LenVW said:For more information, please visit DRAKE.
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How did you check your spindle with a dowel pin without a chuck or a collet?Or did you mean you checked the stacked spindle runout with a chuck or collet and a pin? @van123d - you will find that many folks on here have agreed to disagree on Accusize. I'm one of those who likes them. I've bought lots of stuff from them that I'm very happy with.I usually buy accusize from Amazon for the free shipping and free returns and convenience. But like others have said, if you are not happy with whatever you get you can either return and exchange with Amazon, or call Accusize direct. They have ALWAYS made me happy - even when the problem was my fault.I will almost always choose Accusize over Ali even if I think there is good reason to believe it's the same stuff. My quality of life is better paying the extra to get it in two days with no worries about returns.Which chuck did you get? Looking forward to seeing your review of it.My experience with chuck runout is kinda weird. I have a Gerardi Spa chuck that came with my used milll - not quite the reputation of Albrecht, but up there. I was shocked at its runout which I thought wasn't that good till I started seeing the runout of other members chucks. Now I think it's pretty darn good - big attitude adjustment for me.If you have an R8 ER collet system, and you need better runout, you might consider drilling with that instead. If you don't have that, I'd consider getting one....... from Accusize LOL. I think ER32 is the most popular in the R8 spindle class but I'd easily be convinced otherwise.
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Tolerance contributions prevent mass-produced drill chucks from achieving a higher standard of accuracy. Consider the way that most drill chucks are assembled: the rear body of the chuck is either threaded or taper-reamed to accept an arbor. The arbor is threaded or tapered to mate with the chuck. The shank of the arbor is configured for different machine tool applications, both straight and tapered. (The shank configuration depends on the machine to which the drill chuck is fitted.)There are four critical interface configurations to get "right" and the inexpensive products function as well as one might expect for the price. But it is possible to improve performance - as much as a factor of three to five with some imported chucks. The following is a description of a procedure I've used for some time - it has worked well for my personal precision drilling requirements. Note that this process is mainly intended for hobby machinists because they usually have available time and because there are several useful lessons involved.This reads like a complicated process but implementation time of the procedure will be about two hours or less. Of course it is difficult to translate these ideas verbally - worse in written form - apologies if the explanation is unclear. I'll slip in a photo or two from time to time &#; hopefully clarifying the explanations. (We'll assume that your lathe is leveled, aligned, spindle bearings tight, no excessive wear - all the normal precautions. Experienced machinists can work around deficiencies in many of these areas but the rest of us should not assume that we can.)Let's also make the presumption that the internal chuck mechanism has no inaccuracy. This can be justified because the average home machinist hasn't the capability to improve the basic internal design so we may as well ignore it. More importantly the greatest sources of error are external to the drill chuck mechanism.The greatest error contributor is the arbor, mass produced to fit other mass-produced parts. Either of the two interfaces, arbor to chuck or arbor to spindle, introduces angular, concentricity, dimensional and axial errors. I'll describe the following techniques as if we were accurizing a lathe tailstock chuck and remember that an additional presumption is that the lathe used to perform this work is properly set up as noted above.The simple premise is that we will chuck and turn a steel pin in your lathe so that it is as concentric with the spindle axis as we can normally produce. Without removing the pin, we will then tighten the jaws of the chuck we want to true on the pin. After performing some preliminary and intermediate measurements and adjustments, we'll turn the attached arbor shank concentric to the spindle with the correct taper dimensions to fit the lathe tailstock.Before commencing it's necessary to purchase or make a blank arbor for the desired drill chuck. The arbor must mate securely with the drill chuck and have a shank diameter greater than that required for the eventual end use (if used in a Morse taper tailstock, the diameter must be greater than the maximum diameter of the tapered tailstock socket with a little excess diameter and length). If purchased, the blank arbor must be machinable (not hardened beyond around Rc-40 or so, softer if HSS tooling is to be used).(NOTE: I had a useless chuck with 2 MT shank with excessive runout. I wanted to use the chuck and it was convenient for making the photographs but it isn't exactly like this procedure describes, please keep that in mind. I'll point this out later when it seems appropriate.)The next step is to select (or obtain) a tailstock tool that has a taper well-fitted to the taper in your tailstock. This is important because it will become the "reference" for a critical part of the procedure. Most of us have several Morse taper centers and several Morse taper drill chucks for the tailstock, so we can sort through them and select the best one. (FWIW, all of the drill chucks shown were trued using this technique.)After thoroughly cleaning the tailstock socket, pick the tool with the taper that best fits your tailstock socket. This is usually determined by bluing the taper on the tool, inserting in the tailstock socket and lightly rotating the seated tool. Inspecting the various tools, the one with the greatest area of contact (most bluing wiped off) is the tool best fitting your tailstock socket. In my case, this happened to be an after-market dead center, so I'll use that part and that taper to illustrate the following steps.The most finicky part of this process is aligning the compound rest to replicate the taper of the tailstock (assumes that a taper attachment is not normally available to the hobbyist). Although this seems obvious, first confirm that the compound travel on your lathe is adequate to turn the full length of the tailstock Morse taper. (Traditional lathes, European and American-made, always had this capability but it's possible that some inexpensive Asian imports do not.)Commence the process by moving the tailstock near the headstock. Place a DTI in the headstock workholder (chuck or collet, whichever is convenient), lock the tailstock to the ways and carefully sweep the tailstock socket for concentricity with the lathe spindle (use a small mirror to observe the DTI when it is out of view). Align the tailstock if necessary then install a drill chuck with center drill in the socket. Now sweep the center drill body with the DTI and, if it is not coaxial with the spindle, shim it until it is coaxial and level.(When working with machinery, please note that a good selection of shim stock is very useful. Rolls of stock are available in different thicknesses from distributors like "Enco" and normal household products - soft-drink cans, canned food containers, even aluminum foil - are a source of various shim thicknesses. I find shims so useful that I have several drawers in my tooling cabinets reserved for them.)(A useful habit to develop is to "load" moveable parts of metalworking machinery the same way each time movement is required. We know to take up backlash in lathe and milling machine handwheels and the same concept is universal, if we want to achieve consistent results (especially on older machines). If there is any play, any movement between parts, be sure to take up the movement in the same direction every time - as in moving the tailstock from one position to another position, always pushing it against the same side of the ways.Chuck a steel rod in the lathe headstock securely (= tight !). The diameter should be greater than the maximum capacity of the chuck to be "accurized" (3/4 inch is a good selection for small chucks) and the length protruding from the chuck (or collet) should be slightly longer than the jaw engagement length of the chuck when it is opened to 3/4 of the jaw capacity.Lightly face the end of the steel rod (to prevent the center drill from wandering) and then carefully center drill the piece. Turn the steel rod in the headstock to a diameter approximately 3/4 of the maximum capacity of the drill chuck to be accurized. The length of the turned diameter should be slightly LESS than the length capacity of the drill chuck. Measure the diameter of the workpiece at each end to confirm that there is no taper, correct as required until the "pin" is straight.Using an indelible marker or a scribe, mark the drill chuck arbor and the tailstock ram so that the drill chuck/center drill can be removed and re-installed in the tailstock while remaining aligned with the spindle centerline. Do not remove the center drill from the drill chuck until this procedure is complete. In fact, it is good practice, once the center drill is well adjusted, to leave it permanently in the chuck to which it is aligned for all center drilling applications. (My personal opinion is that at least three chucks are required for the lathe and also for the milling machine. A large 5/8 inch capacity chuck, a 1/2 inch capacity keyless chuck and a 1/4 inch chuck with center drill or spotting drill, for the vertical mill.)Remove the drill chuck from the tailstock and replace it with a known good center. Locate the "reference center" between the previously center drilled hole in the 3/4 steel rod and the tailstock center. (Use the factory center of the reference dead center. It was previously used to grind the taper and is, by definition, concentric.)Loosen the compound locking nuts and rotate so that it is approximately parallel to the taper of the reference center. As shown above, install a DTI in the tool post (or use a magnetic base) and adjust the tip of the DTI precisely on the centerline of the reference center. Lock the lathe carriage and traverse the compound slide while observing the DTI.Make fine adjustments to the angle of the compound until the reference center can be swept over full length with no detectable error. The compound axis is now parallel with the Morse taper of the reference center within the limits of the DTI. Unlock the tailstock and back it away, removing the reference center. The reference center will not be required for the remainder of the process.Slip the "to be accurized" drill chuck with arbor installed over the reference diameter previously turned from the 3/4 diameter steel rod in the headstock chuck) and snug the jaws.Rotating the drill chuck by hand over the reference diameter, tighten the chuck wrench gradually until the chuck is completely secure. Replace the tailstock chuck + center drill in the tailstock, using the alignment marks that were established before removing the chuck earlier. Carefully center drill the end of the blank arbor then remove the drill chuck from the tailstock.Install a "known good" tailstock center and adjust it to apply moderate pressure to the center drilled hole in the drill chuck arbor.OK, let's understand what we have accomplished so far. We've established a reference "pin" in the headstock that is turned concentric to the lathe spindle. We've securely installed the chuck to be "accurized" on the reference pin and accurately established a center at the end of the blank, "rough" arbor.The drill chuck jaws are now aligned with the spindle axis and the center on the end of the arbor is on the lathe spindle center line. At this point, it is unlikely (actually, impossible) that the blank arbor is concentric with the spindle or parallel with the spindle center line and we are now going to correct those conditions.We've adjusted the angle of the compound as close as we can establish to the tailstock taper. All that remains is to taper the drill chuck arbor to the desired angle and finish diameter. Sounds simple but there may be a hiccup or two in store for us.(I mentioned earlier that these photos don't depict a drill chuck with a blank arbor installed - the original process assumption. These photographs depict an old chuck with #2 Morse taper, unused because of excess runout > .006 TIR &#; note the rust resulting from disuse and lack of care. In order to true the arbor, it was obviously necessary to reduce the diameter past the point where the arbor would properly fit the tailstock socket. The diameter needed to be reduced - at least - by the amount of runout error. Practical considerations made the actual diameter reduction even more - the major diameter of the original arbor was actually undersize as shipped from the distributor! I made a shim to correct for the undersize arbor but the runout was too great for my needs so the chuck and arbor were - more or less - discarded.)I decided to modify the drill chuck to fit my vertical mill by fitting to an R-8 arbor (with 2 MT bore) that I already owned and wasn't using. After truing the drill chuck arbor taper, the smaller diameter taper couldn't fit this arbor, just as it would not fit the lathe tailstock socket. BUT the R-8 holder can be modified to accommodate the smaller taper on the drill chuck - clearly modifying the tailstock ram wasn't under consideration. We'll get to the R-8 modification shortly.We want to minimize cutting tool overhang, especially for small lathes that aren't very rigid. In this setup configuration, the compound slide handwheel has to be as close as possible to the headstock - without interference. Adjusting the cross-slide, so that the compound can obtain full travel without "bumping" the headstock with the handwheel, is the optimum configuration. Even so, it will be apparent that the lathe tool post is further from the workpiece (the drill chuck arbor) than we desire.Improvisation may be required to locate the cutting tool close to the workpiece with sufficient rigidity to turn the taper on the blank arbor. I've used several makeshift setups to achieve workable solutions using light cuts. The simplest one, in my machine, is to use a boring bar for a turning tool. In the following photo the shop-made boring bar is turning the taper.Another practical expediency is to support the end of the cutting tool with a machinist's jack as in this photo of a different setup. Note the "vee" groove in the top of the vise - very convenient for supporting round objects like this boring bar holder.Cut the taper on the blank arbor until the desired fit is obtained. This can be determined by measuring the major diameter and - when the diameter is near size - checking the fit as follows: unlock and back off the tailstock, remove the center and slide the tailstock over the arbor and check for fit by bluing and rotating the arbor in the tailstock.Once the desired fit has been obtained, sand/steel-wool the arbor to a clean, smooth surface. In the following photo, an existing, hardened arbor has been re-trued. A C6 carbide boring tool was used with a fast spindle speed to obtain a nice finish - no supplemental polishing was required. As a matter of interest, it's often possible to achieve better finishes on hard material with carbide tooling than on softer materials, like cold-rolled steel or even aluminum. (Note that a good finish is necessary so that the taper "locks-up" by friction with the mating part.)We know that the modified taper is too small for 2 MT dimensions in the R-8 arbor. In order for the two parts to properly mate, the face of the R-8 arbor must be cut back until the socket diameter matches the large diameter of the drill chuck shank. In large lathes, this is a simple operation, chuck the R-8 workholder and face the front surface with a carbide cutting tool. My small Emco 8 x 18 doesn't have a large spindle bore so the operation was slightly more time consuming. Here's a photo, the end of the R-8 arbor is held in the 3-jaw headstock chuck of the lathe, supported at the front with a steel shop-made steady rest (note that the tips of the bearing surfaces have been "tinned" with bronze brazing rod, for a good bearing surgace). The same carbide boring tool was used for facing, since it was already in the setup.For truing drill chucks with straight shanks used in some milling machine collets, the procedure is simpler. No taper need be turned on the arbor although the tailstock center should still be used for control (minimum tapering of the shank. There are a few things to consider when making milling machine drill chuck arbors. A shank diameter of around 5/8 or 3/4 is desirable for reasons of accuracy and wear. However one might also want to consider time expended in making tool changes.Most of my work involves making small parts and large R-8 collets get infrequent usage. I use two drill chucks; one is 5/8 capacity with an R-8 arbor with .003 runout when purchased. That's OK for "Silver and Deming" type drills, for example, where maximum metal removal is the goal, not precision. Straight shank drill chucks can't handle heavy feeds required by these large drills - they will slip in a collet, possibly damaging both the arbor and the workholder. (It's best to have both types on hand.)For greater precision (location and diameter), a smaller chuck was accurized using the previous procedure. A straight shank diameter of 1/2 inch was chosen for the arbor. The reason for selecting this diameter was because most of my milling operations require a 1/2 inch collet; no collet change is required when switching from end mill to drill chuck. If one uses a manual machine, it's easier to insert a drill chuck with straight shank into a collet rather than cranking the knee down several inches to install the long R-8 mounted chuck, then cranking it back up again to working height. Here's a drill chuck with shank being trued to straight 1/2 diameter:One drawback previously mentioned is that the arbor material must be no harder than what can be readily worked by C6 carbide tooling. This suggests that one might expect occasional "dings" on an unhardened arbor. This should not a problem provided that you are aware of the possibility. Make it routine practice to quickly run the taper through your fingers, feeling for irregularities before installing into tailstock or spindle. (If/when found, stone irregularities flush with the original surface.)Of the four chucks in current use that have been trued with this procedure and measured after truing, all displayed less than . runout, one inch away from the chuck jaws. The measurement was made by indicating a ground pin, diameter approximately 1/2 the maximum chuck capacity, secured in the chuck jaws. (Years of wear on the mechanism have doubtless degraded performance.)One final suggestion &#; before the compound angle is disturbed, make up three or four blanks with the appropriate tailstock taper. Buy a MT adaptor that has an OD to fit your headstock taper and ID to fit the tailstock taper. By installing your tailstock taper blanks into the adaptor and installing the adaptor in the headstock taper, special tailstock tooling can be made up when required without having to repeat the compound angular alignment. (Depending upon operations performed, it may be necessary to tap the small end of the taper for a temporary drawbar, to hold the workpiece securely for machining.)Hope this has been helpful,RandyEDITED to add:For precision drilling, take advantage of the increased rigidity of screw-machine drills. They are short, robust and frequently do not require spot drilling or center drilling - helpful when one is making more than a few parts.Also helpful when one requires close tolerance holes that are aligned with the machine spindle is the following procedure:1. spot drill and drill undersize2. use an end mill, feeding s-l-o-w-l-y to produce a round hole that is truly aligned with the spindle3. finish drill to near size (drill will follow the diameter that the end mill bored)4. ream to finish size
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