* GadgetBuilder.com *
Click to Enlarge
Sharp drill bits are helpful in getting the best from the minilathe as well as the drill press, mill-drill, and even a hand drill. For drill bit sharpening in the home shop, Pit Bull type inexpensive sharpeners can do a surprisingly good job on twist drill bits from 1/2" down to about 1/8" or slightly larger. Smaller drills are not handled by this sharpener so another approach is needed. Ian Bradley's HoneDrill fixture can be built to sharpen small drills, facet larger drills, and hone some other cutters as well. Derek Brown's four facet drill sharpener is easier to build and quickly sharpens small drills very well; both are described below, as is using the inexpensive sharpener for larger drills.
My interest in building a drill sharpening jig arose from reading that four facet drill geometry improves overall drill performance. Four facet geometry: reduces wander at startup, needs less pressure for drilling, generates less heat, and wears more slowly. I had noted that center drills can wander at start of drilling: their short, stiff nature isn't really a solution so much as a way around most of the problem. My original goal was to produce center drills with four facets to reduce wander at startup -- the ability to sharpen all small drills was a fringe benefit which happened to come along with the sharpener for center drills.
My understanding of drill point geometry and drill sharpening improved considerably from reading the article referenced below and especially from using the HoneDrill fixture. Adjusting and using this fixture is almost a mini-tutorial on drills and their geometry. Plus, it allows experimenting with relief angles, easily allowing four facet sharpening of drills, for example. Derek Brown's sharpener is much easier to build and use but doesn't illustrate drill geometry variables as well since they are fixed during construction.
This article on drill point geometry suggests conical drill sharpening is easy to do but conical drills don't perform as well as faceted drills and that most drills sold in the US have excessive relief. The pictures are interesting and show some advanced geometries that are not often found in the typical home shop. However, reduced relief for larger drills can easily be provided by adjusting the inexpensive sharpener differently than suggested in the directions or by adding a primary facet with the HoneDrill. Small drills can be ground at any desired relief angle(s) using the HoneDrill fixture and four facets can easily be produced if the user desires. Derek Brown's four facet sharpener produces fixed relief angles of 10 and 25 degrees although the fixture is easily modified to produce any two selected relief angles - however, once selected they are fixed forever. Reduced relief is helpful in reducing chatter and hogging in, often a problem when using inexpensive drill presses because the minimum speed is higher than desirable for many drilling tasks.
My approach to achieving sharp drills evolved as I went along (learning about drill geometry and building sharpeners). Initially, I expected to sharpen all drills in one fixture but found it easier to get good results by using several fixtures to cover the range. Present strategy is to use the Pit Bull conical sharpener on larger drills, then add a primary facet with the HoneDrill. For medium size drills (0.25" to 0.1") I made a square pin vise and collets per Derek Brown's article for a scaled up Four Facet sharpener; this is used with the HoneDrill fixture and the Pit Bull since I have those fixtures already (info on even larger collets of this design is found about half way down this page). For small drills (#42 to #80) the Four Facet Sharpener does a great job.
Building and using the Four Facet and HoneDrill sharpeners along with the Pit Bull provides a practical education in drill sharpening. The HoneDrill in particular is educational and also thought provoking. The combination of the Pit Bull plus Derek Brown's collets is reminiscent of a Champ Sharpener's dual bed. An adaptation of the HoneDrill concept combined with these collets (including sizes to handle 1/2" drills) plus a small electric grinder would allow sharpening drills with the 4 or 6 facet technique more easily than by hand - split point might also be possible. In fact, I suspect there is a commercially viable product lurking within these simple ideas, as suggested in the HoneDrill description. NOTE: Since building the Brooks cutter grinder I've added a HoneDrill inspired jig to it for sharpening larger drills.
Click to Enlarge
Derek Brown's article describing his Four Facet Sharpener for small drills (#42-#80) appeared in "Model Engineer" for January/February 1993; the article was updated and reprinted in the same magazine in May 2000. A version for drills to 1/4" appeared in "Model Engineer" for August 1996. Derek was kind enough to supply copies of all these articles when I couldn't find construction info on the net. My interest originated from a variant of Derek's unit shown on Alan Marshall's site. This Four Facet Sharpener works very well for small drills; for those who would like to build one and can't find Derek's articles I have tried to provide enough info here to allow construction.
The clever thing about the pin vise for the Four Facet Sharpener is that it is rectangular. This makes it easy to get both sides of a drill aligned the same: simply flip the vise over. The vise works in the HoneDrill fixture too although the nut prevents it from registering properly on the back end; this can be compensated by adjusting the fence but I made a longer version of the pin vise so these nifty collets can be used easily in both fixtures.
The article indicates that slitting the collets is the trickiest part of building the unit so I made the collets first - if I couldn't make the collets there would be no need for the tool block. The collets are made from 5/32 drill rod where 4 collets will accommodate drills from #42 through #80. I used a 5C spin indexer to hold the collet blanks for slitting but since I didn't have a 5/32 collet I used a 3/16 split sleeve to hold the 5/32 blank in a 3/16 5C collet. Confusing to describe but it worked well. I stopped the mill to take this picture of the process. The saw is a Thurston 0.015 thick blade, close to the 0.016 blade specified in the article. The collet blanks are 5/32 drill rod, 1.30 long where the body is drilled out with a #42 drill except the last 3/16 which is drilled to size the collet. The drill sizes specified for this are: 42, 49, 55 and 68 -- I didn't make the smallest collet (yet). The end of the collet blanks are tapered at 15 degrees and a 15 degree reamer is made from the same drill rod to form the taper in the body of the pin vise. The vise body is 1.5" long by 0.250 by 0.220, drilled out to 3/32 then enlarged to #22 = 0.157 except the last 1/8 which is reamed with the 15 degree reamer leaving about 1/32 un-reamed; I put the reamer in the lathe chuck at low speed and pushed the vise body onto it by hand, cleaning chips out and checking progress frequently. A 9/16 long brass nut threaded 10-32, also through drilled 3/32 completes the pin vise. I added grooves at the rear of the collets to indicate the size. This collet and pin vise work really well, little force is needed to solidly lock a drill in place. The collets expand slightly when slit so they must be removed from the pin vise by pushing them with a small drill.
Machining these tiny collets is fussy work; some details concerning this: I made a split sleeve by end drilling a 12 inch by 3/16" brass rod about 5/8" deep, then adding 4 slots with the 0.015 saw. The rod was run through the 5C collet and extended out the other end of the spin indexer. A drill chuck was clamped on this end and used as a handle to move the split sleeve in and out while inserting and removing collets. Slitting was done by approaching from the side of the collet blank with the saw set to clear the 5C collet by about 1/16". The collet blank extends 1+ inch from the 5C so it is gripped by about 1/4" of its length -- this allows slitting about 15/16" of the collet length. My saw blade is small diameter so the end of the collet conflicts with the saw arbor; this forces completing the slit by rotating 180 and coming in again. When slitting, a curl of metal comes out of the side away from the blade and this occurs inside the collet too. This swarf should be removed in place as best as it can be after each cut else the blade will re-cut this swarf and could jam and break. After cleanout, rotate 180 degrees and complete the remaining part of the slit on the other side, clean swarf again, rotate 90 degrees and make the other slots, cleaning after each cut. On completion, the collet will be full of swarf and have burrs so run the #42 drill in by hand as needed to clean things out. In addition, the exterior of the slots will have a burr along the length which must be removed before the collet will fit into the chuck. It takes about as long to clean and debur a collet after slitting as it does to slit it. The collets need not be hardened.
I made the main tool block from scrap aluminum rather than (1x1.5x2) steel as called for in the article (if it wears rapidly I'll make one from steel or HDPE). The article recommends angles of 10 and 25 degrees for the sides; these angles set the relief angles for the facets. Opinions vary on appropriate relief angles, where other sources recommend 6 and 20 degrees so I split the difference and used 8 and 20 degrees. I squared up the stock and scribed lines showing the angles on the end, then used these lines and a parallel laid on the top of the vise to align the part to the vise top and milled the angles into the block. The vise was rotated 59 degrees so the slots for the pin vise could be milled into the angled sides. Each side in turn was set even with the top of the vise and a 1/4" wide by 0.220 deep slot milled so it went through the geometric center of the side - this picture shows a slot being cut. The slot at 59 degrees is appropriate for a 118 degree drill, the angle found on most twist drills. To handle a variety of angles the HoneDrill fixture is more appropriate; the Four Facet Sharpener is simpler and faster to use but less flexible in the tasks it can handle. This shows the end and side views; note the slot for the pin vise goes from upper right to lower left - this is true for both slots in a block.
To complete the unit I added black Delrin side plates using 6-32x1/2 flathead screws. The pin vise should be a shake free fit in the slots so make any minor adjustments needed to achieve this. The vise is rectangular to ensure it only fits in the correct orientations; I left the vise square until the side plates were added, then trimmed the vise with the fly cutter and made final adjustments on the bench sander. Chamfer the corners of the vise so they don't interfere with the fitting process.
The plans call for the block to run on rails using a diamond plate for sharpening. Instead, I used sealed ball bearings (salvaged from discarded VCR's) as wheels with 6-32x1/2 button head screws as axles. I use #600 carbide paper laid on a granite block for sharpening, where the wheels hold the sharpener body about 1/16" from the paper. The nose of the pin vise is fettled by placing a small piece of cereal box cardboard on the bottom of the tool block for protection, then filing the tip of the vise in place to within 1/32 of the hole -- do this for all possible orientations/positions.
This sharpener is much simpler to use than the HoneDrill and does a fine job sharpening small drills. It takes some experience to judge how many strokes and what stroke length to use vs the condition of the drill. 600 grit carbide paper cuts rapidly, at least when its new: about 6 strokes 4" long is enough to put a 20 degree (secondary) facet on a #50 drill and 1 or 2 much shorter strokes adds the primary facet. If a drill is damaged or the chisel is off-center and must be corrected then it would take longer than the 2 minutes it takes for a drill which is only dull. It can take longer to put the drill in the collet and align the flutes vertically than it does to sharpen it (but see the alignment gadget below). Centering the chisel is a judgement call where a couple strokes on the shorter side generally does the trick. Re-sharpening a four faceted drill is nearly instant if the drill is only dull - one or two strokes on each facet.
User Note: The article specifies a diamond plate for sharpening and I found part of the reason: grit from stones or carbide paper sticks to the end of the drill bit and can drop off inside the slot which holds the pin vise, making it difficult to re-insert the vise. My solution is to pick the block up and wipe the drill point with a paper towel before withdrawing the pin vise. I tried using this fixture on an oilstone before I figured this out - the oilstone made the problem obvious although it works well when reworking damaged drills needing more than simple sharpening. To clean the slots push a wad of paper towel through; as with most grinder fixtures, never clean with liquid or apply oil because grinding dust will stick to it and cause trouble.
An optical aid to accurately align the flutes vertically is helpful for the tiny drills sharpened in this fixture. The magnifier in this fixture incorporates a line to help judge when the flutes are vertical. This is calibrated by rotating the (friction fit) Lucite lens to align the fiducial line with the side of the rectangular pin vise. The lens design is similar to the optical center punch lens but shorter; the outside surface is spherical while the side toward the drill is flat and has the line -- the focus is about 1/8" from the lens, magnification is about 4. Magnification and distortion increase as the drill is moved away from the lens. The pin vise is held into the corner of the fixture to center the drill in the magnifier.
To keep track of the tiny collets I drilled storage holes in the top of the main block. Friction holds the collets in these holes and the ID rings allow picking the correct one.
I expect that if the main tool block were made 1/2" longer it would accommodate a second slot for the 1/2" pin vise used for drills up to 1/4". Alternatively, 1/2" by 0.475 slots could be made in a slightly larger main block and the small pin vise described above could be made from 1/2" stock instead of 1/4" stock; this would allow this pin vise and the larger pin vise described below to fit the same main block. Unfortunately, I thought of both of these approaches after I built the small block so I'll use the 1/2" pin vise with the HoneDrill instead.
Click to Enlarge
Ian Bradley's HoneDrill fixture looked to be flexible enough to allow a little experimenting with drill geometry and seemed easy to build. In use the bit's lip is held vertical by the triangular block and this block is then pivoted about the lip to set the relief angle. The fence can pivot to accommodate slight differences in point angle (118 is standard). While conceptually simple, it illustrates drill geometry and how drills work very clearly. I eventually built what amounts to a motorized HoneDrill to handle larger drills.
SPECULATION: This picture of the HoneDrill next to the Brooks jig implies that mounting that jig to an angle plate so the axis of the round is parallel to the side of the bench grinder wheel (with a facility to allow rotate & lock on that axis) plus adding a screw driven axial infeed (attached to the stop rod) combined with a guide to allow sliding the contraption parallel to the side of a bench grinder wheel would provide a very capable gadget for 4 or 6 facet sharpening of drills from 3/16" (or less with a pin vise) to 1".
I purchased the raw material that I didn't have on hand at a local machine shop for $2 and away I went. 
It turns out that, as usual, I didn't estimate the work involved very well. Ian Bradley suggested that the triangular block could be shaped by hand with a file but that the top surface should be machined to obtain a good fit with the V block. I assumed that my milling machine would make the job much easier but it turned out not to be as easy as that. With a file you just work away at any desired angle to shape a part but with a mill it takes another setup for each facet on the part and there are a LOT of facets on the triangular main block and on the parts that make up the fence. Even the little "V" block needed several setups; an angle vise would simplify the setups considerably.
The clamp for the V block was a challenge. I marked it out, milled the inside to the lines (a coordination exercise on the mill handles), then used a Woodruff cutter to finish the feet that engage the slots in the V block. The clamp's top was milled at 45 degrees on each side and then I cheated and used a file to complete it.
The movable part of my fence is HMWP, a plastic nearly as slippery and abrasion resistant as Teflon - it remains to be seen how well it holds up in practice with an abrasive stone rubbing on it; so far it seems OK.
I made a few minor changes. I used only two screws to secure the quadrant to the fence and one of the screws holds the hinge pin. Rather than Allen screws I used flathead screws to secure the fence and main block to the base. The drawing calls for a single bolt in the center to lock the main quadrant but the picture shows two holes; I followed the picture. All of the adjusting screws were turned from brass and knurled. As noted, the movable part of the fence is from HMWP, where the article suggested Tufnol or hardened steel. The fixed part of the fence is aluminum. (I believe there is an error in the drawing in that the quadrant for the fence doesn't fit properly if built per the drawing.) The base is "mystery metal" from the dump; it is a type of stainless that is apparently a close relative of Kyrptonite - it took 40 minutes in the bandsaw for one cut 1/4 inch thick by 5 inches long!
If I were to build it again I would make the bottom quadrant long enough to go the length and include the hole for the pivot bolt, then bolt the main block (59 degree angle), shortened slightly, to it - seems like it would be easier to machine that way. The quadrant for the fence should be on the right, at least for right handed users (I changed it since taking the pictures). It would be useful if this quadrant allowed more inclination away from the main block (an easy mod); this would make it easier to hone the end teeth on slot drills with a narrow India stone.
To simplify setup I made punch marks on the base at 0 and +/- 10 and +/- 20 degrees of relief setover, then filed an alignment mark on the rear of the main quadrant, as seen in the pictures.
The first drill I sharpened was the #2 center drill shown in the picture at the top of this page. This drill was fairly new so it was quick and easy to four facet it. It now starts without wander but drilling pressure is only slightly reduced.
I used the HoneDrill to sharpen a very worn split point "F" drill using four facets - not commonly done but it seemed like an interesting thing to try. The result is different looking, as seen in the picture. This was done with a carbide stone. I tried an aluminum oxide stone but it quickly became grooved. I will also try carbide paper glued to a wood backing - I expect fine carbide paper will produce a better surface finish on drills. It took 20 minutes to hand sharpen this relatively large and badly worn drill - it would likely be better to sharpen drills larger than 1/8" with the Pit Bull sharpener and then add a primary facet with reduced relief since this should be quick and easy.
As an experiment I used the HoneDrill to add "Secondary Point Angles" as shown in Figure 4 of the article on drill point geometry. Although it is easily done, it felt like I was ruining the drill because it was such an unusual thing to do. In fact, the section ground away is in the area that I have seen chip on a number of (abused) drills. The 1/4" drill I experimented on cuts steel nicely but it is impossible to evaluate whether all the claimed benefits are actually realized without conducting a controlled experiment. However, it is easy to do and works well enough that I will add SPA facets to some drill bits I commonly use and see how it works out.
I had read about adjusting drills for use on brass and plastic but didn't understand how to do it accurately. The HoneDrill does this nicely, just set the relief angle to zero or 1 degree and add a primary facet; the low angle reduces self-feeding, the cause of grabbing in brass and similar material. I have a set of inexpensive drills from a Homier sale which are dedicated to brass and will be adjusted as needed in this manner. Some material will grab even with a low relief angle; if this happens the rake can be adjusted with a slipstone, making a very narrow facet parallel to the drill axis on the front of the cutting lips. Note that four facet drills cut well in steel but tend to grab in brass because they do cut so well.
The HoneDrill can sharpen things other than twist drills. End mills sometimes chip on the end of a flute and one way to continue using them is to make a small facet at 30 to 45 degrees on the end of the flute (similar to the SPA on drills noted above). The result won't cut sharp 90 degree corners but apparently lasts considerably longer than an acute corner so this is sometimes done deliberately during sharpening. On the HoneDrill, put the endmill in the V block with the flute vertical, put the fence forward as needed, set the relief angle to 6-8 degrees and hone to produce a facet. Make identical size facets on the end of all flutes.
"D" bits can be sharpened or even produced in the fixture. Generally, it takes a while to remove much metal by hand with a stone so where possible rough the shape on a bench sander or grinder first then finish to the desired angles in the HoneDrill.
The HoneDrill plans call for a pin vise with locating pins to index small drills for sharpening. After seeing the pin vise and collets for the Four Facet Sharpener and reading Derek Brown's article "Four Facet Sharpening: Extending the Range", Model Engineer August 1996, with scaled up collets I decided to use his approach rather than the one suggested in the HoneDrill plans. Three collets handle the range from about 0.085 through 0.250; 180 degree indexing is inherent in this design.
This larger pin vise is analogous to the small pin vise described above except it is made from 1/2" stock 2.5" long. The larger collets are considerably different in design, being slit on both ends so they can collapse onto and accurately position larger drills. These collets have a taper on both ends and the pin vise includes a tapered brass piece on the upper end so both ends collapse simultaneously as the knurled nut is tightened.
Construction techniques are similar to the small vise and collets in many ways. The vise body is drilled 3/8" except the last 3/8" which is drilled 1/4" and reamed with a 15 degree reamer made from 3/8 drill rod as a tapered D bit - same technique as the small collets. The last 1/16" is not reamed, remaining 1/4".
The 3 collet blanks are 3/8" drill rod 2.188" long, tapered 15 degrees (i.e. compound setover is 15 degrees) on each end to 1/4" diameter. The collet blanks are drilled to 1/8", 3/16", and 1/4" respectively. Each collet has 4 slits on each end, where the 1/16" slits are interleaved by rotating the blank by 45 degrees when it is reversed to slit the second end. I held the blanks in the spin indexer where about 1/4" beyond the taper was needed for a good grip. To set the 45 degree angle a 1/16" thick ruler was inserted through an existing slot to help measure the angle. To allow gripping the slit end of the collet the shank of the drill used previously to bore the collet was inserted just even with the end of the 5C collet holding the blank. The 5C spin indexer works very well in this application, maintaining a sure grip on the collets as they are slit. Slitting to within 1/16" of the 5C was easily done. Deburring was easier and faster on these larger collets than on the smaller collets from the Four Facet Sharpener. Slitting is not a speedy process when I do it; I spent about 1.5 hours per collet just slitting and deburring.
The brass piece is 5/16" long. It is about 5 thou under 3/8" for 3/32" and the remainder is 5/16". The inside is drilled 1/4" and tapered using the reamer previously used to taper the pin vise, the larger diameter toward the large diameter of the brass piece. As with the small collets, brass on steel has low friction and does not rotate the collet as the nut is tightened.
The knurled steel nut is 3/4" long and up to 5/8" in diameter; I made it 0.460 so it is easy to use with the HoneDrill's V block. The plans call for a 7/16-40 thread; I used a 10x1.25 metric tap and die but single pointed most of the nut's thread on the lathe, finishing with the die. The pin vise was threaded with the tap, going only as far as necessary. Run the 3/8" drill in by hand to gently clean up any metal raised by threading or the collets won't enter easily.
The clamp for the HoneDrill would not allow the 1/2" pin vise through initially. I chamfered two diagonal corners slightly to fit; this has the happy effect of only allowing the vise to fit in two orientations, similar to the constraint imposed by the rectangular shape of the pin vise in the Four Facet Sharpener. Here, the effect is the same but is accidental rather than deliberate - some days you get lucky!
I scribed a fiducial mark across the face of the pin vise between the chamfered corners. This is adequate for aligning by eye the flutes of all bits in the covered range. An optical aid, similar to that built for the Four Facet Sharpener, proved unnecessary so I have an extra Lucite lens awaiting some future project -- a peril of mass production to avoid extra setups.
This pin vise fits into the Pit Bull sharpener as well as the HoneDrill. Chipped or damaged drills can be refigured quickly in the Pit Bull, then transferred to the HoneDrill for faceting. Proper indexing isn't enforced by the Pit Bull holder so you must stay alert to rotate the vise by 180 degrees. Also, when removing considerable material from a drill it may be necessary to adjust the drill bit in the vise to maintain the desired orientation of the flutes to the vise.
The inexpensive Pit Bull type commercial sharpener (sold under many names) is adapted from a 1913 design by L.A. Van Royen which was refined slightly by Duplex in 1963. This sharpener produces a conical point and is adjustable to handle several common point angles as well as various relief angles.
I read on the net (can't recall where) that the grind marks on drills should be perpendicular to the cutting lip. This because grind marks parallel to the cutting lip encourage bending at a grind mark near the lip resulting in fatigue failure which shows up as missing sections of the lip. I had set my Pit Bull up per the pictures in Duplex's article which show the bit touching at 9 o'clock on the wheel; this results in grind marks parallel to the lip. I examined some drills I had sharpened and found rectangular chips in the cutting edge, as shown in the picture. I checked some good quality new drills and found the grind marks were perpendicular to the edge and much finer than the marks on drills I sharpened.
I revised my Pit Bull sharpener setup as shown above. My ancient Baldor has a large nut on the shaft, so large that it prevents the Pit Bull from reaching the wheel if it is mounted so the drill bit would touch at 12 o'clock. So, it is set up to touch at about 10:30 on the 6" wheel. This compromise doesn't yield grind marks perpendicular to the lip but they are now far from parallel and the chipping problem no longer occurs. I am at a loss to explain how Duplex and other sources settled on the 9 o'clock position; my experience is that the results are better if the 9 o'clock position is avoided -- YMMV.
In order to raise the Pit Bull from the 9 o'clock contact I added a wooden pad. This is secured on top of the pad for the Tinker using a socket head bolt with a nut embedded in the bottom of the earlier pad. Similarly, a bolt head is wedged into a hole in the bottom of the new pad so a nut can be used to secure the Pit Bull to the pad -- this is loosened to move the unit as required to accommodate different diameter drills.
Using the HoneDrill, a primary facet was added to some drills previously sharpened with the old Pit Bull setup rather than resharpening on the new setup. In some cases it worked out OK, in others there is a bit of a defect remaining. The picture shows a "T" size drill with a small chip at the outside corner; this would likely fail fairly quickly and require sharpening. The obvious solution is to add facets to form "Secondary Point Angles" which removes the chip and should make it less likely to chip again - see the next picture.
The alignment function of the Pit Bull doesn't work well enough to be trusted in my opinion, especially for smaller drills. 
I generally set the lips vertical by eye and results have been acceptable. Grinding a drill, particularly a larger drill, takes a while if it has been chipped or is badly worn. My technique is to repeatedly touch the drill to the wheel briefly, allowing some time for cooling between touches. The contact area is enlarged with each touch until the complete face is ground. Tool steel can tolerate a lot of heat but the lip area is thin, which increases the temperature; better to err on the cool side than to draw the temper.
Overall, the Pit Bull type sharpener is inexpensive and does a reasonable job sharpening larger drills, 1/4" to 1/2". It works from 1/8" to 1/4" but is shakier in that the alignment is more difficult to do accurately so it is possible to have the lips differ -- this results in wander when drilling deep holes; using the larger collets described above solves this problem nicely. Depending on drill condition I use the HoneDrill or, if the drill is beat up, sharpen with the Pit Bull and then add a primary facet with the HoneDrill.
The side of the wheel eventually gets dull and filled with metal particles. A diamond is used to correct this, where I use the Tinker to hold the diamond and move it accurately along the side of the wheel. Very little stone is removed, perhaps 2 thou, taking about 1/2 thou at a time (makes a mess in spite of the small amount removed - cover everything nearby). This doesn't seem like much but it makes a big difference in how the wheel cuts.
Click to Enlarge
I built a copy of Chris Heapy's "Tailstock Sensitive Drill Attachment". It works well for holes within the limit of its 1 inch stroke. The chuck is a Jacobs 1/4" with JT1 taper; the 3/8 rod is small for this taper but seems to work fine so far. The MT2 was made on my taper fixture, of course, as was the JT1. This unit practically begs for a ball handle so I added one but haven't updated the picture yet.
Chris Heapy's site disappeared shortly after I built this unit so the link above goes to the Web.Archive. Here's another archive for Chris's site. In the interim while Chris's site is down, I will send the DXF file I got from Chris's site if you can't get it from the above link - it is helpful to have the dimensions, saves effort thinking and experimenting.
This page was last modified by John Moran, tyro machinist and HTML tweaker. If you would like a copy of the Chris Heapy's DXF, have a comment on my site or its contents or would just like to chat, click here, scroll down and click again.
