of their provisions are sourced from China or other countries that may or may not have the greatest reputation, so it's hard to say if what you'd receive would be in keeping with what you'd like, but I'm having a hard time believing that it wouldn't be better than a piece of angle (unless you're willing to do the machining to improve its qualities).
Here is a picture of an original that has never been installed on a car to show the finish.
You most likely won't be able to duplicate that finish, as it's permanent molded. Even a vibratory tumbler won't do it, but you should be able to produce a very acceptable finish (although not prototype).

If a fine satin finish is acceptable, you can blast with (fine) glass bead, or even research walnut shell. Even soda blasting may work. I have no experience in that arena. Most likely you'd still have to remachine the areas I see, although if they are pristine (unlikely), they can be masked easy enough. Cleaned properly (no oil), vinyl electrical tape can serve to mask the area. You can also research the thin self adhesive rubber masking material that is used for engraving headstones. It's easy to carve, and sticks well. I use that material to line the interior of my blast cabinet, to prevent creating holes. It is amazingly resilient, even against aluminum oxide.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.
azscj
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Re: Building a fixture for the Bridgeport

Post by azscj »

Thanks for the insight Harold. I will work on putting this together and follow up with a progress report when I have something to show for it.
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GlennW
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Re: Building a fixture for the Bridgeport

Post by GlennW »

Looks like it could be held in the vise for what you want to do.

Just make some taller jaws for the vise if needed.

Hard to tell from the pics though.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
earlgo
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Re: Building a fixture for the Bridgeport

Post by earlgo »

Take Harold's advise and buy a slotted plate.
Machining an angle is a LOT of work and your time would be better spent doing your original project.

Image

I only did this one because I wanted to mount a vise vertically and commercially finished angle plates were not big enough. Additionally, the vise was mounted on the 'dumb' side of the angle. Even more work.

--earlgo
Before you do anything, you must do something else first. - Washington's principle.
azscj
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Re: Building a fixture for the Bridgeport

Post by azscj »

Ok....I will get a slotted angle plate. Besides, I can always use that for other projects which is a big bonus.
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BadDog
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Re: Building a fixture for the Bridgeport

Post by BadDog »

If you have the time and inclination (and opportunity), check out some surplus shops. I found a large Taft Pierce (big $$$$) angle plate, hand scraped and in a protective box. Heavy enough I can barely dead lift it onto my mill (roughly 14"x14" or so and VERY beefy). And it's hand scraped on all reference surfaces. Beautiful piece, and I paid only about $50 for it. Some surplus want twice that for a 6" rough machined import, and won't listen when you explain to them it's barely better than a piece of angle iron. But there are jewels hidden among the dross, and much of the time they don't know which is which. I picked up some premium name box and angle "knee" fixtures as well.

If no other opportunity presents, Phase II is a good option. "Tools for Cheap" also seems to have a cut above and good service rep. I've even got some no-name imports that are actually ground (some appear just fly cut on critical surfaces) and not too bad. I use those mostly for rougher work where there is risk to the fixture, and extra rigidity and accuracy are not required.
Russ
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azscj
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Re: Building a fixture for the Bridgeport

Post by azscj »

Russ....so not sure about any local shops that have surplus. Are you saying "Tools for Cheap" is a good place locally....I never been there. Don't see them on the internet. Moore Tools is the only place I know that deals in used tooling and some new equipment. Appreciate any advice.
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BadDog
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Re: Building a fixture for the Bridgeport

Post by BadDog »

Not local. http://www.tools4cheap.net/

But a quick looks didn't produce an angle plate.
Russ
Master Floor Sweeper
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