Proper shape and construction of scrcw driver blades.
Proper shape and construction of scrcw driver blades.
it is impossible to maintain the correct degree of toughness unless you know the proper temperature at which this steel should be drawn. It is, therefore, usually necessary for the gunsmith to make his own screwdrivers out of octagonal chisel-steel. This is better than drill-rod, as it has a lower carbon content and is not quite so brittle.
The blades of these screw-drivers should be rather short, 2y/' to 3" long below the handles, as this gives you a better control over the screw-driver. The blades should be made in five or six different widths and thicknesses, governed by the size of screw slots in various gun screws, from butt-plate and guard screws down to sight screws. The handles should be made of hard-wood, treated with linseed oil, and they should be larger than like sizes of commercial screw-drivers. The handles should be fluted to give a good grip and a fairly heavy brass ferrule should be used. The blade is pinned to the handle by a cross-pin through the ferrule, handle and blade. These pins should be of steel and be a tight, driving fit through the blade shank.
The blades should be brought to a low cherry heat and quenched in oil, then polished and heated slowly until the color just changes to blue from purple, upon which they are again quenched in the oil.
A few center-punches and a prick-punch, which is a slender, pointed center-punch, will be required. Commercial punches are alright if you choose a standard brand.
Scribers for marking and laying out cuts are best made of steel phonograph needles, as these are very hard, have true-ground surfaces and are cheap. They may be set in a handle made of % rod by drilling a small hole in one end of the rod, holding the needle in the vise jaws and tapping the rod onto the needle, or the needle may be held in a Starrett #162 pin vise. When dull, the needle is discarded and a new one inserted.
These #162 Starrett pin vises are very handy for holding small pins to taper them slightly, reduce them in size or to round the ends of them. They come in four sizes and are inexpensive.
Steel scales in various widths, lengths and thicknesses are a necessity and in this connection I wish to call your attention to the set #423 of Starrett short rules, with handle. These come in four lengths in.this set; J4", y*" and 1The handle clamps onto them at any point, making it easy to reach into small spaces to make measurements. A scale graduated in tenths of an inch is very useful in setting scope bases the proper distance apart for target scopes.
A bevel protractor will be needed to measure angles or slope of cartridge cases in body and shoulder and tapers of other items such as ramps, sear angles, etc.
Two small hardened squares are used in setting scope blocks and receiver sights, these should be of high-grade such as Starrett or Brown & Sharpe make.
Starrett makes an adjustable small square, the #457 Improved Die Makers' square, which adjusts eight degrees each way from center, with which it is often possible to take an angular measurement in places into which nothing else will reach. It has two narrow blades, one of which is offset.
A center gauge is necessary for setting thread tools in the lathe and for checking lathe centers when re-grinding them.
Screw pitch gauges will be needed to measure the threads per inch of screws, as gun screws are not standard pitch.
Inside and outside calipers and dividers must be in the tool kit and in this connection I wish to mention that the round-leg dividers are much easier to sharpen than the flat-leg type.
The smaller sizes of telescoping gauges, such as the #229 Starrett, can be used to measure the diameter of holes from Yi" up and the gauge may then be measured by an outside micrometer to get the dimensions in thousandths of an inch for close fits.
In buying micrometers, the one inch size should be graduated to read to ten-thousandths of an inch. The larger sizes will do well enough graduated to thousandths of an inch. Do not buy cheap micrometers, but .buy standard makes, the service they give will be worth the price paid.
For measuring the diameter of small holes the Starrett company make a tapered gauge of eight leaves, graduated to read in thousandths of an inch. This is the number 269, it sells for §5.50 and will measure holes from Yi o" to Yz'. Both Brown & Sharpe and Starrett make an inside micrometer graduated in thousandths of an inch to measure from %0" to 1This is operated by turning the spindle, just as an outside micrometer is, but it reads in the opposite direction. These each sell for $14.00 and are well worth their cost.
Parallel clamps are used to hold receiver sight bases and scope bases in place, while drilling holes for screws. They are also handy for other uses in the shop, such as holding small parts for filing, by putting the small part in the clamp and putting the clamp in a vise. The small jaws of the clamp make it easier to get at the part for filing than if the part is placed directly in the vise jaws.
A pair of parallels or true-blocks make the best thing to place beneath the action of bolt-action rifles to square it up on the surface plate for mounting receiver sights, scope blocks or lining up a front sight straight.
Vee-blocks are used beneath the barrel, in connection with the parallels under the action on the surface plate. Vee-blocks are also used beneath the barrel on the drill press, or for holding any round stock to be drilled. One of these vee-blocks should be equipped with a clamp, so that work placed in them will stay in position.
A good inexpensive surface plate can be made from a piece of heavy plate-glass. Get a piece eight or ten inches wide and forty inches long and mount this on a piece of flat board, placing padding beneath the glass next to the board. Felt can be used for this padding, or newspapers do very well if used in thicknesses of ten or twelve pages, simply to take up small inequalities in the board. The glass can be held in place with a few wire lath nails driven in carefully around the edge, so that one side of the nail heads extend just over the top of the glass.
A good powerful magnifying glass is a very good thing to have to examine or measure fine threads, sear and hammer surfaces, bullet bases, etc. Swift & Anderson of Boston make a two-lens glass of ten diopters power with a pen-type flashlight inserted in one side of the barrel to act as a handle and to supply light for the* subject being examined.
Small flat, square and triangular carborundum stones may be bought from the Carborundum Company and white Arkansas stones, either soft or hard, can be bought from the Norton Company, These are used for hard fitting of small parts and for dressing sears and hammers in adjusting trigger-pulls.
Abrasive cloth in rolls 1" to wide is about the most economical way to buy it, but you will need a few sheets of the abrasive cloth also in the standard 8J/2" X 11" size. These come in almost any grit, down to crocus cloth. The wet or dry black sandpaper sold for automobile finish work is fast cutting and gives a smooth finish also and it is cheaper than carborundum cloth, but the backing, of course, is not so strong.
Emery cake can be bought in various grits for use in muslin or canvas buffing wheels. Carborundum powder in various grain sizes and flour of emery are used for lapping. Automobile valve-grinding compound makes a fast cutting lapping or polishing compound, but is too fast for use in barrels, although it docs well on bolt smoothing jobs.
The gas welding torch is a better tool on almost all gun work than the electric welding machine. The gas torch is better for joining two pieces of metal, as it heats the metal more thoroughly and makes a better bond thereby, for the electric welder heats only the point of contact in the small sizes applicable to gun work. On the other hand the electric welder of the spot-weld type is, perhaps, a little better for building up parts, especially hard parts, for the reason that it does not spread its heat so far as the gas torch does. Another drawback to the small type electric welder is that it often leaves a scale as hard as glass, that can be machined only by grinding. As much of the welding work on gun parts is done on very small parts, the airplane-type of gas torch is the easiest to handle on account of the fact that it can be cut down to a smaller flame than the larger type torch.
A small forge can be used for much work in the gun shop such as case-hardening, bending jobs, etc., but is not so good as a gas furnace for tempering work.
A gas furnace is usually an expensive item to buy, but a very servicable one can be built cheaply by experimenting somewhat on the type and size burner necessary. The furnace itself is built of firebrick, cemented with asbestos. A sheet-iron form is bent to the shape of a half-circle and the bricks are laid over this to form the upper part of the furnace. This is set on a fire brick and asbestos cement base and the steel form is withdrawn after the ccment has set. One end is bricked and cemented up, leaving a small hole for an outlet flue pipe connected to a chimney. The other end is fitted with a steel door faced on the inside with asbestos ccment in or on expanded metal lath. After the cement is all set hard, the whole interior should be lined with fire-clay.
The burner may be made of iron pipe, a line of pipe running along each side of the furnace, inside, about two inches away from the wall and from the floor. These pipes are connected to a supply-line. Along the sides of the burner-pipes a line of small holes should be drilled, facing inward and upward toward the center of the furnace, and here is where the experimental work comes in, getting these holes the proper size for the furnace you build. Your gas company may be helpful in designing this burner. The inner ends of these burner-pipes arc capped, of course, and the connection to the H" supply-line should be on the outside of the furnace, with a good needle-valve be tween the supply line and each burner-pipe, so that proper adjustment of the gas supply can be made. Cast-iron pipe with screw caps on the ends can be used to place parts in while being tempered as they should not be exposed directly to the flame. For pack-hardening, parts are packed in charcoal, bone or whatever you use inside this cast-iron pipe. The caps of this cast-iron pipe should have a few small vent holes drilled in them on the upper side. Cast-iron pots can also be used inside this furnace, with sand, lead, nitre or other mediums in them, in which to place small parts. The cast-iron pipe and the pots can be set up on firebrick, or on cast-iron holders, to bring them about to the center of the furnace or a little above center. The size of the furnace you build will depend upon the largest size items you think you will ever wish to put into it for heat treatment. If you think you will wish to use high temperatures of two thousand degrees or more, an air-blast must be added to the gas flame. This can be run into each y2" burner-line after the line leaves the y<supply-pipe and each air line should have a needle valve on it for fine adjustment to get the best results. Pyrometers to control temperatures inside the furnace, or rather to show temperatures inside the furnace so that they may be controlled, can be bought from Russel Electric Co. of 338 W. Huron St., Chicago, at very reasonable prices or from Illinois Testing Laboratories, Inc., 420 N. LaSalle St., Chicago.
For ordinary tempering work in a lead, sand or oil bath in a forge fire, or over a plumbers gasoline furnace, deep, fat-frying thermometers, registering up to 600 degrees, can be bought from $1.00 upward, or the tempering may be done in an electric oven of the common range type, which has temperature controls of the automatic type registering to 550 degrees. A gas-range oven will work as well, of course, just so temperature controls are accurate.
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There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.