Spindles for Small Shop Metalworkers E-Book

Harprit Sandhu

• Herausgeber: Fox Chapel Publishing
• Kategorie: Lebensstil
• Sprache: Englisch
• Veröffentlichungsjahr: 2022

Seitenzahl: 274

Beschreibung

The possibilities of what you can achieve in your workshop are greatly enhanced if you have spindles to use with your lathe! A complete and crucial guide for amateur engineers, this book describes the design, construction, and use for a variety of useful spindles that range in shape and size. Featuring over 150 scale plans, line drawings, and a collection of helpful data tables, this metalworking guide clearly outlines several techniques for milling, grinding, and drilling spindles that are easy to make and have as few parts as possible. Author Harprit Singh Sandhu is an American engineer and the founder of Rhino Robots Inc. The chief designer of the 'Rhino' series of robots, he is also a machinist, woodworker, and clockmaker – the latter of which inspired him to design and build the spindles described in this book.

Leseprobe

Copyright © 2022 by Harprit Sandhu and Fox Chapel Publishing Company, Inc., Mount Joy, PA.

Copyright © Special Interest Model Books Ltd 2006

First published in North America in 2022 by Fox Chapel Publishing, 903 Square Street, Mount Joy, PA 17552.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior permission of the copyright holder.

Print ISBN 978-1-4971-0195-1

eISBN 978-1-6374-1129-2

Library of Congress Catalog Number: 2021945105

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Contents

  1Introduction

  2Designing a spindle

  3The basic spindle

  4Mounting the spindle

  5A smaller No 2 Morse taper spindle

  6The micro spindle

  71.000 inch diameter spindle (25mm)

  81.250 inch diameter spindle (32mm)

  9Light, tool-post OD grinding spindle

10Light, tool-post mounted ID grinding spindle 1.500 inch diameter (38mm)

11Simple No 1 Morse taper spindle

12Vertical spindle or gear cutting frame

13A spindle with tapered roller bearings

14Driving the spindles

15Notes on using the spindles

16Notes and ancillary information

APPENDIX 1SI drawings

APPENDIX 2UK equivalent tables

CHAPTER 1

Introduction

This is a book about making auxiliary milling and grinding spindles for use with a small lathe. Although the experienced engineer might pick up a trick or two, the book is aimed primarily at beginners. All the spindles can be made in the amateur engineer’s workshop by anyone with average machining skills. The spindles are described for making on and use with the Myford Super 7B lathe, however they can be adapted for use with other lathes with relative ease.

The spindles range in size from 0.750 inches (19.05mm) in diameter to 2.250 inches (57.15mm) in diameter and are suitable for a variety of purposes. A novel design for a gear cutting frame that uses sealed ball bearings at each end is also included.

The book provides the novice amateur engineer with a ready source of information and discussion about the construction of some of the various types of spindles that are needed by the amateur from time to time. Wherever appropriate I have given reasons behind the decisions made to help give the builder more confidence in his or her decision to make any modifications for experimentation.

These spindles are not intended to be industrial grade, heavy duty spindles that will give years of service in the dirtiest environments imaginable but rather they are designed to be spindles that are easy to make and use in the amateur’s workshop. I have made every attempt to keep the number of components needed to make any spindle to an absolute minimum. I have tried to minimize the need for sophisticated equipment as well as the need for highly skilled work. Of necessity, all the spindles are of one of two basic designs, each being easy to follow.

Keeping the designs simple meant that the spindles had to be of one or two basic designs. In one design, two bearings are used at the front end and the back bearing is free to move in the housing. Both inside and outside races are clamped on the front bearings and only the inner race is clamped on the back bearing. In the second design, only one bearing is used at each end but both the inner and outer races of each bearing are clamped or glued. The second design was slightly harder to build in that it was a little more difficult to get the spacers just right. However, you get a spindle with less axial play in the bearings. Since all spindles can be made to either design, you have a choice as to which design you decide to use on your spindle. You can also combine features from both designs into the spindle you make. (Spindles with glued in bearings are a form of clamped bearing spindles.)

Since the usefulness of a spindle is completely dependent on the accessories that can be used with it, I have used standard lathe nose threads and tapers when possible so that all the standard lathe accessories and other standard components can be used with these spindles. In particular I used the Myford Super 7 spindle nose standard with the No 2 MT (Morse taper) on the cartridge spindle in Chapter 3. This will allow you to use all the tapers, collets, collet closers, mill holders and chucks that are available for use with this standard spindle nose. The use of the No 2 MT, which allows a ½ inch shaft to be held very accurately, makes it much easier to make arbors for clock cutters etc. because these arbors can now be made with straight shanks and held accurately with relative ease.

In the small grinding spindle I considered it best if the many arbor mounted grinding wheels, cutters and arbors as well as the collets and collet closers that are available for the ubiquitous Dremel Moto Tool (widely available, but in case of difficulty contact Microflame Ltd, Vinces Road, Diss, Norfolk, IP22 3HQ; Tel. [phone]) were able to be used with this spindle. These wheels are very inexpensive and serve the needs of the amateur engineer well. Here my main interest was to have the ability to grind small parts and tools for projects like clock arbors, pinions and other small parts with precision. This spindle will also allow the making of small precision cutters that are often needed by the amateur engineer. With a little care and patience, it could also be used to grind fine threads.

The micro spindle was my effort at designing the smallest possible spindle with ball bearings. This has an outside diameter of 0.750 inches (20mm) and the body is 4.000 inches (100mm) long. Here again I designed with the Dremel Moto accessories in mind as a resource. This is a spindle more suited to the many lathes that are smaller than the Myford Super 7. Since I do not have access to one of these lathes, and have never used one, I was unable to offer a design for a spindle mounting that I had actually built and used. In other areas I have presented some ideas that will be useful to the more resourceful amateurs.

I have also included a couple of designs for which essentially only the drawings are included. The construction of these spindles is very similar to the construction of the other spindles in the book so the repetition of the instructions is avoided by doing this.

I have avoided using any exotic materials altogether and every component and all the raw materials should be readily available on either side of the Atlantic. I have recommended the use of free machining materials throughout. These materials are easy to use, their machinability is equivalent to that of brass. They are more than strong enough for the applications that we have in mind. Their slightly higher cost will be more than paid for by the added pleasure of using these materials. I have avoided the use of exotic tooling except for the use of the reamers for the Morse tapers. These reamers simplify making these tapers to the point that not using them would be counter productive. Since these are not tools that you need every day, it might be possible to arrange to share with other amateur engineers.

For those who prefer to work from fullsized, formal engineering drawings, these are available, for a small charge, from Nexus Special Interests Books, Nexus House, Boundary Way, Hemel Hempstead, Herts HP2 7ST. These drawings are on A4 paper and are available in either imperial or SI dimensions.

The spindles are designed to be built on a small lathe with a minimal need for milling operations. Most of the work I carried out was done on a Myford Super 7 with the average complement of accessories. I did use a 5.000 inch (10.000 inch in the USA) South Bend lathe to do the heavy work when a lot of material had to be removed. However, all this work could have been done on the Myford Super 7.

Much of the success in making anything is not simply a matter of having a set of drawings for the project but also has to do with knowing how to make the setups and in which sequence to do the work so that it turns out right. I have made an attempt to show the way in all these projects. Both setups and sequences with the reasons for using them are provided. These are especially critical in the construction of spindles that are intended to be high-speed precision tools. I have tried to show the builder how the inherent properties of the lathe and the standard components provided by the manufacturer can be used to their best advantage in building these projects.

The bearings used can be a mixed bag of metric and imperial sized bearings. In general the sizes are not critical and whatever is available in your area can be used by changing a few dimensions.

With reference to the cartridge spindle in Chapter 3: if you have a Myford Super 7 or similar lathe and you are going to make only one general-purpose spindle for your shop, this is the one that you will want to consider making. It gives you the greatest versatility of all the spindles in the book and is described in the greatest detail. Although this spindle might be a little larger than what you had in mind, it is very versatile. Modify the spindle nose to suit your lathe and the accessories that you have at hand if you are not the lucky owner of a Myford Super 7B lathe.

Other spindles offer special advantages that are needed under special circumstances or are better suited to smaller lathes or to special setups.

If you decide to make any of the other spindles, first read Chapter 3 a couple of times to get the principles and techniques described well in mind. It will be a tremendous help to you in building your spindle, especially if you are a beginner.

I could not resist looking into what was needed to make a spindle with tapered bearings. The design that I came up with is provided for your consideration in Chapter 13. If you first build the 2.250 inch diameter spindle and then decide to build this spindle it will be worth your while to make it 2.250 inches in diameter also so that you do not have to make another set of mounting plates. My spindle is 2.000 inches in diameter to test how small a taper bearing spindle could be. Going to 2.250 inches will allow the use of slightly larger bearings and a 1 inch diameter for the internal spindle at the bearings.

All the information and drawings needed to allow construction of the spindles are included in the book. Materials needed to make the spindles are readily available and every attempt has been made to make sure that nothing that is hard to get is included in the projects.

I built only those items for which there are photographs. If you do not have a photograph for reference you need to exercise more caution when building in that there is a slightly higher possibility of errors in the dimensions given for these designs. I did not build any spindles to metric dimensions so extra caution is needed with these drawings also (see Appendix 1). US sizes for the nuts and threads have been used throughout the text – please refer to Appendix 2 for UK equivalent tables.

This is my contribution to keeping this wonderful hobby strong – a hobby that has provided me with endless hours of total delight.

Should you have occasion to discover any errors in the information provided, I would appreciate it if the information could be forwarded to me so that I can make the necessary corrections as soon as possible for the benefit of future amateur engineers and experimenters who build these spindles.

Good luck and happy turning.

Harprit SandhuChampaign Illinois, USADecember 1996

The six spindles made by me to verify the construction methods described in the book. Improvements have been incorporated into the drawings.

E-mail:[email protected]\par

Facsimile: 217-356-6944

Telephone: [phone]

(Answering machine on 24 hours a day)

Snailmail: H S Sandhu, 705 West Kirby

Avenue, Champaign, Illinois 61820, USA

CHAPTER 2

Designing a spindle

This chapter contains a very short tutorial/discussion on the design of the spindles in the book. (This is very much a simplified approach and no consideration is given to the making of calculations which are a must in any serious effort.)

The basic idea is that there is nothing difficult about designing a simple machine if one goes about it in a methodical way. The ideas presented are applicable to any basic design project.

The facts before us in this particular case are as follows:

• Before there is a spindle, there are drawings. It is much easier to work from a drawing that has been carefully thought out.

• Before there are any drawings, there will have been some sketches. We have to make sketches and work out the dimensions and positional relationships before we can make the formal drawings.

• Before there are any sketches, there must have been some ideas. Neither do sketches have a life of their own. They are expressions of ideas that we have about the machine that we thinking about making which in turn are determined by the uses that we will put the machine to. These are the purposes for which the machine is being designed.

• The ideas on which we are going to focus have to do with designing spindles for use by the amateur engineering community. These spindles will be used for a variety of purposes, the main ones being light milling and grinding applications.

• The best and most popular amateur’s lathe on the market is the Myford Super 7B. At the risk of sounding like I have lost my mind early in the game, I will say that no other manufacturer even comes close to providing such a good lathe. For this reason we will design for this lathe.

• Most amateur engineers, in general, and in spite of some evidence to the contrary, do not have a lot of money to spend on their hobbies.

It is always a good idea to keep track of what you are thinking about by writing it down, so let us list our conclusions.

With the above facts in mind we come to the following conclusions:

• We will design relatively small spindles.

• They will be mounted on sealed ball bearings.

• They will be belt driven.

• We will design for mounting to the Myford S7 tables and slides etc.

• We will accommodate the use of Myford accessories when possible.

• We will design to allow versatility of use.

• We will keep costs down.

• We will keep down the skill level needed to build.

• We will limit the time needed to build.

• We will not use exotic materials because they are expensive and hard to find.

The Myford mounting slots are 1.562 inches (39.67mm) on center and are suitable for hold down studs that are 0.250 inches (6.35mm) in diameter. This tells us that the spindle has to fit on a grid 1.562 inches (39.67mm) on center. Our mounting bolts will be either 1.562 inches (39.67mm) on center or twice that which is 3.125 inches (79.35mm) on center.

Figure 2.1    Mounting grid for Myford S7 tables. Studs are 1.562 inches (39.67mm) on center in both directions.

So the mounting grid looks like Figure 2.1. We will start by placing critical components on the grid. At this stage we are working with sketches although I am showing these as drawings in the book.

If we are going to use the Myford accessories with this spindle, we need to use the same spindle nose as the Myford uses. Let us assume a 2.000 inch diameter spindle with a Myford spindle nose at one end and a pulley at the other end. We will represent all this with simple rectangles in our sketches.

Now let us position our spindle sketch on the grid. Our spindle can be positioned to use either a single grid spacing or a double spacing as the conditions dictate. The next two figures show where the spindle would be in regard to the grid for each of these mountings.

Figure 2.2    Mounting the spindle on short spacing.

Figure 2.3    Mounting the spindle for long spacing.

The smaller spindles will be able to make use of the type of mounting shown in Figure 2.2 even if the studs have to be within the housing of the spindle (as long as we can miss the spindle bearings).

The larger spindles will have to have the studs straddle the spindle as shown in Figure 2.3. This takes up more room but also gives us more space to work with.

Now that we know where the spindle nose is with respect to the mounting studs, we can think about placing our bearings to miss the studs. We need two bearings, one in the front and one in the back. The front bearing is more critical because it is the one that bears most of the load and for this reason it should be as close to the cutter as possible. With this in mind we will try to place the front bearing as far forward as we can and position the smaller rear bearing as is convenient.

Figure 2.4    Bearings, spindle, pulley and hole added.

Let us place some bearings in the spindle to see how they look for position.

In a milling spindle, most of the load is taken up by the front bearings. Industrial milling machines often use three and four bearings together very close to the nose. We will use just one in our design. At this stage, the basic concepts are in place and we are ready to work out the details.

How we hold the bearings will be critical. The front bearings must be integral with the spindle. This means that both the outer and inner races have to be clamped tight to the housing and spindle respectively. It will be best if the back bearing is positioned exactly but, with the equipment at our disposal that does not seem to be likely, so I am going to suggest that we clamp only the inner race of the back bearing and let the outer race slide back and forth in the housing. If you analyze the loading on the spindle you will see that the axial load on the back bearing is minimal. Its major purpose is to provide radial support for the back end of the spindle. (There are other ways to control the distance between the outer and inner recess of the bearings and some of these are shown in other designs in the book.)

The concepts presented above are shown in Figure 2.5. Keep in mind that this is where we clamp the races. The races are held at their OD by the housing and at their ID by the spindle so these directions will be properly constrained if we turn the spindle parts to close dimensions.

Each set of arrows represents a clamping device. We need three clamps or nuts. The other side from each nut will be either the body of the housing or the spindle itself. Let us draw these in.

Figure 2.5    The points where the bearings will be clamped. The double bearings are just an idea at this time to explore the possibilities.

Figure 2.6    The points where the nuts will be used.

This essentially is the end of the sketching phase. We may go through many sketches and many permutations of what we want to do but eventually we will end up here and be ready for the formal drawings. The rest of the design process has to do with the selection of the proper bearings and the design of the various components so that they will work together in the way that you want.

When all this is put together, we get a spindle that looks some thing like Figure 2.7.

Figure 2.7    The completed spindle design. One front bearing has been removed in the final phase of the design.

This spindle with one row of bearings, in the front, and with some minor modifications, is described in some detail in Chapter 5.

When you design a machine, no matter how simple, you have to have the means of making it well in mind. As a part of this you should also have the machining sequences for all the machines that will create the mechanism in mind. In this way a viable product will be created. Not everything that can be dreamed up on a drafting table or computer screen can be made and not everything that can be made can be made economically. It is an important part of the engineer’s art to design machines that are useful as well as viable in the marketplace. Cost and performance are the most important considerations. Next come safety, aesthetic appeal and environmental responsibility.

Each chapter in the book takes it from here and shows you what you need to do to make each of the various components that go into each spindle.

Where spindles are similar to ones that have already been discussed in detail, detailed drawings are provided with only minimal discussion. You should refer to the detailed discussion provided for the other spindles when making a spindle for which only drawings are provided.

Instead of providing imperial dimensions and converting them to SI units all over the drawings, I have chosen to provide two sets of drawings for each spindle (see Appendix 1 for metric drawings). This avoids the use of strange dimensions that I find very distracting. There is no reason to dimension 1.000 inch as 25.4mm when the proper thing to do is to make a new drawing where 25mm can be used without apology. (1.000 inch is pretty close to 25.4mm because the next three numbers after 25.4 are zeros.)

Some random thoughts on small spindle design

Collets and Morse tapers make a considerable difference in the usefulness of a spindle. A No 2 MT, which is much more useful than a No 1 MT, can be fitted in spindle that is smaller than the Myford Super 7 spindle if you are willing to take the time to make a collet closer for the Myford collets to match. Since the critical components are the No 2 MT collets we have to work to their dimensions.

The collet closer is easily made in two parts, much the way the Myford closer is made except that in our case we will silver solder the two parts together rather than forming them together as Myford does. This has to be done to get the full depth threads that are needed.

The other alternative is to “not use” a collet closer but rather to draw the tapers in with a draw bar. Morse taper collets that do this are available but the Myford collets cannot be used to do this. However, you may have to buy one ⅜ inch (approx 10mm) or ½ inch (approx 13mm) collet to hold all the arbors you make and you can buy these collets with drawbar threads in them.

It is also possible to make spindles without using ball bearings and the spindles so made can be smaller than those that use ball bearings. There may be an advantage here when outside diameter is critical. I feel that the ball bearings give a much better chance of success and that they provide the performance and durability needed.

Needle bearings are not suitable for use here (even with extra thrust bearings added).

CHAPTER 3

The basic spindle

Introduction

There are only five turned parts and two modified parts in this spindle. There are also three bearings, a key and a nut. It accommodates all Myford nose chucks, plates and accessories.

Every serious amateur engineer, who does not own a milling machine, will need to perform milling operations on something that is being held in the lathe chuck many, many times during his amateur career. In the amateur engineer’s shop this is best done with a carriage-mounted milling spindle driven by an auxiliary motor.

Figure 3.1    Cross section of a cartridge spindle. Note: besides the bearings there are only 7 parts to be made.

The spindle is described as being a “cartridge spindle” – it is in the form of a cartridge that can be placed in any suitable chamber or holder. Cartridge spindles are the most versatile spindles. I selected a cartridge design because I had a couple of applications in mind for the spindle beyond basic milling and wheel cutting.

Figure 3.2    Main features of a cartridge spindle.

This chapter describes the design and construction of this cartridge spindle which is suitable for general-purpose use in the machine shop. Although it may be considered by some to be a bit large for fine work it is easier for most beginners to work on a larger spindle.

If you are going to make only one general-purpose spindle for your shop, this is the one that you will want to consider. It gives you the greatest versatility of all the spindles in the book and is described in the greatest detail. Other spindles offer advantages that are needed under special circumstances or are better suited to smaller lathes or to special setups.

Note

Do not scale any drawings in this book. Always go by the dimensions given. Both imperial and SI (metric) drawings are included in this book (see Appendix 1 for metric drawings).

Figure 3.3    Nomenclature used throughout the text.

The design requirements

The more I thought about it the more I wanted to try my hand at making one of the many wonderful clocks designed by John Wilding, but one thing had to be made first – a milling spindle to cut the gear teeth. So I researched the back issues of Model Engineer that I have access to, one thing led to another and before I knew it I was on my way to writing this book about spindles.

My prime consideration was that the spindle should be designed to be easy to make. Anyone with average turning skills should be able to make it without difficulty. However, this is not a minor undertaking because relatively large amounts of metal have to be removed in the course of a spindle project like this.

I have two lathes in my shop, a well-equipped 3.500 inch (90mm) Myford Super 7B and a well-equipped 5.000 inch (125mm) South Bend toolmaker’s lathe. I will describe the work as if done entirely on the Myford although I did do some of the work on the more powerful South Bend to speed things up where large amounts of metal were to be removed.

The basic 2¼ inch (57.15mm) diameter spindle and its mounting clams. This spindle has the same nose as a Myford S7 lathe and can be used with all Myford nose mounted accessories.

I decided that it would be best if as many of the Myford accessories as possible could be used with the spindle. This means that the spindle should have the same spindle nose as the Myford Super 7 lathe. This would allow the use of all the collets, the collet closer, the milling cutter holders and similar devices with this spindle. Of course there are times when a chuck needs to be mounted to a spindle (I had a 3.000 inch (75mm) chuck in mind but the 4.000 inch (100mm) chucks can also be used and work fine). The spindle also had to be designed so that it could be mounted on the bed of the lathe, on the cross slide of the lathe as well as on the vertical slide. All this led to the cartridge design that I chose.

I also wanted to experiment with milling threads and this spindle is designed to be heavy enough to do that. I hope it will work – at the time of writing I have not yet tried this out.

So the design requirements for the spindle came down as follows:

• Ease of construction – it is designed for the amateur.

• Low cost – free machining steel is used throughout.

• Long enough to span the vertical slide to accommodate the drive belt.

• Complete Myford Super 7 spindle nose threads for flexibility.

• Internal No 2 MT so that Myford accessories can be used.

• Common, easy to find, sealed bearings for ease of construction.

• A low maintenance design.

The uses in mind during the design phase were as follows:

• Cutting clock gears – this was my primary purpose for making the first spindle.

• General-purpose day-to-day milling.

• As the occasional grinding spindle for light grinding using arbor held wheels.

• And, very important, general experimentation.

Materials required

The materials below are required to make the spindle. See text and drawings for the dimensions of the finished parts.

A spindle nose equivalent to the Myford needs to be made of 1¾ inch (45mm) stock i.e. the diameter of the flange that backs the mounting plates for the chucks etc. A quick look at the bearing catalogs confirmed that the spindle design could be accommodated within a 2.250 inch (55mm) diameter spindle housing with a little work. This large spindle diameter (to accommodate the No 2 MT) leads to the need for heavier bearings, which fortunately, are desirable in a milling spindle.

Part name

Material*

Diameter

Length

Housing

Steel

2.250in (55mm)

4.375 in (120mm)

Spindle

Steel**

1.750in (45mm)

6.750in (175mm)

Front bearing cap

Steel

2.250in (55mm)

0.375in (10mm)

Pulley

Steel

2.250in (55mm)

1.000in (25mm)

Front bearing cap

Split collet

Steel

2.500in (65mm)

0.375in (10mm)

Nut for front bearings

Steel

1.750in (45mm)

0.500in (13mm)

Nut for pulley***

Steel

¾ by 16 thread per inch, purchased 18mm by 1.5mm

Bearings

Purchased to suit, see discussion

* Use free machining steel throughout.

** This part absolutely must be an easy-to-machine steel so that we can cut/ream the No 2 MT without difficulty.

*** See Appendix 2 for UK equivalent

The spindle I made uses inch materials and metric bearings because that is the how it worked out at this time! To simplify matters, the designs presented in the book use either all imperial dimensions of all SI dimensions (see Appendix 1 for SI drawings). I intend to explain the reason for using the dimensions that I used whenever applicable. Incidentally the new digital calipers are a real convenience in that they allow you to change between inch and metric dimensions with the press of a button! Since I am not used to metric dimensions, I was able to convert to inches whenever needed to confirm that I was in the ball park. I just don’t feel at home with exactly how much 7mm is but I am quite comfortable with 0.2755 inches.

All the components of the basic spindle. The emphasis is on designs that use as few components as possible for ease of construction.

Bearings chosen

Nose end bearings

Number required

2

Inside diameter

1.000 in (25mm)

Outside diameter

2.000 in (50mm)

Width

0.375 in (10mm)

Seals

Both sides

Shields

None

Type

Deep grove bearings with axial and radial load capability

Alternate

Angular contact bearings

Tail end bearing

Number required

1

Inside diameter

0.750 in

Outside diameter

1.750 in

Width

0.375 in

Seals

Both sides

Shields

None

Type

Deep groove bearing

Alternate

Standard load bearing

(Note: the axial load on the bearing is almost zero)

Bearings discussion

The selection of bearings is not critical but should always be considered carefully. In our case we have two considerations that will dictate our selections. We want to keep the cost low and we have to be able to accommodate a shaft that will have a No 2 MT inside it. These two considerations resulted in the selection of the bearings specified above. Many other bearings could have been used. Do not let the availability of bearing put you off – any bearing that you can get your hands on can be used.

Bearings are made in more forms than you can imagine. Our interest is in bearings that are designed for