what clamps work well to hold work to fixture plates without holes?
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    Default what clamps work well to hold work to fixture plates without holes?

    What kind of clamps work well to hold work against side cutter forces when the work is temporarily clamped to an angle plate? This is just an initial setup, i.e. before any mounting holes have been created.

    I just had some work shift while trying to hold it to the plate with c-clamps. I was using the horizontal spindle, trying to countersink bolt holes to mount it to the plate (using an end mill and G02 due to lack of room for a countersink). I ended up doing the countersink on the drillpress and remounted it to the newly threaded holes in the plate, but I still need something with some clamping force, since this problem comes up regularly when using the horizontal spindle.

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    I don't understand what kind of machine you are using/scale of your problem, but one trick I have come up with and use often is to clean both surface well and stick a clean sheet of printer paper between a smooth material and a smooth table surface when my clamping arrangement is sloppy or half assed.

    I've done some real sketchy stuff with success using the paper trick.

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    I've used just about everything, C clamps, kant twist clamps, strap clamps, even vise grips and woodworking clamps. I think you need more and larger C clamps than strap clamps because they don't create as much force because of the coarser screw pitch.

    Edit - Business cards and chipboard from legal pads work too. I've also used that in vise jaws.

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    I have done the "paper trick," but with soft sheet copper between a rough cast surface and the vise jaws or an angle plate. I like Kant-Twist clamps or the old Enco brand copies, but my first choice is always the step blocks and strap clamp set wherever possible.

    Larry

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    Also,the thing about c-clamps is that they can rock or twist. I have a range of sizes of kant-twist clamps, and I use them for welding. Also some welding vise grips. But I really was looking for a clamp that would generate the kind of force you get with step blocks and a clamp set, when you are clamping to a fixture plate perpendicular to the table. Maybe the solution is to drill and tap holes into the fixture plate, I know that is done a lot.

    A hydraulic c clamp would be ideal, but not one that requires a porta-power.

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    There are heavy duty forged C clamps that will easily give you the kind of clamping pressure you’d get from step blocks and strap clamps.

    If your angle plate is slotted, through bolts with strap clamps make sense. If it’s not slotted, I’d consider drilling and tapping for studs or screws to use with strap clamps.

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    Quote Originally Posted by rimcanyon View Post
    Also,the thing about c-clamps is that they can rock or twist.
    Not "can". "Will".

    Even heaviest and most expertly forged are still but single-plane. Use them at a fraction of their yield point to avoid slant of the screw and they are OK, if only barely.

    I have a range of sizes of kant-twist clamps,
    Of course. Size and beef side, they have TWO planes of working members, not just the one. The name is apt.


    Maybe the solution is to drill and tap holes into the fixture plate, I know that is done a lot.
    Not always essential. Or not very MANY tapped holes Clamp a stout plate or one or more BARS with the drilled and tapped holes wherever and at whatever spacing or angle "works" to support step-block strap and toe clamps, even Mitee-bites.

    Now your "means of attachment" - better clamps still on the menu - for the bar are out of the way, and the clamps for the work are optimized for that item and tasking...

    All without (yet) having to fab a "bespoke" fixture that is not flexible / general-purpose.. when you are only doing onesies or fewsies anyway.

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    Another solution is to fit ''stop blocks'' so the part can't slide about.

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    There's G clamps and there's G clamps 🙃 I have CI Chinese ones that will do for light jobs. Then I have boilermakers' Cramps which are pretty bombproof,Williams and Lion. Carver clamps are better than ordinary G clamps,too.

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    Quote Originally Posted by TedinNorfolk View Post
    There's G clamps and there's G clamps �� I have CI Chinese ones that will do for light jobs. Then I have boilermakers' Cramps which are pretty bombproof,Williams and Lion. Carver clamps are better than ordinary G clamps,too.
    Ve haf zimmilr.... bridge, beam, other heavy Iron assembly work, etc.

    Still fighting geometry & physics -- a screw or pad that wants to enhance twist, and a single plane with the screw trying to lean.

    "Beam" clamp at least is brutally SHORT, "may" have a wide foot. OTOH, they are meant to HANG stuff, have piss-poor clamping pressure as far as holding MATERIALS in-place against cutting forces.

    One can only "fight" the need for but so long with clever-devil clamping rations before one or more different PLATES - drilled and tapped ELSE tee-slotted - become less work?

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    Cam type disks, block and wedge, sacrificial top plate,
    Mark

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    Have you looked at Knuvises . Have used them successfully when I had to modify sheet metal housings and used them to clamp them to angle plates. Bill

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    None of the above for me. If you're doing work that creates enough tool pressure such that it can move the work, you should have the clamps only providing clamping pressure, not resisting side forces. Use a threaded in (to the angle plate) or otherwise fitted in push block (or multiple, placed directly over any parallels) from the top, pushing the work down onto the parallels or table surface. Then add two kickers from the sides pushing against each other. Your work won't go anywhere.

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    Quote Originally Posted by eKretz View Post
    None of the above for me. If you're doing work that creates enough tool pressure such that it can move the work, you should have the clamps only providing clamping pressure, not resisting side forces. Use a threaded in (to the angle plate) or otherwise fitted in push block (or multiple, placed directly over any parallels) from the top, pushing the work down onto the parallels or table surface. Then add two kickers from the sides pushing against each other. Your work won't go anywhere.
    ACK. Same rules as H mill, V mill, planer, shaper, rotab.

    That the plate is at an angle mattereth not. Cutting force is what it says it is.

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    To gild eKretz's lily, I'd suggest fences (aka hard stops) on two sides of the workpiece, and two pushers on the other sides of the workpiece. Simply put, I don't like the physics of single pushers on opposite sides of a workpiece pushing against each other.
    Last edited by John Garner; 03-10-2021 at 07:47 PM. Reason: Correct spelling

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    Quote Originally Posted by John Garner View Post
    To gild eKretz's lily, I'd suggest fences (aka hard stops) on two sides of the workpiece, and two pushers on the other sides of the workpiece. Simply put, I don't like the physics of single pushers on opposite sides of a workpiece pushing against each other.
    I guess a set of threaded holes in the angle plate is the requirement then. I have a good assortment of potential fences, but what do you have in mind for pushers? Mitee Bite toe clamps or ??

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    Quote Originally Posted by rimcanyon View Post
    I guess a set of threaded holes in the angle plate is the requirement then. I have a good assortment of potential fences, but what do you have in mind for pushers? Mitee Bite toe clamps or ??
    - Hunk of Tee-slotted material as a sub-plate? At which point.. you've sacrificed some "daylight" as well as added mass, but can use all the same goods as you would use on a(ny) horizontal milling table.

    - Two-piece vise? Of the general type as:

    TTC 8" Jaw Width, 3-1/4" Jaw Depth 2 Piece Machine Vise | 61-401-248 | Travers Tool Co., Inc.

    Beyond that? "We" do not know enough about the work nor the stock..

    Steel is cheap. Usually. Unless you've made scrap out of it?



    Time is dear. Always. ESPECIALLY when wasted.

    I'd JF make a sub-plate to suit, add MORE holes to it if/as/when a new tasking was best served by that. Make ANOTHER sub-plate if/as/when..

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    One of my most-used pushers, originally designed to fit an optical bench having 1/4-20 tapped holes on a 1 inch x 1 inch grid, started life as a length of 1/2 inch square aluminum bar. Cut into 1 1/2 inch lengths, drill a pair of 1/4 inch clearance holes 1 inch apart through one side, and drill and tap 1/4-20 through the adjacent side, centered between the through holes.

    Screw the bar to the table using the clearance holes, and thread a screw through the tapped hole to put a pusher screw where you need it.

    A variation is to angle the tapped hole on a 1 part in twenty slope to produce a little bit of a toward-table force.

    In either case, I preferred a "round point" screw and used a slip of nylon or similar plastic between the screw tip and workpiece to avoid marring the workpiece surface.

    A variation of the theme uses a 2 inch piece of bar stock, and adds a third clearance hole to allow the clamp body to be installed on the grid diagonal.

    It should go without saying, but the design scales up well, and stronger materials allow higher loading.

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    Quote Originally Posted by John Garner View Post
    One of my most-used pushers, originally designed to fit an optical bench having 1/4-20 tapped holes on a 1 inch x 1 inch grid, started life as a length of 1/2 inch square aluminum bar. Cut into 1 1/2 inch lengths, drill a pair of 1/4 inch clearance holes 1 inch apart through one side, and drill and tap 1/4-20 through the adjacent side, centered between the through holes.

    Screw the bar to the table using the clearance holes, and thread a screw through the tapped hole to put a pusher screw where you need it.

    A variation is to angle the tapped hole on a 1 part in twenty slope to produce a little bit of a toward-table force.

    In either case, I preferred a "round point" screw and used a slip of nylon or similar plastic between the screw tip and workpiece to avoid marring the workpiece surface.

    A variation of the theme uses a 2 inch piece of bar stock, and adds a third clearance hole to allow the clamp body to be installed on the grid diagonal.

    It should go without saying, but the design scales up well, and stronger materials allow higher loading.
    Galis, Morgantown/Westover West Virgina had a stiffer means, "back in the day".

    First tasking, my first day on the job. Foreman thought it was funnier than naked in church that I walked in the door with but ONE micrometer in my box. A 0" to 3/8" B&S. Well? Hearing aids were SMALL!

    First tasking is to take our shift's turn (we were working 3 shifts) at machining the ~ 46-inch OD turntable bearing fit.. on a 100-ton crane body!

    It was affixed to the table's tee slots with torch-cuts off massive HRS Ell, bolted.

    The many struts between crane body weldment and those Ells?

    Were STICK WELDED!

    To be cut-loose later with big air-powered angle-grinders.

    F**ker didn't budge under cutting forces!

    "That scales, too" in the era of ubiquitous Tig ... and cheap. Been seen "right here, on PM" for goods you can easily hold in one hand, too.

    So, too, brown "stick" shellac.. low-eutectic solders, and ceramics, fired. Since ancient pre-epoxy-age.

    Grasp with whatcha GOTS.. not what you only WISH you gots!


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