Taper uniformity

When the shaft is available on which the wheel is to fit, it can be tried in the taper as this is machined (or reamed) in order to locate the wheel endwise correctly in which respect, should the taper bore be made slightly too large a reducing cut can always be taken over the face. sleeve can be fitted for a distance X to Alternatively, the bore can be sized obtain when the taper is at correct size from a reamer or mandrel, as at D, which in the case of a reamer, a sleeve is essen-may be...

Winding Small Springs

The following method of winding small springs may be of interest to readers. I have used it for a number of years after seeing a description in a handbook Kempe, I believe but it does not seem to be generally known. I. Tension springs. A piece of ebonite or fibre is held in the vice and two sets of holes are drilled. Those on the left serve to tension the wire which is threaded through alternately front and back those on the right act as bearings for nails or suitable size mandrels held in a...

Sets and joggles in small details

It is most difficult to set small details without distortion, especially those forming part of a locomotive valve-gear, due mainly to their relatively large cross section, compared to their length, and even when distortion is overcome, there is still the question of maintaining reasonable accuracy. The easiest way to overcome distortion and inaccuracy is to make a simple bending tool to use in the vice see Figs. 5, 6 and 7. The part to be set or joggled should be supported by a couple of pins...

Jigs for shackles eyes and chain links

Jig Cut Chain Links

The body of the shackle jig is a piece of plate as thick as the inside width of the shackle, with the edge radiused the same as the bottom of the U of the shackle. Three holes must then be drilled and reamered for the pins around which the rod will be bent. Pins A and B must not stand proud of the body more than one diameter of the rod being bent, C must project at least two diameters. As an added refinement to avoid flattening, A and B, but not C, can be formed rollers, held by a pin. Pin C...

Cutting Square Threads

In the cutting of square threads the front cutting edge of the tool must be at right angles to the helix of the thread, and the tool itself can resemble a parting tool as the width of the blade should narrow slightly where it joins the stock, to provide clearance. You must add about 0.003 in. to the width of the cutting edge so that the tool can move between the flanks of the thread when you are finally gauging the work. It is also essential that the top rake should be correct in relation to...

Turning and Boring Phosphor Bronze

It is usually advised to have no top rake on tools, although I prefer just a very little myself. Take the first cut deep enough to get well under the skin, run slow, with the back gear in if necessary this will be desirable if cast steel tools are used. Do not use too fine a feed for roughing. When skin is removed inside and out, speed up the lathe, but phosphor bronze cannot be cut at the same high speed as brass. Grind twist drills as per sketch for cutting brass and phosphor bronze, but only...

Clasp Nut Engagement Stop

Whilst I cannot speak for all M.L.7 lathes, I found that mine, at least, suffered from the fault of being without a definite stop to determine the degree of engagement of the half-nuts with the leadscrew, it being found that when the lever was depressed to effect engagement, there was nothing to prevent the half-nuts gripping the screw with such force that a very considerable torque was required to effect the rotation of the leadscrew it was found almost impossible to move it when attempting to...

Winding Helical Springs

By means of the device shown in the sketch, open or close wound springs can be made with a minimum amount of trouble and danger in the ordinary lathe. The correct diameter of the mandrel A can only be obtained by trial one made seven-eighths of the inside diameter of the required spring is generally about right. The device consists of the shank E which is held in the tool-post of the lathe. The front portion is cut away to rest against the mandrel A the wire being kept taut by passing it...

Lathe Centre Gauge and Scriber

This very useful tool can be easily made, and serves the purpose of a gauge for setting the tool at centre height on the slide rest, also in lieu of a scribing block on the lathe bed, and, having a larger base, is better for marking out and setting work true in the chuck. For marking graduations in dividing work in the lathe it is far quicker and better than a screw-cutting tool clamped on the top slide on its side. The marking point can be swivelled and set to mark either a face or edge and...

A simple remedy

With a view to obviating this unpleasant set of potential trouble-making circumstances, and to introduce a measure of reliable consistency to the operation of screw-cutting, it was decided that some sort of depth engagement stop must be fitted to the half-nut mechanism and, after removing the lathe apron and giving the matter a couple of hours consideration, the following method was adopted as being the simplest solution, and one which would not spoil the external appearance of the apron. Fig....

Query Form Tool of Complicated Shape

I wish to make a form tool, for use on the lathe, to the shape shown in the accompanying sketch. The exact radius of the portion marked (X) is not important, but I wish the vees to be clean and sharply pointed. My difficulty is that I do not see how I am to grind these vees on an ordinary bench grinder, which is all the grinding equipment that I have. Your help and suggestions would be much appreciated. Form tools of complicated shape, such as you require, cannot be ground accurately on an...

Boring Bar Attachment

One of the tools we have to use on the lathe is the boring bar, and when it comes to cutting a slot in the bar and fitting cutters for various jobs, the time and labour becomes a consideration. Convenient way of mounting light cutters on boring bars. The attachment I am describing was designed for facing the sides of the crankshaft bearings in the main castings of small power gas engines, and the type of cutter used has done me a good turn on lots of jobs. I have used a cutter of this sort (see...

How to Plane Small Gears

Although small gears can be bought in many sizes, they must sometimes be made at home because a standard one is not right in size, in number of teeth or in material. You may need a steel gear instead of a standard one of brass or a gear which is to hand may have too few or too many teeth to give the required ratio. And there is the satisfaction which comes of making all the parts of a model or mechanism yourself. Providing that the gears are of fine pitch, planing with a form tool in the lathe...

Contents

SECTION 1 Lathes and Lathework 3 Forming and Finishing a Screwthread 10 Lathe Centre Gauge and Scriber 17 Sensitive Drilling Attachment 18 A Simple Lead Screw Chip Guard 26 Setting Lathe to Turn Parallel 30 A Centre-spacing Punching Tool 32 Turning and Boring Phosphor Bronze 33 Query Form Tool of Complicated Shape 34 Curing the Incurable Chuck 34 Tightening Adjusting Screws on Cross Slides of Small Lathes 35 Overcoming the Deficiencies of Inaccuratc Machine Tools 37 Small Bends, Sets and...

File Cleaning

We are often recommended to clean a file by rubbing it across the teeth with the end of a piece of brass strip brass presumably being specified as the least likely material to cause a premature blunting. This is strange, when you consider that files are made to cut steel, including carbon tool steels, some of which are quite hard even in the annealed state silver steel, for example. I have a very fine (and favourite) file in constant use for finishing diameters such as may be required to very...

Final adjustment

After fitting the stop and re-assembling, it is a simple matter to make the final adjustment. When the half-nuts are open, the stop adjusting screw is readily accessible at the base of the apron, and should be slackened off until the half-nuts grip the leadscrew, whereupon, by getting the feel by hand twiddling a change gear mounted on the leadscrew in the orthodox position, the stop adjusting-screw should be screwed up by small increments and the half-nuts operated until the lead-screw is free...

Twisted Rods

Sir, With reference to your problem of twisted brass rods. I have recently completed a Fowler Big Lion and the method I employed was as follows - Square brass tube was cut to 1 in. plus, annealed and filled with lead, a bush with a square hole was fitted in the chuck and another in the tailstock. The brass was then placed in the holes and the chuck pulled round the required number of turns, after which the lead was melted out. Incidentally I worked at Savages, King's Lynn, for a brief period....

Simple Lead Screw Chip Guard

Zyto lathe, I decided to make a lead screw chip guard, as there was not one fitted. I obtained a piece of steel gas pipe about 4-ins. long, internal diameter a little larger than the diameter of lead screw, sawed it down in half lengthwise, and then riveted a piece of steel strip on to it, bent at right angles. I next screwed the end of the strip to the lathe saddle and adjusted the guard so that it just travelled above the lead screw. This fitting is well worth making,...

Small Bends Sets and Joggles

The appearance of a model, or indeed any example of engineering work, is much enhanced if all the minor parts show evidence of neat and careful workmanship. Such bent components as shackles, eyes, and chain links in bright mild-steel present certain difficulties in this respect, but it is possible to produce them in such a way as to avoid spoiling the original finish with hammer marks, bruises and burrs. If one has considerable dexterity with round-nosed pliers, and the work is small enough in...

Cutting Metric Threads

The use of a 127-toothed wheel for metric screwcutting on an English lathe By Geo. Gentry July 1955 This article relates to a problem which is constantly recurring in both amateur and professional workshops, and it is proposed to deal with it in some detail to satisfy the requirements of querists who have asked for advice on how to produce metric threads on lathes with fractional-inch pitch lead screws. In the particular instances, the pitch of the lead screw is not specified, but it will be...

Making Screws

It may seem that notes about this subject are superfluous now that screws are produced and sold at small cost and in almost any size and shape for general mechanical construction. The kind I am implying are those used for connecting parts together, round head, cheese head, countersunk patterns of screw, threaded along the whole or part of the length of the shank. They are made in quantity, as bolts, nuts, keys, pulleys, line shafting and other general engineering supplies are produced...

Centre Spacing Punching Tool

Bradbury Winter May 1927 It often happens that a series of holes are required in a circle, either on the face of a job or on the outside edge. To make a circular scratch and cross scratches and centre punch the points of intersection is inaccurate and slow. For such jobs I have a piece of J- -in. square steel, about 4 ins. long, with a hole, about No. 45, near one end, and in this hole a piece of steel wire in. long Small centre punch mounted for use in the lathe. is a good sliding fit....