|LaymarCrafts Woodturning||Hints & Tips|
|Multi Function Baseboard, Sled and Carriers Pt. IV|
In the final part of this article I detail the various ways I used for Pivoting, Guiding and Fixing the Sled in position for its various applications.
I have found the concept to be very flexible in both design and use and that most eventualities are covered within the design and should new requirements be needed then these are easily made based on the basic concept.
Like all the Items described here you will have your own ideas born out of Need and Available Materials, they do not have to be made all together, choose those that you think you will need and add others later.
All Fixtures are based on the 46mm Centres I used for the Baseboard Fixings.
Screwed Adjusting Bar
The Screwed Adjusting Bar was designed to give an infinitely adjustable Pivot or Fixed Point for the Sled, although I find that it is perhaps used less now as I have refined my needs and tend to use the Fixed Pivot Points described later.
The Screwed Adjusting Bar comprises of two Support Blocks, a length of Screwed Rod and a Pivot Block plus various Nuts and Washers.
I had two Aluminum Blocks which happened to have a Ball Race fitted in the middle of the block, although not essential there is an advantage in having such an arrangement.
However any suitable Block of Hardwood or Metal will be adequate as there are no real Stresses or Strains on the assembly when in use, into the Block you need to Drill 2 x 7mm Holes at 46mm centers as shown above.
Because the Ball Races had a 10mm Central Hole I chose to use a length of M10 Screwed Rod as this fitted in well with the overall design.
In the sketch above you can see the Block at one end of the Screwed Rod as fixed to the Baseboard, the Block at the other end will be identical.
The Screwed Rod is located and Locked by the Nuts and Washers at either side of the Block, this needs to be just loose enough to allow easy rotation and fixed either with some Thread Lock to prevent the nuts from undoing when in use or by using a Locking Nut.
The Long Nut on the end of the Screwed Rod is for adjusting the Position of the Pivot Plate, I use a Suitable Socket mounted on a Square Drive in my Battery Drill to move the Pivot Plate up and down the Screwed Rod.
This leaves the Pivot Plate which is formed from a piece of Steel approximately 135mm x 70mm and 10mm thick onto which is welded a M10 Long Nut.
The Dimension "H" now fixes the position of the Horizontal Hole in the two Blocks above.
To the left of the Long Nut there is a 7mm wide slot and this is used to lock the Pivot Plate in place, once set in the correct position for use, using a M6 Screw into the most convenient Insert in the Baseboard.
I then drilled and tapped 12 x M6 Holes in the Plate with the 3 middle Holes on the Plate Center Line for operations where the Sled is to be Pivoted about a Center Point, i.e. Ball Cutting etc. and the other Holes are for Fixed Use such as Index Drilling.
You will need to be aware of the position of the Holes in the Pivot Plate in relation to the use of the Pivot and Sled on the Center Line of the Lathe for the Ball Jig Set up and, in all positions, to make sure the Sled does not foul the Adjusting Screw when swung through 90°.
In the sketch above I show the principle of the set up with the Sled and Pivot Bar attached to the Adjustable Pivot Block this position would be used for Decorative Fluting to the underside of a Bowl or for Drilling into Pots/Vessels in combination with the Indexing Head on the Lathe.
This Screwed Rod Assembly once made and adjusted can be removed from the Baseboard as a complete assembly and stored away when not in use, likewise it can be positioned along any of the edges of the board or in any intermediate point on the board.
This Sketch shows the typical position used for Ball Cutting.
Fixed Pivot Point
Adjustable Pivot Point gives you Flexibility but a Fixed Pivot Point is
useful and in many cases all that is required.
I have a number for various situations but they are all generally based around the Sketch on the left.
I firstly sourced a 25mm Ø x 10mm Disc of Brass, but any suitable material will do, into this I drilled a 5mm Ø Hole and tapped it to suit a M6 Length of Screwed Rod or a Bolt with the Head Cut off.
You will need to fix this and I carefully Silver Soldered the Screwed Rod into the Disc I suggest you Silver Solder only from the Top so as not to get any Solder in the lower thread.
As a precaution I also Filed two Flats, opposite each other, on the Disc so if necessary I could undo the Pivot Point with a Spanner should it become locked in any of the Baseboard Inserts.
The dimensions in the Sketch are not critical although the thickness of the Disc needs to be similar to the thickness of the Adjustable Pivot Point which is determined by the position of the Pivot Bar in the Sled.
An alternative would be to have just a Pivot Plate generally as described above but minus the Long Nut for the Screwed Rod, this could be used to place the Pivot Point anywhere on the Base Board relative to a Screwed Insert and you should be able to achieve Infinite Adjustment of Position.
Copying Guide Blocks
Copy Turning is not something I have done, but I did include for the possibility in my design, for both the Sled, and the Support of a Template if the need should arise.
The basic components are two Support Blocks and two Attachment Plates for supporting the Template which can be made from any Material such as MDF, Tufnol or Metal to suit your needs.
For the Support Blocks I used two 70mm lengths of 25mm x 37.5mm Box Section into which I welded a length of Mild Steel to enable the row of Holes in the Top to be Tapped.
The Fixing will again be determined by your chosen Fixture Pitch on the Baseboard [46mm] and these Holes are purposely located by the two outer Holes at the top so that I can pass an Allen Key through into the Cap Head Screws used for fixing to the Baseboard.
The Attachment Plates, shown right, are made from 3mm Steel and are the means of attaching the Guide/Template to the Support Blocks and at the same time allowing for a reasonable amount of adjustment to the position of the Guide/Template.
For "One Off" requirements where perhaps a Special Attachment Plate is required then these could easily be made from MDF or Ply.
When using the Drill Jig it is necessary to clamp the Sled in position on the Baseboard for stability and accuracy in use, for this I drilled two additional holes in the Sled for the adjustment rods as seen in the picture below.
The Locking Bracket is also clamped via a suitable Screwed Insert in the same way as the Pivot Plate, with the Slot in the Locking Bracket it is possible to locate onto a Screwed Insert regardless of the position of the Drill Jig.
The Locking Bracket is made from a piece of 30mm x 30mm MS Angle and this is the same length as the width of the Sled, 134mm you need to drill 2 x 9mm Ø holes in one flange of the Angle to match the two holes in the Sled.
In the other flange you will require a 7mm wide Slot for the Clamping Screw and this needs to be at least 92mm long as shown above.
To connect the Locking Bracket to the Sled I used 2 x 380mm lengths of M8 Screwed Rod, the length of rod is determined by the length of the Sled, the position of the Drill in the Jig and the furthest Screwed Insert from the Jig when in use, although too long is not a problem, being too short could mean limited use of the set up.
Part I of this Article.
Part II of this Article.
Part III of this Article.
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Last update 06 May 2008
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