| An essential set of tools are for marking out. The surface plate was found in a skip by my father, and had actually been a small surface place. He refaced it and scrapped about 2/3rds of it to a reasonable flatness. The marking gauge is adapted from a design by the late Mr. George Thomas, and is simply a block of steel with a scrapped underside and some means by which a scribe can be set accurately to some pre-determined height. The rule holder is a simple block machined with a groove and some means of tightening the rule which allows a quick swap of ends for metric or imperial measurements. |  |
| Some time ago I was doing a lot of boring, and got through a number of carbide tips for my boring bar. The bar was none too ridged, particularly under load as the edge of the carbibe insert went dull, so I decided to find some other boring bar. Hemingways seemed to offer the ideal solution with their boring tools designed by Dore. These items work rather well as they have a bar held in compression along the whole length of the toolholder. When making the actual tool holders it is best to drill them 3.3mm (tapping size for M4) and use an M4 to provide the compressing force. I tried several times to use the recommended 1/8th inch bore, and found the compression bars became stuck in their bores. To get these cutting without deflecting the bars it is crucial to grind the cutting tools correctly, and to set them correctly. The bodies are from cast iron, and work well if made to plan. I rarely use the bodies these days as I adapted the design to be used with the quick change tool post (below) which allows a more accurate setting for the cutting tips. |  |
| If you use a pillar drill for fine items you should have one of these available to you. In fact these should be sold with the drills to help prevent the usual problem with cut hands through work slipping when using a drill. Drill vices are reasonably common, and I don't understand why these things are not. As can be seen from the photograph it is simply a plate with a hole through, where the drill may pass, and a largish clamp tightened down by a couple of threads. The V-block locates via two pins on the finger plate, and the whole thing can be lined up with the drill chuck using the bar which locates in a bore in the V-block. This allows reasonably accurate cross drilling for most sizes between 3/16 and 1 inch. It is important to centre drill initially though, so you have to be very careful to make sure you don't disturb the setup changing from the centre drilling operation. |  |
| I am reasonably good at regrinding twist drills off-hand in that they usually drill when I have resharpended them. However, I have always been worried about how the angles for chisel edge are controlled, and how the backing off angle is controlled. When using hand grinding methods I just guess, and it works for the greater part of the time, and sometimes fails. I brought a drill grinding jig from Drapers which worked surprisingly well, but was difficult to set up in a convienient way without giving it its own bench grinder. Also I could not see how the angles could be fully controlled using this jig, so I decided to build my own. I decided that the only way in which the angles could be fully controlled using any jig I could build would be to use facit grinding which is supposed to confer some advantages on the finished drill. The jig is simply a stop which clamps the drill in a V which can be advanced using a micrometer screw. You simply select the chisel angle using the tilting table on the grinder, then clamp in the drill and advance it slowly locating a strake an the bottom of the jig against the edge of the tilting table. The drill is turned over to grind the other side, then the backing off can be ground in the same way. So far the results are encouriging, but not immediately brillant. There is too much movement in the jig, and too many irregularities in the current grindstone to give utterly consistent grinds. I am sure that with practice and modification this will eventually produce precise regrinds of twist drills. |  |
| Anyone who uses a lathe with any regularity for one off items will realise that a substantial proportion of their time is taken up with changing tools. If you just have a standard clamp type toolholder the operation is tedious as all the packing has to be adjusted to raise the cutting edge to centre height. Having grown tired of this I ordered a Hemingways kit for a quick change toolholder, designed by Mr. Archibald. Mr. Archibald's plans took some adaptation for the Lorch but is certainly worth the difficulties of milling dovetails for the speed at which tools can be changed and set to centre height. |  |
| Knurling is one of those processes which is more or less impossible without the correct tool. I made one from a kit from Hemingways, who supplied everything, and designed by Mr. E. Riley. This tool is a super design, and can be made straight to plan. As can be seen from the photograph I added a small stud to hold a set of knurls so they wouldn't become seperated from the tool. The only awkward bits are milling the slots through the arms. This can probably be done on a lathe, but you will need a long series 1/4 inch slot drill. My father and I did this bit of the construction on his milling machine, and we only had a short 1/4 inch slot drill, so we had to play about milling the slots from both directions, which is possible, but doesn't get perfect results. |  |