The Boring Head 2 Using de Boring Head

let's see how to use the boring head in real life we'll select our boring bar and we'll lock it into place now during our actual demonstration I'm going to be using a longer bar than I would for this thickness of material but that's to allow some clearance so the camera can get a good view of the cutting action when we put the boring bar in we need to make sure that the cutting edge of the boring bar is aligned with the centerline of the spindle that's very important because if it's candid to one side or the other the diameter of the cut is going to be affected and the precision screw will not indicate the amount of movement being cut correctly next we'll gently Snug the jib screws and we want them tight enough not to allow play in the slide but not so tight as to restrict its movement so we're going to adjust them while we move the slide back and forth which will allow us to get it just about perfect and here's our workpiece setup centered and squared away this is a half inch hole that we want to bore out to three quarters of an inch or 0.75 zero we'll set some inside calipers fifty or sixty thousand smaller than the desired finished measurement to use as a sort of quickie gauge it'll let us know when we're getting close to our desired size let's begin by lowering the boring head and moving the tool to the center of the bore we'll open the head up by using an allen wrench in the precision screw and we'll do this until we just feel the cutting bar touching the side of the workpiece at this time we'll slowly turn it by hand to make sure that it's touching but not binding at all this is going to be our starting position now we'll tighten the locking screw once that's secured we're free to raise the spindle and start the milk this is a copy of Machinery's handbook between its covers is a complete engineering course now this is an old copy it's from the 50s but it's still full of more pertinent information than I'll ever be able to utilize new copies can be rather expensive but going online to a used bookstore can net you an older issue for a fraction of its cover price now I got this 1950s 15th edition in very good shape for the princely sum of $10 similar deals come up all the time I suggest that you get a copy the small thumb tab here is entitled speeds feeds now in the next 37 pages of this particular issue is a plethora of tables charts and formula devoted to finding the best speed and rate of feed for your particular operation cutting tool material and shape metal type and hardness size of stock etc etc ad infinitum for our mini machines a lot of this information isn't really going to be practical our smaller mills and lathes won't tolerate the same operational stresses as machines that are made from tons of sturdy cast iron so we tend to base our speeds and feeds on empirical evidence which we gather by making cautious first cuts and proceeding from there now I mentioned before in the animation that vibration can cause serious problems especially when using an unbalanced tool such as the boring head not only can it cause safety concerns but it can also cause inaccuracies watch as we slowly increase the spindle speed not first the mill begins to shudder along the x-axis as we increase the speed even more we'll see the shuttering seemed to stop briefly then resumed but this time along the y-axis as the speed is increased even more the shuttering seems to stop in reality the oscillations are still happening they're just happening faster than we can see the mass of the mill react to them they will still cause flexion between the column and the base which can result in out-of-round bores at the minimum and serious safety hazards at worst so please be cautious and use speeds that will avoid this problem lower the spindles slowly through the workpiece and then slowly raise it back up again this is our first trial cut it gives us our starting point once you've raised the spindle then you can stop the mill now we're going to loosen the locking screw then we're going to dial in our first actual cut now remember a thousandth that's dialed in here is actually mm in bore size so take your time start out with small increments ten or fifteen thousand soar so just to see how your mill the material the speed and the cutting bits are all interacting when you've dialed in your desired cut make sure that you note the setting once you've noted your setting go ahead and tighten the locking screw in preparation for taking the next cut go ahead and make your cut slowly and as smoothly as possible now if you're boring hit starts to chatter don't panic the normal response would be to increase the spindle speed and ease up on the cutting pressure but actually that's just about the opposite of what you need to do instead decrease the spindle speed and gently increase the feed or cutting pressure surprisingly this will usually cut the chatter so to speak of course each situation is different and you'll have to be the judge of what is working and what isn't so just keep a cool level head and keep thinking safety first of course to avoid spring back or flex problems you want to make a second slow pass without changing the setting on the second cut the tool will be able to cut the sides of the board without the pressure of having to remove all that material that was taken out on the first pass this will allow the natural rigidity of the tool to accurately cut the sides of the bore without flexing helping to avoid any taper and giving you a much more true and accurate reflection of the measurement that you dialed in for our next cut let's dial in 20,000th and see how that works now remember 20,000 syn the dial is actually going to cut 40 thousands out of the bore after you've dialed in your desired cut remember to set the locking screw and you can see from the thicker chip being produced that this is a heavier cut heavier cuts are going to put more pressure on the boring bar especially a longest one like the one we're using so our spring back cuts will be even more necessary [Music] moving right along this is a 25,000 Skutt as you can see it's taking a lot of material nearly 50 thousandths of an inch who cuts this deeper possible on some materials and not on other harder materials but on aluminum even 6061-t6 aluminum like this we can still get a nice cut at this depth without changing the setting we'll take a spring back cut with the camera at this angle so you can see how much material is actually being removed on this second pass that's quite a bit isn't it that thin sheet of aluminum that's being peeled back is several thousands of an inch thick [Music] the amount of flex in the boring bar is rather surprising but watch as we take a third cut now again more material is being removed but this time mostly from the bottom of the board as the boring bar removes the last traces of any taper as a remember we set up some insight calipers to act as a gauge to keep us appraised of our progress now that we are telling us we're close to the final size we'll need to get out our telescoping gauges and make very careful measurements on each pass transferring our telescoping gauge measurements over to the one-inch micrometer we find out that we're reading 0.72 six are only 24 thousands under our 7500 target now normally the way I'd cut the remaining twenty four thousandths would be in several passes of smaller and smaller increments sneaking up so to speak in our final measurement to be sure I don't overshoot it but I'd like to demonstrate just how accurate the boring head really is if you take the time to do spring back cuts as we've done and you've measured carefully the boring head will do exactly what you want so for purposes of demonstrating that I've set the cut for a point zero one two which would be the entire twenty four thousands I'll make that cut continue with two spring back passes and complete with a finish pass and we begin we've completed our cut and spring back passes and we're on our final finish pass for finish cuts it's a good idea to engage the fine feed dial and feed the boring bar through as slowly and uniformly as possible the slower and smoother the better the final product and here we are taking our final measurements and the micrometer shows we're right on the money pretty neat huh the boring head is a great little tool once you use it you won't want to live without it

Channel: tavis Garcia

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Id: j3TegunodfQ

Length: 11min 27sec (687 seconds)

Published: Wed Jul 23 2014