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Thread: Springs for the Moxon

  1. #1
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    Springs for the Moxon

    Rather than sidetracking Chris' Moxon thread, I will respond to Tom's comment about springs for a Moxon here.

    Tom wrote: Since the wood you used is thick I would suggest you get some springs from the hardware store and put the springs in between the jaws. The threaded rod should go through the hole in the spring. Spring (s) can be cut with a dremel tool if need be. If springs are cut I would recommend washers at the end of the springs to keep the spring ends from cutting into the wood.

    The springs make the whole vise easier to work with.

    Tom is referring to the springs first described (as far as I am aware) by David Barron a few years ago. I discovered this video some months back, and posted my version of the springs. I have not seen any else mention using springs. As Tom notes, they are really useful. This may be seen in my recent video on lipped dovetailed drawers (they performed transparently for me now, but it was brought to my attention that they were working well).

    Video: https://www.youtube.com/watch?v=gk0pFLmS9Tk

    This is David Barrons version ...



    Note that David uses common "parallel" springs, that is, the sides of the springs are parallel.

    Here's my chop with the springs I used ...



    Note that they are triangular ...



    David needed to drill a recess for his springs to fold into in order to close up his chop. With the triangular springs, they fold into themselves, and there is no difficulty closing the chop ...



    What is the benefit? Well, as soon as you loosen a wheel, the chop opens up automatically. It also maintains the tension, that is, stays open, rather than flops about, as other chops tend to do. This makes it mush easier to open one side to the width of the board (to be dovetailed), and then use the other side to lock or unlock the chop ...




    Where did I get these springs? I found them in my workshop! A lightbulb went off, and the rest is history, as they say.

    Regards from Perth

    Derek
    Last edited by Derek Cohen; 04-04-2020 at 10:23 AM.

  2. #2
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    Madison, Wisconsin
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    McMaster Carr carries the same kind of springs as Detek used (and many more): https://www.mcmaster.com/springs/spr...ssion-springs/

  3. #3
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    Quote Originally Posted by Michael Bulatowicz View Post
    McMaster Carr carries the same kind of springs as Detek used (and many more): https://www.mcmaster.com/springs/spr...ssion-springs/

    Thanks Michael and Derek.
    "If you have all your fingers, you can convert to Metric"

  4. #4
    Derek,

    What is the free length of your springs and what is the spring at solid?

    Die springs are sized by the hole size that they will drop into. And it looks as though this holds true with light springs also. The rod or hole diameter is important because it determines what size stripper bolt or spring retainer will fit inside. In case of light springs it will be outside diameter minus 2 wire sizes. So if one has a 3/4 shaft a I inch OD spring is needed.

    Spring life is determined by the amount of, in this case, spring compression and the life decreases dramatically as it nears solid. Also a spring should have at least 1/8 inch preload to be effective. I am guessing that a lighter spring would require more preload.

    So the working space between the two jaws come into play because if the working ares is 2 inches, a longer spring is needed than if clamping a 1/2 or under thick piece of material. In other words a 15/16 dia. spring will fit in a 1 Inch hole and the depth of the holes is determined by if the spring is 2 inches long than the combining depth should be 1 7/8ths but I would put more preload on the springs because it is easier to drill the hole s deeper than to shim the holes to get more preload. If cutting the springs then I would size the hole for a metal washer. The spring will stay in place because the threaded rod is passing through.

    One last note if you want the springs to last then store the vise in the open position. In my case it is a 15 mile trip one way to get a new spring and what happens if it it is not in stock. Leave the vise open or have extra springs.

    I hope this helps someone.
    Tom

  5. #5
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    Thanks Michael and Tom- I’ve found McMaster can be a rabbit hole deeper than a sharpening thread!
    "You can observe a lot just by watching."
    --Yogi Berra

  6. #6
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    I tried and abandoned the springs as shown. The required enlargement of the clearance hole in the chop was enough to allow easy adjustment.

    Instead, a bronze bushing was adapted from out local plumbing supplier. The cast iron wheels interface on a heavy Delrin washer, as they were scoring the bronze.

  7. #7
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    Quote Originally Posted by Jim Matthews View Post
    I tried and abandoned the springs as shown. The required enlargement of the clearance hole in the chop was enough to allow easy adjustment.

    Instead, a bronze bushing was adapted from out local plumbing supplier. The cast iron wheels interface on a heavy Delrin washer, as they were scoring the bronze.
    Jim, I get the impression that you believe the springs are to aid smoothness of movement. They are not. The springs are to push the chop back, which aid in opening the chop. I used bronze bushings for smoothness. They have nothing to do with this topic.

    Regards from Perth

    Derek

  8. #8
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    A statement of the obvious, first.
    It's unlikely I'll ever cut many dovetails.

    The not so obvious: my Moxxon is built directly into the bench, made of local Ash. The movable chop is made of two riftsawn pieces (top half and bottom half with opposing grain) - riftsawn.

    At 27" between the "bolts" it moves enough to bind with Seasonal humidity changes. The chop is smaller than the mating front skirt.

    It "moves" relatively faster than the bench itself.

    After two months with the springs installed, it jammed again, trapped between the bolts. I asked my mentor how to approach the problem.

    He suggested making one side "tight" and creating slightly more clearance on the other. Until the assembly may be adjusted. This was done without the springs, for expedience.

    I found that with the left hand bolt "loose" the springs were surplus to requirements and one less thing to clean.

    This allows me to pinch boards, drawers and long edges in place and tighten the works down on the other side, like leaning into a closet door.

  9. #9
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    Quote Originally Posted by Tom Bussey View Post
    Derek,

    What is the free length of your springs and what is the spring at solid?

    Die springs are sized by the hole size that they will drop into. And it looks as though this holds true with light springs also. The rod or hole diameter is important because it determines what size stripper bolt or spring retainer will fit inside. In case of light springs it will be outside diameter minus 2 wire sizes. So if one has a 3/4 shaft a I inch OD spring is needed.

    Spring life is determined by the amount of, in this case, spring compression and the life decreases dramatically as it nears solid. Also a spring should have at least 1/8 inch preload to be effective. I am guessing that a lighter spring would require more preload.

    So the working space between the two jaws come into play because if the working ares is 2 inches, a longer spring is needed than if clamping a 1/2 or under thick piece of material. In other words a 15/16 dia. spring will fit in a 1 Inch hole and the depth of the holes is determined by if the spring is 2 inches long than the combining depth should be 1 7/8ths but I would put more preload on the springs because it is easier to drill the hole s deeper than to shim the holes to get more preload. If cutting the springs then I would size the hole for a metal washer. The spring will stay in place because the threaded rod is passing through.

    One last note if you want the springs to last then store the vise in the open position. In my case it is a 15 mile trip one way to get a new spring and what happens if it it is not in stock. Leave the vise open or have extra springs.

    I hope this helps someone.
    Tom, the length of the springs - that is, with the wheels relaxed and measuring between the chop and rear - is 1 1/4 to 1 1/2".

    Regards from Perth

    Derek

  10. #10
    Derek,

    I want to know what length of the spring is a solid. That is when the spring is compressed as far as will go. Also what is the thinnest stock you commonly use?
    Tom

  11. #11
    (At 27" between the "bolts" it moves enough to bind with Seasonal humidity changes. The chop is smaller than the mating front skirt.)

    If it sticks with seasonal humidity changes drill out the holes, they should elongated anyway. If it is to tight the springs can't work.
    Tom

  12. #12
    Join Date
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    Quote Originally Posted by Tom Bussey View Post
    Derek,

    I want to know what length of the spring is a solid. That is when the spring is compressed as far as will go. Also what is the thinnest stock you commonly use?
    Tom, this is the when the spring is compressed. The chop will close up against the rear ...



    This is with the springs loosened off - one side is 1 1/2" and the other is 1 1/4" ...



    There is no recess into the wood for the springs (as with David Barron's version). Only the lining is cut away ...





    Epoxy is used to hold one end, and centre it. The other end is, obviously, free.

    Regards from Perth

    Derek

  13. #13
    I guess that is what I wanted to know, which is if you made it so the chop would close against the rear.

    If a person compresses the the spring to solid then he knows how deep to counterbore the holes so that the vise can close. A spring will not last going to solid and staying there which could happen with this type of vise so it is recommended collapse a spring more that 75 per cent of its travel. Example: you have a 2 inch long spring in the free state and at solid it is 1/2 inch then the travel is 11/2 inches. If you want the spring to last as long as you do, then fix it so the spring never gets collapse more than 75% . That would be 1.5 X .75 = 1.125 (11/8)

    So it you have a 1 inch diameter spring drill a 1 inch diameter ( flat bottom drill a forstner drill works the best) 1/2 inch deep ( actually 9/16 but it isn't rocket science actually 5/8 will work fine the spring just wouldn't open the chop as far. in both the chop and the solid jaw. That way the spring will be contained. If not contained the loose end of the spring will tend to flop around and either the chop or solid jaw will have to be made thicker to accommodate the spring depth.

    If you are using a 3/4 acme threaded shaft then a 3/4 hole can be drilled the chop, the chop can rest on the threads for up and down movement. But the chop needs to be elongated so it can open and close without binding.

    I will finish after breakfast.
    Last edited by Tom Bussey; 04-07-2020 at 10:06 AM.
    Tom

  14. #14
    In Derek's posts he used metal tubing in the holes. This allows for the clearance on the thread so that the chop can move more freely. Metal on metal also allows movement more freely than wood on metal which is the best of both worlds.

    In other wards with the springs installed when the chop is loosened the part can be removed easily and the chop cannot wiggle and close on its own or if the chop is bumped it will remain open to the exact position it was left in.

    All in all the springs added on the moxon vise are a great upgrade. Not necessary but if done right they will improve function and it will be noticeable if the vise is used a lot.

    I hope what I had to say helps.
    Tom

  15. #15
    I got to thinking about what I wrote and since my vise is a little different from most. If a person needs to counter bore for a spring it would all need to be in the chop. The chop would be backed up by the washer and the hand wheel to it wouldn't be s a strength issue. Just correcting myself.
    Tom

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