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Looking To Buy A Metal Lathe?

08/01/2011 By Leave a Comment

If you are looking to buy a metal lathe and want to get yourself a bargain then you can often find one on ebay. The picture listing at the bottom of this post is for a Myford Super 7 Metal Lathe for sale with accessories. You will have to be quick as this one will be gone in 5 days.

 

Before you buy a Myford Lathe then I would suggest you read this helpful used metal lathe buyers guide.

 

If you find you have missed the one below you can always visit the metal lathe for sale website to see the current selection of Myford Lathes for sale
SOLD

Filed Under: Readers Projects

How To Centre A 4 Jaw Chuck – Video Tutorial

05/17/2011 By Leave a Comment

Here is a great video tutorial from Mike freeman of Mikes Models where he demonstartes how to centre a bar in a 4 jaw chuck on his myford lathe . He starts by cleaning the surface of the metal bar he wants to turn in his lathe and then inserts it into the jaws of the chuck  and then tightens the jaws but not too tight. He then brings the dial indicator as close to the chuck as he can without it fouling the jaws. He goes on to demonstrate a simple process of revolving the chuck to find the high spot on the bar.

He identifies the jaw at the high spot and then turns it through 180 degress to get to the jaw at the lowest spot and loosens off the jaw. He then turns the chuck back to the high spot and tightens the high spot jaw. He rotates the chuck and you can immediately see he has reduced the hiegth on the dial. He then repeat this process checking the reading on the dial at each turn. as the adjustment continues the high spot varies between 2 jaws and a simple adjustment is shown on how to address this. As each adjustment is made the high point reduces by degrees. each adjustment is made until the gauge measure less than 1000 th of an inch.

This simple technique is easily seen and understood

Watch the video below

Filed Under: Readers Projects

Myford Super 7 Lathe Keyway Slotting Tool

04/14/2011 By Leave a Comment

Myford Super 7 Lathe Keyway Slotting Tool demonstrated in a short video using a myford super 7 lathe. The video shows a keyway tool copied from an idea by malcom Parker Lisberg who adapted a tool from the original myford version. The video shows the lathe and tool in operation and describes the proceess used. For any myford lathe owner this short video is well worth watching.

Filed Under: Readers Projects Tagged With:

Myford ML 7 Lathe Turning Project Chess Set (Section 2)

11/18/2010 By Leave a Comment

Readers article supplied by Mike Freeman of Mikes Models Model Engineering Website on his use of a Myford ML7 to create a brass and aluminium chess set in his workshop.

This article should be read in sequence after Myford ML 7 Lathe Turning Project Chess Set  (Section 1)

The Rook.

Rook 1.75” tall (44.45mm)

The Rook.

Rook 1.75” tall (44.45mm)

For a pleasant change we go back to the lathe after all the milling to make the rook which is made from 1” (25.4mm) dia bar. For the remaining pieces we now need to make a contour tool and the same contour tool will be used for all the remaining pieces.  I used 1/4” (6.35mm) square tool steel which was ground at the centre in to a V shape. Then some careful rounding off is required to get the desired shape [photo 11 close up of a contour on a rook]. It is best to keep both sides of the contour tool thin. Once you have something your happy with, it is best to test its cutting ability on a scrap piece of stock material.

I found a better performance was achieved by taking light cuts. It may take a couple of attempts to achieve a nice round shape that allows the tool to be advanced into the work. When satisfied, put the tool to one side as the first task is to chuck either the 1” (25.4mm) diameter brass or aluminum bar, having least 2” (50.8mm) protruding from the chuck.

After facing off the rook blank, lightly scribe a mark 1.75”(44.45mm)from the faced end. Turn the bar to 0.8125” (20.6375mm) diameter. Change cutting tools and with your contour tool place the centre of it ¾” (0.75” or 19.5mm) from the faced end. Take light cuts and carefully use the contour tool to depth of the contour,  which was 0.7928” (or 20.1371mm) in my case.

Return to the faced end, and centre drill, followed by successive drills out to 1./2” wide (12.7mm) and 0.250” (6.35mm) deep.  Change to a boring tool and open out until 1/8th” (0.125” or 3.175mm) of the outside edge remains, and to a depth of 1/4” (0.250” or 6.35mm).  Set the top slide over to 15° and set the tool to be at 90° to the work. Cut the taper from the contour, towards the turret or faced end. Reset top slide over to 3° and square the tool to 90° to axis. From the other side of the contour, turn the taper back towards the chuck end, until you are 7/32nd (0.2185 or 5.5563mm) from the scribed mark at 1.75” (44.45mm)from faced end. Move the rook blank, still in its chuck, to the vertex on the milling machine or rotary table and centre the mill to the rook’s centre

To make the slots on the top of the rook, use a 1/8th (0.125” or 3.175mm) slot drill and mill 2 slots to a depth of 0.100” or 2.54mm using either the x or y axis (as long as you always use the same axis). Rotate the vertex/rotary table to 60° from your start point. Carry out the next set of slots. Another 60° then cut the last two slots. You should now have six equidistant slots in the rooks head.  Take the chuck holding the rook back to the lathe and polish to finish. Part off to length then polish off the base.
The Bishop

Bishop 2.25” or 57.15mm tall

The Bishop makes a nice change because we do most of the work on the lathe. To start, chuck a piece of 1” (25.4mm) diameter brass or aluminium bar and face the end. Next, measure back 0.9375” (23.8125mm) from the faced end and scribe a mark. Use the contour tool with its centre lined up with the scribed mark and cut in to a depth of 0.100” (2.54mm) for the first part of the contour cut.  Now, set the top slide over to 13° and from the chuck side of the contour just machined, turn the taper until the taper is 15/16th (0.9375” or 23.8125mm) long and the neck diameter is 0.5”dia (12.7mm).

Replace the turning tool with the contour tool and using very light cuts, make the contour match the taper already cut. Now for our third tool change which required to turn the bishops head. Replace the cutter with the ball turning tool, set to cut a 1.25” diameter ball. Find the centre of the top of the bishop blank and turn the bishop’s head to a diameter of 11/16th (0.6875” or 17.4625mm). The last procedure is to remove the bishop with its chuck and take it to the milling machine. Mount the chuck on the vertex and set the angle of the bishop at 50° from the vertical. Use a 1/16th (1.5875mm) slitting saw and cut a slit 0.300” (7.62mm) from the tip of the bishops head, to a depth of 0.300” (7.62mm). Return the chuck with the completed bishop to the lathe for final polishing.

The Queen

Queen 2.45” tall (62.23mm)

To make the queen it’s all lathe work. Start by mounting a 1” (25.4mm) dia bar of brass or aluminium in a 3 jaw chuck. There should be a minimum of 3” (76.2mm) bar clear of the chuck. After facing the end of the bar take a skimming cut for 2.5” (63.5mm) towards the chuck end. Scribe a mark 0.250” (6.35mm) from the faced end and centre the contour tool over the mark. Then take light cuts until the contour is 0.80” (20.32mm) in diameter. Now scribe a further mark at 0.850” (21.59mm) from the faced end of the bar and make small cuts with the contour tool until a finished diameter of 0.840” (21.336mm) is achieved. Now replace the contour tool with a boring bar and set top slide over to 60°. Take small cuts until the top of the queen comes to a point. I made use of the Myford ML10’s reverse feature to carry out this top taper

photo 12 Queens top

Still using the boring bar make a slight cut 0.300 from the centre point of the newly turned top to a depth of 0.050” (1.27mm) to make the ring shown in photo 12.

Remove boring tool and replace it with a cutting tool. The remaining two tapers are next so set the top slide over to 5 ° and make the first  taper cut between the top contour and the middle contour. Continue taking light cuts until the taper matches the two contours. When satisfied set the top slide over to 8° and make the last taper which runs between the middle contour and the base of the Queen.

Finally return top slide to zero ° and change to a parting tool to part off to length of 2.45” (62.23mm).

The King.

King 2.5” tall or 63.5mm

The king is very similar to the queen except that his body is a little fatter and he has a cross at the centre of his head. Start by chucking a section of 1” (25.4mm) diameter bar, taking a light cleaning cut for 2 ¾” (69.85mm). Now face the end of the bar before using a centre drill, followed by drilling and tapping a 3mm hole (or any equivalent i.e. ME or BA).

Measure 0.250” (6.35mm) from the faced end and scribe a mark. Measure another 0.750” (i.e. 1” (25.4mm) from the faced end) and scribe a second mark. Use the contour tool and centre it at the 0.250” (6.35mm) mark and form the first contour,  until it just completes its shape and no deeper. Re position the contour tool centre to the 1” (25.4mm) scribed mark and using light cuts, take the tool in until you have a finished diameter over the contour of 0.8150” (20.701mm)

Change to a boring bar with the top slide set over to 60 ° turn the top as you did with the queen, between first contour and centre hole. Reset the top slide to 10 ° and change the tool so the first taper can be cut between the two contours,  to a depth that matches the contours. Re position the top slide to 6 ° and cut the last taper for the main body until it blends in with the contour and the base. Polish the king and then part off to length.

The last item to make is the cross for the king’s head. The dimensions for the cross are all 1/8th” wide (0.125” or 3.175mm) and a thickness of 1/8th” (0.125” or 3.175mm) and you can either mill or file to shape.(See photo Kings Cross)  The base of the cross is rounded so it can be threaded 3mm. Polish, and then screw the cross into the top of the king. I used a little loctite to ensure it doesn’t go missing in the future.

That concludes the build, and hopefully you now have a nice chess set to create a stir, which hopefully will put off your opponent when playing. It really is nice to feel the difference in weight and the set is certainly tactile.

After thoughts

After polishing I did use a lacquer to protect the polish but I must admit I didn’t get on with it to well. Whether I used the right product or know I don’t know, but there may be better ways to protect your work.

Another variation I have thought of since making the first set is an all aluminium one with one side anodised, but you loose the weight differential, which is one of the nice outcomes of Brass and Aluminium.  Unless of course you drill out the base and put a plug of brass or some other heavy metal in the hole.

Fig 1 Pawn 1.25” tall (31.75mm)
1.    Chuck 3/4” (19.05mm) bar and measure ½” (12.7mm) from faced end
2.    Set top slide over to 20 °
3.    Make sure the top slide has enough travel for taper
4.    Start taper at the ½” (12.7mm) mark and work towards chuck
5.    Cut taper to a length of ¾”(19.05mm) from ½” (12.7mm) mark
6.    Use ball turning tool to turn the ball end of the pawn
7.    Always compare with the master pawn
8.    Always sharpen tools before starting another pawn

Fig 2 Rook 1.75” tall (44.45mm)

1.    Chuck 1” (25.4mm) dia bar with at least 2” (50.8mm) protruding  from the chuck
2.    Face off then lightly scribe a mark 1.75” (44.45mm) from the faced end.
3.    Now turn the blank to 0.8125” (20,6375mm)
4.    ¾” (0.75” or 19.5mm) from the faced end and use the contour tool to depth of  the contour  (0.7928 or 20.1371mm)
5.    Return to the faced end, centre drill then drill out to ½”  (12.7mm) using successive drills and 0.250” (6.35mm) deep.
6.    Use the boring tool to open out to 1/8th” (0.125” or  3.175mm) of the outside edge remaining  and to a depth of  ¼” (0.250” or 6.35mm)
7.    Set the top slide over to 15° and set tool to be at 90 ° to axis.
8.    Cut taper from the contour towards the turret or faced end.
9.    Reset top slide over to 3 ° and square the tool to 90 ° to axis.
10.     From the contour turn the taper back towards the chuck end until you are 7/32nd (0.2185 or 5.5563mm) from the scribed mark at 1.75” (44.45mm) from faced end.
11.      Move the blank,  still in its chuck to the vertex on the milling machine or rotary table and centre the mill to the rook’s centre.
12.     Mill 2 slots to a depth of  0.100” (2.54mm) with 1/8th (0.125” or 3.175mm) slot drill using either the x or y axis (as long as you always use the same axis).
13.    Rotate the vertex/rotary table to 60 ° from your start point.
14.     Carry out the next set of slots.
15.     Another 60 ° then cut the last two slots. You should now have six equidistant slots in the rooks head.
16.     Take the chuck back to the lathe and polish to finish.
17.    Part off to length then polish off the base.

Fig 3 Knight 2” tall (50.8mm)

1.    Chuck a 1” (25.4mm) dia bar with at least 3” (76.2mm)  clear of the chuck.
2.    Face the end and take a light cleaning cut for a length of a minimum of 2” (50.88mm) and lightly scribe a centre line on the faced end using a tool with the lathe.
3.    This completes the lathe work, which forms the Knight blank as the main work  is done on the milling machine.
4.    With the blank in the chuck place on vertex parallel to the table.
5.    Mill down to 5/16th (0.3125 or 7.9375mm) for length of 1.5” (38.1mm) from the faced end or the head.
6.    Now turn through 180 ° and repeat above.
7.    Set vertex and blank at 45 ° to cut base shoulder and mill down until you meet the head joint turn through 180 ° and repeat the cut to the head joint.
8.    This completes the first stage of creating the knight blank.  What follows now are cuts, working with the head now set parallel to the table.
General rotary table notes for the knight chess piece.
Use angle gauge to ensure blank is parallel to table (photo 8) and the first section deals with the jaw side of the piece.
1.    Zero the rotary table dial to match 0 when blank is in line to X axis. Now rotate the table clockwise 5 ° (for the shape of the ear).
2.    Position the cutter’s left hand edge to the right of the scribed centre line.
3.    Move the y axis out for 0.0750” (1.905mm) then move x axis to touch the cutter to the edge of the blank. At this position zero the DRO’s if you have them, or the dials if not.
4.    Using the x axis mill for a distance of 0.138” (3.5052mm) taking light cuts until through.
5.    Move the table a further 40 ° clockwise. It should now be 45 ° from the start position.
6.    Mill using the y axis for a distance of 0.460” (11.684mm) (out from column) or cut completely to the edge of the blank.
7.    If you have milled through to the edge reposition the cutter so it cuts from the 0.460” (11.684mm) point on the y axis.
8.    Without changing the rotary table settings now use the x axis and mill for a distance of 0.430” (10.922mm)  (this is the width of the jaw)
9.    Again without moving the rotary table settings use the y axis into the blank for a distance of 0.200” (5.08mm).
10.    From this position again using the y axis now mill until you reach the outside of the piece.
11.    Reset the rotary table to 0 ° then 20 °  anticlockwise and the start position of the final cut is located 0.4” (10.16mm) from the inner most position of the lower jaw.
12.    From this start position now use the x axis and mill from the neck out to the outside of the knight blank. This completes the first side.

Second phase the back profile of the knight.

1.    Reset the rotary table to the 0 position.
2.    Now turn the rotary table clockwise for 5 °.
3.    Align the inside edge (nearest pillar) of the cutter with the centre mark.
4.    Move the y towards the mill for 0.075” (1.905mm).
5.    From this start position mill on x axis for 0.125” (3.175mm) towards the chuck or base of knight.
6.    Now set the rotary table to 45 ° clockwise from the zero position and place the cutter at the finish position of the last cut.
7.    Use the x axis for a distance of 0.320” (8.125mm) towards the chuck or bottom of the knight.
8.    Reset the rotary table to 0 ° then from this position set it to 15 ° clockwise from zero and from previous end position mill using the x axis to the outside edge.
This completes phase two of the knight.

The final cuts are for the eye and mouth.

1.    Zero the rotary table.
2.    Position the centre of the cutter over the centre line of the blank
3.    Move the x axis from left to right 0.340” (8.636mm) from the ears.
4.    Now move the y axis out 0.085” (2.159mm).
5.    Plunge the cutter in to a depth of 0.010” (0.254mm).
6.    Reset the rotary table to start position at 0.
7.    Turn the table 45 ° clockwise.
8.    Position the cutter at the centre of the jaw.
9.    Move the y axis from in for a distance of  0.142” (3.6068mm) and a depth of 0.010”(0.245mm).
This completes the knight.

Bishop  2.25” tall (57.15mm)

1.    Chuck a piece of 1” (25.4mm) diameter brass or aluminium face end.
2.    Measure back 0.9375” (23.8125mm) and using  the contour tool cut in to a depth of 0.100” (2.54mm) for the first cut.
3.    From the chuck side of the contour set the top slide over to 13 °  and turn the taper until the taper is 15/16th  (0.9375” or 23.8125mm) long and the neck diameter is 0.5”dia(12.7mm)
4.    Replace cutter with the contour tool and make the contour match the taper already cut.
5.    Replace cutter with the ball turning tool set to cut a 1.25” ball. Turn the bishops head to a diameter of 11/16th (0.6875” or 17.4625mm).
6.    Keeping the nearly completed bishop in the chuck take it to the vertex and set the angle at 50 °.
7.    Using a 1/16th  (1.5875mm) slitting saw cut a slit 0.300” (7.62mm) from the tip of the bishops head to a depth of 0.300” (7.62mm).
8.    Take back to the lathe and polish to finish.

Queen 2.45” tall (62.23mm)
1.    Using a 3 Jaw chuck (3jc) mount a 1” (25.4mm) dia bar of brass or aluminium with a minimum of 3” (76.2mm) long clear of the chuck.
2.    Face the end off and take a skimming cut for 2.5” (63.5mm).
3.    Centre the contour tool with the faced off end, measure back 0.250” (6.35mm) and then make small cuts until the contour is 0.80” (20.32mm) in diameter.
4.    Move the tool towards the chuck by 0.600” (15.24mm) A total of 0.850” (21.59mm) from the faced end.
5.    Make small cuts with the contour tool until a finished diameter of 0.840” (21.336mm).
6.    Replace contour tool with a boring bar and set top slide over to 60 °.
7.    Take small cuts until the top of the queen comes to a point. ( I ran mine in reverse to achieve this task).
8.    Make a slight cut 0.300” (7.62mm) from the centre and make the ring as per photo to a depth of 0.050” (1.27mm).
9.    Remove boring tool and replace with cutting tool.
10.    Set the top slide over to 5 ° and make the taper cut between the top contour and the middle contour.  Continue until the depth matches the two contours.
11.    Set the top slide over to 8 ° and make the last taper between the middle contour and the base of the piece.
12.    Return top slide to zero °.  Use this opportunity to polish the queen.
13.    Part off to length of 2.45” (62.23mm).

King 2.5” tall (63.5mm)
1.    Chuck a section of 1” (25.4mm) diameter bar and take a light cleaning up cut.
2.    Face, centre drill, then drill and tap a 3mm hole (or any equivalent i.e. ME or BA).
3.    Use contour tool and centre it at the faced end edge.  Measure towards the chuck 0.250” (6,35mm) and form the first contour so that it just completes its shape and no deeper.
4.    Re-position the contour tool centre to 1” (25.4mm) from the faced end and using light cuts take the tool in until you have a finished diameter over the contour of 0.8150” (20.701mm).
5.    Re-position centre of contour tool 0.75” (19.05mm) from faced end and advance it into the work for 0.150” (3.81mm).
6.    Change to ordinary turning tool and set top slide over 10 °. Turn a taper between the two contours.
7.    Re-position the top slide to 60 ° and turn between first contour and centre hole forming the topmost taper of the king.
8.    Re-position the top slide to 6 ° and cut the main body taper until it blends in with the contour base.
9.    Polish the king and then part off to length.
10.    Make the cross so the body parts are 1/8th (0.125” or 3.175mm) and a thickness of 1/8th (0.125” or 3.175mm).
11.    Bottom of cross is ¼” long and rounded so it can be threaded to match hole (3mm in my case).
12.    Polish and screw the cross into the top of the king.  I also used a little loctite to ensure it doesn’t go missing.

Filed Under: Readers Projects Tagged With:

Myford ML 10 Lathe Turning Project Chess Set (Section 1)

11/11/2010 By Leave a Comment

Readers article supplied by Mike Freeman of Mikes Models Model Engineering Website on his use of a Myford ML10 to create a brass and aluminium chess set  in his workshop.

Trying to combine hobbies is always a productive thing to do in my mind. As a novice model engineer I wanted a project that would teach me new skills in using the lathe, and the milling machine. I have always believed that repetition enhances quality, and if I made a chess set, not only would I learn how to turn tapers, ball shapes, and some profiling but I would also have to produce like items, to the same standard. After all there are 32 pieces to make.
After deciding to make the chess set my first task was to design the pieces, and decide what size each piece should be. I used a small wooden chess set I had to set the ratios between the pieces. Then I looked at various chess boards for the square size, finally arriving at the height and diameter of each chess man (and Queen). When the set was complete, I intended to present it to my younger brother on his retirement from the Police force. So I wanted to make it to the best standard that I could.
I decided to use brass and aluminum for the chess men because I wanted a set that not only would be very tactile, but also the finish would be distinct in regards to both sides or ‘black and white’. I also liked the idea of heavy and light pieces when playing, as you would get used to moving your own men, but when taking an opponent’s piece, there would be an additional experience of either a heavy, or light chess piece. Because of these weight differences there may be a benefit for blind, or partially sighted players.
The next stage was to get some drawings done and once the basic shapes were sketched out I then worked out how to machine them. However, before too much time was invested, I thought I would try and make a pawn as a practice piece since it required both taper turning and a ball shape for its head.

the pawn.
As neither turning balls, nor tapers are something I had done before or even knew how to do, it was into the books, magazines, and a search on the internet, to find out how you did both tasks.
Ball turning tool:
I found two or three different methods to turn balls on the internet (no doubt there are many more) and these varied between using a form tool, and making a tool specifically for the task.
Since the some pieces required a large ball I discounted a form tool and decided to make a special ball turning tool. This would allow me to have a tool for future use, and have the flexibility of turning different diameters in the future. Additionally since there were 16 pawns and 4 bishops to make with different radii, it made sense to invest the time to make the tool.
Once I decided to make the special tool the next decision was which one? In the end the final design choice came down to what materials I had at hand, so I went for the design shown in photo 2.

ball turning tool
Bearing in mind my experience level at that time, making this tool was a major undertaking in its own right but I must say I was quite pleased with the results, whilst not exhibition standard, I made a tool that turned balls of variable sizes, and to a fine finish. So, armed with the tool to turn the ball shaped heads, I then focused on how to turn tapers? It was then that I discovered that the top slide actually moves around! My only lathe at this time was a small Myford ML10 and having located the two bolts on the cross slide; I loosened them, and swung the slide to a variety of settings. I made several cuts at different degrees of turning the top slide until I found the angle I liked the best.
This simple task of taper turning to the experienced model engineer may seem so simple, but to me the results were most satisfying. I now had the basics information and tools required for my Pawn design. So the next task was to decide how to machine the pawn itself. Since there were 16 pawns to make I thought that some form of aide memoir

fig 1 

would be useful, and so it proved to be.
When my first pawn was completed and I marked it underneath as the master pawn. This would allow comparison against a set standard.
Metal turning at last – the first pawn.
Pawn 1 ¼” tall (31.75mm)
I used aluminum for the first pawn, since I found it easier to turn at that time, and I had several 3/4” (0.750” or 19.05mm) diameter bars in stock.
To make a pawn first put a length of ¾” (19.05mm) diameter bar into the 3 jaw chuck, leaving about 3” (76.2mm)showing.
After facing the end of the bar, measure back 0.500” (12.7mm) from the faced end. I used a pair of dividers set to ½” for marking the bar. The front ½” will be left for the moment and will be for the pawns head. From the ½” mark measure back towards the chuck another ¾” (or mark from the faced end back a total of 1 ¼”(1.250”)). There should now be two guide lines as shown in

a pawn blank with two marks

Set the top slide over to cut a 20° taper between the two marks. The method I used when cutting the taper was to take very light cuts, moving from the chuck towards the faced end and finishing the cut at the ½” mark. Then moving the cross slide back towards the chuck and start again, continuing to cut the taper until it meets the back mark.

pawn with taper cut

Next change the cutting tool for the ball turning tool. The radius for the tool to cut is 5/16th” (0.3125 or 7.9375mm) and light cuts are required to turn the ball. Continue forming the ball until it meets the taper neck. It may be required to take a further light cut or two of the taper until the neck and the head blend together. The pawn now only requires a base of the original diameter left for 1/8th” (0.125” or 3.175mm) where it should be parted off , however I took the opportunity of the pawn being held securely, to polish it with metal polish impregnated cloth. This can be found in many large supermarkets. I protected the lathe bed when ever polishing, using kitchen paper roll held in place with small magnets. It always surprises me how well aluminum polishes up, and how quickly it dulls again! When satisfied with the finish, part off 0.125” (3.175mm) from the end of the taper. This completes the machining and hopefully there is now the first pawn, looking something like the pawn in photo 5

cutting the knight body parallel

 Only another 15 to go!
I was pleased with the first attempt at the pawn, but thought that if the chess set had any chance of completion, I would need to be able to make, what I considered to be the most complicated piece, the Knight. I didn’t want to proceed with the next 15 pawns only to find I couldn’t produce a good enough knight, and it did prove to be the most demanding machining I had yet done.

Since I was breaking new ground with the chess set, I had to produce each piece one after another, to check the feasibility of the design, and machining methodology. However, if you consider making this set, I would suggest that the pawns be tackled in one go. I believe you achieve a better common standard when making a large batch. The size of the chess men and the machining procedures are now known, which should make it is easier to work in batches.
 

The Knight.


Knight 2” tall (50.8mm) The first task is to produce a knight blank on the lathe, before moving onto the ‘interesting’ work on the milling machine. If you do not have a milling machine I am sure it would be possible to achieve a nice knight with filing. You start by placing 1” diameter (25.4mm) aluminum or brass bar in the chuck, with 2 ½” (63.5mm) showing. Face the end of the bar and then take a light cleaning cut for 2” towards the chuck. With the lathe stopped and using the cross slide, mark a line on the faced end across its diameter. This mark will be used later on the milling machine. It’s not possible to use a large length of bar with my method as the chuck needs to transfer to the Vertex

cutting the taper on the knight base

with the blank, for part of its operation. Still holding the knight blank, transfer to the transfer to the milling machine and when setting up the vertex it is important that it is secured square to the milling table. With the blank held parallel to the table and the end of the end mill, or slot drill, just touching the blank, set the z axis digital readout (DRO) to zero. The next task is to mill down for 5/16th” (0.3125 or 7.9375mm) for of 1 ½” (38.1mm) from the faced end towards the chuck. The Vertex is then revolved 180° and the second sided is milled the same as the first.
The next stage is to cut the 45° base shoulder tapers. To do this the vertex is adjusted to a 45° angle and careful cuts are made until the top of the taper meets the main body. The Vertex is then revolved a further 180° and the second cut is made. The blank should now look something like photo 7

(photo of blank with both shoulder tapers cut).
The blank is now removed from the chuck and the challenging part started, which was the work on profiling the knight’s body. I found it useful to draw the approximate shape of the body on each side of the blank, in permanent marker pen. This helped with orientation and which cut was required. It makes it a lot easier to follow what needs milling, and confirms you have got the angles right. The Vertex is now removed to be replaced by a rotary table, which is again set square to the milling table. A fixture to hold the knight blank onto a rotary table is required and little on how I made the fixture may be helpful. My fixture had two main parts, the base and the holding bar, which is secured by two screws. These apply pressure on the knight’s base and therefore secure it in place.
The dimensions for the aluminum base are 2” (50.8mm) by 1.5” (38.1mm) by ¾” (19.05mm). The steel holding bar is made from 2” (50.8mm) by ¾” (19.05mm) by ¼” (6.35mm) bar. The base was made by holding the squared off aluminum blank against a large angle plate on the milling machine and the cut out was bored to 1” (25.4mm) diameter and a depth of 5/16th” (7.9375mm). The holding bar also has a 1” (25.4mm) diameter recess bored into it to a depth of 1/16th”(1.651mm). The base was then placed in a vice and a 3/16” (4.7625mm) wide and 3/16” (4.7625mm) deep slot milled around the 4 sides, to allow clamps to be used to hold it onto the rotary table. Two 6mm holes are tapped in the centre of the aluminum base for the securing bolts.

fig 2

Once the rotary table was set square to the milling table and centred under the quill, all DRO’s were zeroed. The knight blank should be positioned on the holding fixture so that the blank is at 90 ° to the Y axis. To ensure the body of the knight was parallel to the milling table I used a digital angle meter. First the angle meter was zeroed on the milling table and then put onto the knight blank, adjusting the blank until the meter read zero.

knight holding fixture for the rotary table

The fitting of DRO’s to my milling machine has proved invaluable and I would recommend the expense to any novice engineer with a milling machine. To aide in machining the profile I used a diagram [fig 3 direction of profile cuts for knight] to show the direction of cuts. A 1/8th “(3.175mm) slot drill was used to make all the cuts which were kept light. This helped to ensure mistake were minimised.

Knight profiling procedure


Set the rotary table dial to match 0 when blank is in line to X axis. Now rotate the table clockwise 5° (for the shape of the ear) and position the cutter’s left hand edge to the right of the scribed centre line made on the lathe. Move the y axis out for 0.0750” (1.905mm) then move x axis to touch the cutter to the edge of the blank. At this position zero the DRO,s if you have them or the dials if not. Using the x axis mill for a distance of 0.138” (3.5052mm) taking light cuts until through

fig 3

 (cut A on fig 3).

Move the table a further 40 ° clockwise (It should now be 45° from the start position) and using the y axis, cut for a distance of 0.460” or 11.684mm (out from column) or cut completely to the edge of the blank (cut B fig 3) if you so wish.

If milling to the edge, then reposition the cutting tool so it cuts from the 0.460” (11.684mm) point on the y axis. Without changing the rotary table settings now use the x axis and mill for a distance of 0.430” or 10.922mm (cut C fig 3.) This is the width of the jaw.

Without moving the rotary table settings, use the y axis and cut into the blank for a distance of 0.200” or 5.08mm (cut D fig 3.). From this end position again using the y axis now mill until you reach the outside of the piece (cut E fig 3.).

Reset the rotary table to 0° then reposition it 20 ° anticlockwise and the start position of the final cut is located 0.4” or 10.16mm from the inner most position of the lower jaw, position X on the diagram, fig 3. From this start position, use the x axis and mill from the neck, out to the outside of the knight blank (cut F fig 3.) . This completes the first sides profile of the knight and it should look something like photo x.

The second phase is to cut the back profile of the knight. Reset the rotary table to the 0 position and turn the rotary table clockwise for 5° aligning the inside edge (nearest mill column) of the cutter with the centre mark. Move the y axis towards the mill for 0.075” or 1.905mm and from this start position, mill on x axis for 0.125” or 3.175mm towards the base of knight (cut G fig 3).

Now set the rotary table to 45° clockwise from the zero position and place the cutter at the finish position of the last cut. Use the x axis for a distance of 0.320” or 8.125mm towards the chuck or base of the knight (cut H fig 3.).

Reset the rotary table to the 0 ° position, then set it to 15° clockwise. Centre the milling cutter from the previous end position, mill using the x axis to the outside edge (cut c fig x.). This completes phase two of the knight and it should now resemble

centering the fixture on the rotary table

The final cuts are for the eye and mouth. Zero the rotary table and position the centre of the cutter over the centre line of the blank. Move the x axis from left to right 0.340” or 8.636mm from the ears and move the y axis out 0.085” or 2.159mm. Plunge the cutter in to a depth of 0.010” or 0.254mm.

Reset the rotary table to start position at 0 and turn the rotary table 45° clockwise. Position the cutter at the centre of the jaw and move the y axis from in for a distance of 0.142” or 3.6068mm and cutting to a depth of 0.010” or 0.245mm.

After this marathon hopefully you will see the finished results shown in photo 10.

digital angle meter used to set the knight blank

All that remains now is to clean up the machines, mark with a file, then polish. Oh and just make the other three.

To be continued

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