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mitee bite fixturing question

Cole2534

Diamond
Joined
Sep 10, 2010
Location
Oklahoma City, OK
Hello all,
This is my first foray in the low-profile clamping market and I'm not sure what I need/want exactly.

I'll be making a small fixture plate (steel or aluminum?) to hold 1.25" long pucks of 1-5/16" diameter 1144 Stressproof with the axis along Z. The plan is to cut a pocket in the plate approx .400" deep then apply a pitbull clamp to one side while I profile the OD of the part.

Why question is two fold- How do you know what style you want and what size you need? Right now I'm leaning toward pt#26060. Pitbull(R) Clamps | Mitee-Bite Products LLC.

I've emailed Mitee-bite, but thought I'd ask you guys as well.
 
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I don't have direct experience but I don't like this plan. A sawcut edge sitting in a pocket with only one contact point on either side of the stock (one pitbull and the pocket) while you profile it? I don't think I'd want less than three of those clamps per part otherwise I foresee chatter at best or launched parts.
 
Ya, I don't think it's so hot either but I wasn't sure how well these things worked. Maybe I should use the machinable kind and I can get more contact.
 
Hello all,
This is my first foray in the low-profile clamping market and I'm not sure what I need/want exactly.

I'll be making a small fixture plate (steel or aluminum?) to hold pucks of 1-5/16" diameter 1144 Stressproof with the axis along Z. The plan is to cut a pocket in the plate approx .400" deep then apply a pitbull clamp to one side while I profile the OD of the part.

Why question is two fold- How do you know what style you want and what size you need? Right now I'm leaning toward pt#26060. Pitbull(R) Clamps | Mitee-Bite Products LLC.

I've emailed Mitee-bite, but thought I'd ask you guys as well.
I'm not a fan of pitbull clamps on round surfaces.
I have used these and like them alot.
Machinable Fixture Clamps | Mitee-Bite Products LLC.
 
The pitbulls are powdered metal and hard. the 1/4-20 version will put over 1K lbs of force into the part. It will dent stressproof. The key is backing up the pitbull clamp with a hard surface behind it. Aluminum won't cut it. Even mild steel will develop wear that takes force away from the clamp.

Take a look at the examples on the mitee bite page, specifically how they back up pitbull clamps. Done correctly a pitbull will hang on to a lot, but it has to be designed correctly. They are an all or nothing deal.
 
How much clamping force you need depends on how much cutting force you wish to apply. So, are you profiling .01" off or a bit more? DOC? Etc.
 
I'm assuming you are holding the round part?

My 2 cents. I've absolutely screwed myself several times trying to make some kind of
fancy ass fixture with mighty-bites or other things, when a simple vise and some
soft jaws would have taken care of the job far quicker, even running less parts at a time.

I do absolutely everything I can to avoid having to play around with wrenches and screws
when trying to hold a part.. A vise is a half turn and a half turn. 2 parts out, 2 parts in.. DONE!


Quick story.. I had one part years and years ago at a different shop. Thousands of them.. I made these
cool little pallets that held 4 for the first op and 4 for the second op.. So 4 complete parts off the machine with every button push.

The pallets weren't big, maybe 8x10, I put nice handles on them so they were quick to move, and 2 de-sta-co clamps to clamp them in. I made 3 pallets...

I needed 2 people to run that machine.. Machine was running with pallet 1.. 1 person taking parts out of pallet #2, one person putting parts into pallet #3. It took 5 mighty bites (uniforce) to hold in the 8 parts (4 1st op, 4 2nd op). 2 people still couldn't keep up with the machine. And that wasn't even with deburring involved. That was a whole other deal, and all the exposed edges were deburred in the machine.. And to make it worse.. While running that job, the spindle in the machine decided it wasn't happy.. Went from 11k, to 7k down to having to run at under 3k.. And the 2 people still couldn't keep up with the machine.

I'm actually pretty damn proud of those pallets. It was an awesome concept, and if it was a longer running material, or there were more features in the part that took more time, it probably would have been a winner.. But it wasn't.. I tried to get fancy and I screwed myself.

I would have been far ahead in time, money, and manpower running them in strips across 2 or 3 vises..

Just something to think about. There is more than one way to skin a cat (who the hell came up with that saying? why the hell would I want to skin a cat?).

I'm assuming the parts would come out of rectangular bar easier, and you are running round because that's all you can get easily.
What are the "Box" dimensions of the part?

Think outside the box. That's how you make money as a machinist. There are million different ways to do a lot of things.
 
I would make the fixture with moving clamps on the sides, say 75% of the pocket on the fixed center and 25% in the clamp. The clamp should be clearanced so it only touches the parts and an 1/8" strip along the bottom where it touches the fixed center, held on with a single 5/16"-24 SHCS. Each clamp would hold 2 parts, all made from 6061 because it is light, easy to machine and will last for far more than 50 cycles. Clearance the center 15 degrees of the fixture or clamps so the parts don't make contact with them there, this will improve contact area. Make 2 fixtures, one each for op1 and 2.

2nd option is machinable Uniforce clamps but your fixture plate will have to be very thick and that much wedge clamp pressure will want to bow the fixture.

All said I doubt 200 parts is worth making fixtures for and I am very pro fixture vs vises.
 
I don't have direct experience but I don't like this plan. A sawcut edge sitting in a pocket with only one contact point on either side of the stock (one pitbull and the pocket) while you profile it? I don't think I'd want less than three of those clamps per part otherwise I foresee chatter at best or launched parts.

+1 I'd try to do them in pairs, the fixture doing all the support AND clamping work, no store-boughts. "low profile" would thus even allow rebated / sunken subject to where the cutter has to be.

Split shapes, one side a balanced arm with one draw-in mechanism per pair, my usual a simple cam - just not direct-acting, but moving the "vise jaws" (functional description...), rather.

Or just tool-up jaws for ACTUAL pull-down class vises.

I can put more already-paid-for 6" Gerardi modulars side-by-side than I own table-traverse, so four, max, and 2 pucks, each, easy, 3 - mebbe even 4 ? ... a tad more challenging as to grip distribution, but could was. Then there are dual station & centering vises in the world.

We don't yet know how tall the pucks, nor the depth of the features to be profiled within that budget, nor if at all balanced as to tool force, etc.


2CW

Several among the grown-ups will have better ideas...

:)
 
I'm assuming you are holding the round part?

My 2 cents. I've absolutely screwed myself several times trying to make some kind of
fancy ass fixture with mighty-bites or other things, when a simple vise and some
soft jaws would have taken care of the job far quicker, even running less parts at a time.

I do absolutely everything I can to avoid having to play around with wrenches and screws
when trying to hold a part.. A vise is a half turn and a half turn. 2 parts out, 2 parts in.. DONE!


Quick story.. I had one part years and years ago at a different shop. Thousands of them.. I made these
cool little pallets that held 4 for the first op and 4 for the second op.. So 4 complete parts off the machine with every button push.

The pallets weren't big, maybe 8x10, I put nice handles on them so they were quick to move, and 2 de-sta-co clamps to clamp them in. I made 3 pallets...

I needed 2 people to run that machine.. Machine was running with pallet 1.. 1 person taking parts out of pallet #2, one person putting parts into pallet #3. It took 5 mighty bites (uniforce) to hold in the 8 parts (4 1st op, 4 2nd op). 2 people still couldn't keep up with the machine. And that wasn't even with deburring involved. That was a whole other deal, and all the exposed edges were deburred in the machine.. And to make it worse.. While running that job, the spindle in the machine decided it wasn't happy.. Went from 11k, to 7k down to having to run at under 3k.. And the 2 people still couldn't keep up with the machine.

I'm actually pretty damn proud of those pallets. It was an awesome concept, and if it was a longer running material, or there were more features in the part that took more time, it probably would have been a winner.. But it wasn't.. I tried to get fancy and I screwed myself.

I would have been far ahead in time, money, and manpower running them in strips across 2 or 3 vises..

Just something to think about. There is more than one way to skin a cat (who the hell came up with that saying? why the hell would I want to skin a cat?).

I'm assuming the parts would come out of rectangular bar easier, and you are running round because that's all you can get easily.
What are the "Box" dimensions of the part?

Think outside the box. That's how you make money as a machinist. There are million different ways to do a lot of things.
Box dims are a cylinder 1.25" long, 1.313" diameter.

But I think you're right, don't get too fancy for this. If they come back and want a 1000 then it's time to re-evaluate.

Besides, I have 2 vises I can use. 4 parts per button push is gonna beat the hell of how I did them last go-round- 1 by 1 in a Bridgeport.
 
... want a 1000 then it's time to re-evaluate.

Sheesh. Thot you were already well above that level to even contemplate a bespoke fixture? A stash of jaw blanks is wot yah need.

Vise makers and jaw tooling are legion. Each of the survivors have proven their worth, modular, niche, or general-purpose, sole-player to tombstone, and a whole lot more than just the one time.

More than just the two vises has a fair reliable payback, 'coz time gone on amortizing a fixture has to see task-specific returns.

That time cannot be bought-back, exchanged, nor ratholed for a tougher to hit RDD, some future day.

Expand your arsenal of adaptability, be DONE with the job and better placed to bid the next one off the back of the third-best solution before you could even complete - let alone de-bug - the average first-choice fixture.
 
Sheesh. Thot you were already well above that level to even contemplate a bespoke fixture? A stash of jaw blanks is wot yah need.

Vise makers and jaw tooling are legion. Each of the survivors have proven their worth, modular, niche, or general-purpose, sole-player to tombstone, and a whole lot more than just the one time.

More than just the two vises has a fair reliable payback, 'coz time gone on amortizing a fixture has to see task-specific returns.

That time cannot be bought-back, exchanged, nor ratholed for a tougher to hit RDD, some future day.

Expand your arsenal of adaptability, be DONE with the job and better placed to bid the next one off the back of the third-best solution before you could even complete - let alone de-bug - the average first-choice fixture.
Half my pursuits in machining are academic. This particular product is of my design for a customer so I figured it'd be a good place to try to some high density fixturing rather than just brute labor.

Sent from my SM-G973U using Tapatalk
 
Half my pursuits in machining are academic. This particular product is of my design for a customer so I figured it'd be a good place to try to some high density fixturing rather than just brute labor.

Dreaming them up and executing them was challenging and fun. But I didn't use them but for proof

Production line worker-bees did that.

Otherwise, high-density fixturing can lead to brute labour, same as sex can lead to dancing or listening to rock music.

:)

Load, make chip, clear chip, unload, clear chip, repeat.
 
I did a pile of parts out of stainless similar to this, 1.125od and milled a .842 hex x .625dp. I had gotten 2 sets of the vice jaws for the .750 dia. versa clamps, made a set of my own as well. just used .750 steel buttons instead of the Mitee Bite inserts and milled 1.125dia spots for 3 parts per vice. Could do 9parts at a time and just unclamped each vice to load & unload.
 
Box dims are a cylinder 1.25" long, 1.313" diameter.

But I think you're right, don't get too fancy for this. If they come back and want a 1000 then it's time to re-evaluate.

Besides, I have 2 vises I can use. 4 parts per button push is gonna beat the hell of how I did them last go-round- 1 by 1 in a Bridgeport.


This is an easy small plate fixture, I would go with the machinable mitee bites and use one clamp to hold two parts.
 
Sheesh. Thot you were already well above that level to even contemplate a bespoke fixture? A stash of jaw blanks is wot yah need.

Vise makers and jaw tooling are legion. Each of the survivors have proven their worth, modular, niche, or general-purpose, sole-player to tombstone, and a whole lot more than just the one time.

More than just the two vises has a fair reliable payback, 'coz time gone on amortizing a fixture has to see task-specific returns.

That time cannot be bought-back, exchanged, nor ratholed for a tougher to hit RDD, some future day.

Expand your arsenal of adaptability, be DONE with the job and better placed to bid the next one off the back of the third-best solution before you could even complete - let alone de-bug - the average first-choice fixture.

I'm also in the vise camp with this one. Besides, if you mill sets of round jaws, you can technically use them on another job if you get another that requires that size diameter stock. We've got a huge assortment of round jaws from over the years.

You have 2 vises? I assume they are single vises (like a regular Kurt)?

If you want "higher density" with jaws, get a couple double station vises and have 4 sets of jaws, each with 2 pockets milled in them. Bam, 8 pieces on the table (4 1st op and 4 2nd op if you prefer)
 








 
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