Making Cams and Cam Clamps

making your own clamps has many advantages obviously one of them is saving money I can make three to four of these for what it cost me to buy just one of the commercial version and you can make a lot of them in a very short period of time they demand some Precision but they are very simple depending on what you make the bar out of there are just three to four wooden Parts but they will deliver all the pressure you need and will do so without marring or denting your work no need for calls to protect your projects from metal Jaws finally these cam clamps are remarkably quick to apply just set the Jaws where you want them and throw a lever [Music] how most clamps apply pressure by using screws but this particular clamp uses a cam screw is a wedge wound around a cylinder but a cam is a wedge wound around a disc turn the disc and the wedge applies increasing pressure against the movable jaw bending it in the direction of the fixed jaw anything caught between the Jaws will beg for mercy help me you can make these clamps any size you need I made these with a five inch throat and a 12 inch capacity that's 13 by 30 centimeters because I find that that's the size that I need the most for the type of woodworking that I do these days which is a little bit of everything you can make them out of scraps of wood provided the wood is reasonably hard with a very straight tight grain we've used hard and soft maple red and white oak Birch even a little purple heart for the Jaws the bars and the cams the bars on the clamps that we'll be showing today are mostly Steel bar stock and steel conduit now you can make them out of wood if all you need is a light duty clamp but I would use a very hard wood like rock Maple or Birch if you want a round wooden bar use a dowel this is three quarters of an inch or 19 millimeters in diameter if you want a rectangular bar make it at least one quarter inch thick and one and one quarter of an inch is wide this will give you the rigidity you need your choice of bar material also affects the hardware you need if you decide on a round bar steal conduit or a wooden dowel you'll need a small Carriage bolt washer and wing nut to lock the movable jaw in place if you go with a rectangular steel bar you'll need four roll pins two in the fixed jaw to hold it in place and two in the movable jaw to keep the steel bar from biting into the wood with a rectangular wooden bar all you need is a single roll pin to serve as the pivot for the cam fair warning if you select the steel bar stock pay very careful attention to the dimensions especially the thickness and the width this material is only casually acquainted with the dimensions on the spins and in all probability it won't match the dimensions I have in the plans so you'll have to make minor adjustments [Music] for the rectangular bars either wood or metal these pass through rectangular mortises in the Jaws it's easiest to make these mortises by cutting dados into two pieces of wood and then gluing them together when cutting the halves book match the grain this will give you the most stable Jaws number of the pieces as you cut them and then divide them into sequential pairs one and two three and four and so on then Mark the adjoining edges and the surfaces that you will be gluing together measure the width and thickness of the bar stock then set up your router or dado to cut a data 1 8 inch or three millimeters wider than the bar and half as deep as the bar is thick cut two matching dados in each pair of jaw halves quick tip if you cut the dados too deep simply glue some shims in the bottoms apply a finish to the inside surface of the dados be careful not to get any finish on the surfaces that you will glue together glue up the jaw halves the assembled jaw should be slightly wider and longer than shown in the plans to give you some extra stock to trim let the glue cure for 45 minutes to an hour then poke a bar through the mortise to remove any glue squeeze out it will be much easier to do this now while the glue is soft then after the glue becomes fully cured when the glue has cured completely trim the Jaws to their final size keep the mortises centered in the Jaws if you're making clamps with round bars all you have to do is drill a couple holes in the Jaws once again carefully measure the stock the manufacturer of dows can be fairly capricious when it comes to the dimensions it's much better for conduit but we had to invest in a 23 32nd inch drill bit it wasn't all that expensive but it's something to consider if you're on a budget in addition to the holes for the bars drill small holes near the ends of the movable Jaws for the carriage bolts that will pinch the wood together around the bars then cut narrow slots through the bar holes extending from the ends of the Jaws past the holes at least a half an inch or 13 millimeters into the Jaws lay out the recesses in both the fixed and the movable Jaws you can make these recesses with either rounded or beveled Corners I'm going to put beveled corners on this set of Jaws because they're easier cut each recess on a bandsaw if you're making the rounded Corners you'll have to use at least the 3 16 inch blade to be able to turn the radius sand the surfaces of the recesses to remove the saw marks the cam lever is mounted in a blind Groove that is a Groove that is closed at one end in the movable jaw there are two ways to make this groove you can cut it with a dado blade clamp a stop to the fence to stop feeding the jaw when the groove is long enough this will create the blind end and will keep you from cutting through the mortise or you can make the groove in a router table with a straight bit make the groove in multiple passes cutting just 1 8 inch or three millimeters deep with each pass once again use a stop to create the blind end the movable jaw has a thinned out face or finger that the cam bends about a quarter of an inch towards the fixed jaw to make the bendable part first Mark out the finger on your jaw then drill a small relief hole at the end of the finger this tiny hole will keep the grain just past the finger from splitting when you throw the cam then cut the Finger by sawing the jaw to the relief hole okay [Music] itself from a very hard wood with very straight grain to make it extremely durable make it out of hardwood plywood glue up three layers of hardwood alternating the grain direction of each layer this cam is made from Oak and purple heart plywood hard to find at your lumber yard and very unnecessary but it looks great the plans include a full-size template for the cams all you need to do is cut them out stick them to the stock and do a little cutting and drilling however if you want to make these clamps a different size or if you want to design cams for a different jig altogether there are a few things that you should know there are many different ways to make cans the traditional method is to draw a curve whose radius increases along its length a spiral to draw this spiral you need a pencil a string and a dowel tie a knot in the end of the string put the point of the pencil through the knot and draw the curve as the pencil winds the string around the dowel as it winds the radius of the Curve will change the size of the dowel determines how quickly the radius increases or decreases this spiral was drawn with a quarter inch dowel the spiral with a 3 8 inch dowel you need to determine how swiftly you need the radius to change as the cam rotates of course you can sidestep all the strings and dowels and stuff by simply drawing a circle with an off center pivot in most cases this will work perfectly well but in this particular project it may give you some problems this is one of the Spiral cams that I made as I rotate the cam it contacts a single point on the lever that it is lifting in your mind's eye draw a line from the point of contact to the pivot don't let Travis do it for you on his magic video editing software no matter where you rotate the cam the line will always be radial to the pivot the force of pressure generated by a spiral cam will always be in line with the pivot this cam is the circle with the off center pivot as I rotate the cam it lifts the lever just the same as the spiral cam but the point of contact walks back and forth on the lever depending where I stop the cam the force of pressure may or may not be in line with the pivot now just what difference could this make well if the clamping pressure is not radial to the pivot the cam may not hold that pressure it will slip come loose and terrible things will happen on a spiral cam the clamping pressure is always radial to the pivot the cam stays where you put it and life is good life is good life sucks dead toads [Music] you don't have to worry about any of this if you bought our plans we provide full-size templates for spiral cams along with a simple formula for designing your own there you have all the wooden parts now if you've chosen to make wooden bars either round or rectangular glue the fixed Jaws in place I've reinforced these glue joints with dowels probably unnecessary but it looks cool now it's time to apply a finish to all the wooden surfaces I'm using a wipe on poly for this because it dries quickly and it won't build up on the surface over much a hard wax oil finish might also be a good choice for this particular project it will protect the parts and keep them moving smoothly the cam lever in the movable jaw pivots on a roll pin to install this roll pin you need to drill a 1 8 inch or three millimeter hole in both the movable jaw and the cam lever if you haven't already done so the full-size template that we provide with our plans shows the location of all the holes you need however because these holes must be located precisely double check their positions with a ruler before you drill Mark the hole by making an indentation with an awl use a brad Point bit if you have one then use the indentation to catch the point of the bit insert the cam in its grooves and line up the holes then drive the pin through both the jaw and the cam with a hammer keep the groove in the roll pin facing away from the job face as you do this that way when the pressure is applied the cam will have a solid surface to rotate a pawn [Music] jaw to a metal bar first insert the bar into the mortise then use toothpicks as wedges to keep the bar tight and square to the jaw drill two holes through the assembled jaw and bar then drive roll pins through the jaw and the bar just as you did when assembling the cam lever to the movable jaw mounting a movable jaw depends on the shape of the bar if you're using a round bar simply insert a carriage bolt through the small hole in the end of the bar where you've cut the slot and then add a washer and a wing nut to adjust the position of that jaw slide it to where you want it and tighten the wing nut if you've made a rectangular wooden bar you shouldn't have to do anything just simply Slide the jaw onto the bar and it should hold just fine however be careful never to wax the wooden bar and if you made the bar from woods with natural oils you may have to result to the slot and the carriage bar that I used with the round bars and then you just simply tighten the jaw in place if you're using a rectangular steel bar you'll need to install two more roll pins in the movable jaw these serve two purposes they keep the Jaw from sliding on the steel bar and they keep the steel from biting into the wood and wallowing out the mortise measuring Center to Center the roll pin should be the same distance apart as the width of the bar plus the diameter of a roll pin in practice however this wasn't quite enough because our small drill bit occasionally drifted in the hard wood to be able to compensate we added just a smidge to this measurement note that the outboard pin the one closest to the end of the jaw should be near the top Edge the inboard pin should be close to the bottom Edge Mark can drill the holes for the pins and drive them into the jaw the grooves in the pins should face the mortise this will give each pin two points of contact with the bar instead of just one Slide the movable jaw onto the bar to check the fit if you put a little pressure on the Jaws the movable jaw should lock into place you also might want to turn the clamp vertical like this and let this down slowly hear that chatter that's a good fit if the fit is too tight reach into the mortise with a small file and file one or both of the Roll pins until the action loosens up if the action is to lose the clamp may not hold when you throw the cam lever if this is the case drive one of the pins out of its hole re-drill the hole to a slightly larger diameter in this case five thirty seconds of an inch and then drive a 5 32nd of an inch roll pin into the enlarged hole there's one more thing that you may want to add to your clamps because the finger of the movable jaw bends when you throw the cam the jaw faces will be slightly misaligned to compensate buy yourself a small rubber pad these are available in the plumbing section of most hardware stores cut the pad into pieces to cover the jaw faces then stick them to the faces with a Shoe Goo a really tenacious type of rubber cement and that's it nothing left to do except find something to clamp and this being a woodworking shop that shouldn't be too hard thanks for your kind attention [Music]

Channel: Workshop Companion

Views: 92,171

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Id: S_W6gWv6g_I

Length: 17min 9sec (1029 seconds)

Published: Thu May 04 2023