|LaymarCrafts Woodturning||Hints & Tips|
|Mini Bench Power Sander|
There are a number of items that are Turned in the Chuck, and then Parted off, such as Pots, Weed Vases, Candlesticks, Ring Stands etc. etc. The bottom or base of these items have to be finished off before being sealed, every one of us has a different method using a combination Chisels to remove the "Pip" followed by Sanding.
I first saw the use of the 50mm Mini Sanding Discs (Velcro Fixing Type) for this purpose at a Turning Demonstration. The person in question after parting off the piece used such a Disc in a Power Drill to remove the relatively rough surface caused by the Parting Tool to give a smooth finish.
I tried this method but found it difficult to control particularly with small items, such as a Weed Pots, in one hand and a Black & Decker Drill in the other. The problem I found was that these smaller items were too slippery, due to the Polished Finish, to get a reasonable grip on and that the Drill was not well balanced for operation with just one hand.
A visit to a Car Boot Sale (always a good source of odds and ends) provided me with a small 6" Bench Grinder for £4, and immediately realised that I had the basis for a solution to my problem.
Firstly the Grinder was stripped of Grinding Wheels, Guards and End Covers as these would now be obsolete for what I had in mind.
You must at this point decide which end you are going to attach the Disc to, although as a Grinder the Grinding Wheels rotate in the same direction (towards you) when viewed end on the LH Wheel rotates in a Clockwise Direction and the RH Wheel in an Anti-Clockwise Direction. I in fact used the Left Hand end of the Shaft.
To attach the Sanding Disc Holder you will need to carefully drill a Hole in the end off the Motor Shaft of the Grinder to suit the Diameter of the Spindle of the 50mm Sanding Disc, in my case the spindle is ¼"Ø (6mm) and I used a 5/16"Ø (8mm) Drill, and to a depth equal to at least half of the Spindle length.
You then simply Glue the Spindle into the Hole using Superglue or Epoxy and you have the perfect solution for Sanding Smooth the bottom of any Turned item.
The principle of operation is simple, holding the Turned Item in both hands you present the base to the spinning Mini Disc and smooth off the base to suit.
By applying the Piece at different angles you control both the amount of Material removed and the area in contact with the abrasive.
If you apply too much pressure you will find that you will stop the Motor very easily and this becomes a useful safety devise as it will prevent you from removing too much material in one spot.
I have been using this set up for over 4 years and I have not yet had a need to replace the Sanding Disc Holder but should I need to do so you only require to gently heat up the Motor Spindle and the Superglue/Epoxy should give way and you can therefore easily remove the worn out Holder if the need arises.
If required you could repeat the exercise at
the other end and use a smaller or larger Disc to suit your needs, you may need
to mount the Grinder on a swivel base so easy access to either end is possible
and also remember the reverse rotation of the Disc.
article is in fact mounted upside down for two reasons:
1) To the original Foot Mount of the Grinder I attached a wooden base with a rubber mat stuck to it and this became a handy area for standing things on.
2) This arrangement shields the on/off Switch from any Dust, this had previously been a problem penetrating and fouling up the Switch and this required regular cleaning.
Finally I fitted a Cover Plate over the recess, which accommodated the Original Grinding Wheel, for no other reason than to make it look better.
After something like 5 years of constant use the original Disc Holder finally gave up and needed replacing and as I had now changed over to using Disc Holders with a Hexagonal Spindle which I found useful in as much as they could be used with the Quick Release Chucks used on Electric Drives for swapping between Drill and Screw Driver.
I decided that if I now fitted one of the Hexagon Drive Units to the Motor Shaft I would have the capability of easily choosing which Grit I used, although I dedicated two Mini Discs by cutting the Shaft Length down it would be possible to use with the standard length shafts although there can be a loss of control in use.
As I already had a Hole in the end of the Shaft it was easy to open this up to suit the Hexagon Spindle of the Holder and simply Epoxy it in place.
I also now have the facility enabling me to use
certain other Fixtures such as small Polishing Mops, Flapper Wheels and Wire
Brushes all of which are now available with Hexagonal Drive Spindles.
Pic 1-The Hexagonal Tool Holder ~ Pic 2 - Shortened Disc Spindle ~ Pic 3 - In Place and ready to go
Mini Disc Storage Rack
I use the 50mm (2") Mini Disc System for finishing Bowls and Platters and I have invested in a Mini Disc Pad for each of the Grades of Abrasive I use as I found that I was getting through too many Discs and Holders and I put this down to the constant changing of Discs as you worked through the Grades of Abrasives, especially as the Pad became Hot with no real time to cool down and this made the Adhesive Joint between the Foam Rubber Base and the Velcro weak and therefore susceptible to parting from the Foam Base.
So I have ended up with 5 Disc Holders which are marked, using a Soldering Iron on the Plastic Base, 1 to 5 to match the various Grades of Abrasive Disc, i.e. 1 = 120g 2 = 180g etc. so I can always see which Grit Size is fitted to which of the Bases.
The Discs are Stored in a simple rack made from a piece of MDF screwed to the wall of the Shed, into this I have screwed 5 Allen Screws with the same size Hexagon as that of the Pads.
Each hole for the Grub Screws used should be just smaller than the diameter of the screw, remember they only have to be a friction fit, if the hole is to small you will delaminate the MDF, try on a scrap piece first to get the correct size and fit, you can always add a drop of Superglue if necessary
For the 50mm [ 2"] Pads the holes need to be at least 60mm [2¼"] apart.
Each Pad will sit snuggly in each of the Grub Screws ready for use.
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Last update 19 July 2007
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