|LaymarCrafts Woodturning||Hints & Tips|
|Belt Sander Modifications and Jigs Pt. I|
The typical Belt Sander like Bench Grinders are nearly always fitted with an inadequate Stop/Rest particularly if used for heavy use in the Vertical Mode and when used for Tool Sharpening.
I find that the Belt Sander is a versatile machine for not only the obvious use of Sanding and Shaping Wood but I use it for shaping all forms of Metal, Plastics as well as for Sharpening various Tools and Twist Drills.
All these operations I can accommodate on my basic Belt Sander simply by upgrading the the main rest and adding an adjustable rest plus a support angle for the Drill Sharpening Jig as detailed below.
General Purpose Rest/Platform
The general purpose Rest was just a means of "Beefing Up" the unstable flimsy bent metal stop/rest supplied as part of the machine.
retained the original rest and used it as the fixed point for the new
Rest, for this I used a length of 50mm x 50mm x 6mm [2" x 2" x
¼"] Aluminum Angle and attached it to the existing rest with two
M6 Counter sunk Screws.
For this I drilled and tapped the Aluminum Angle and ground back the Screws so they were flush with the top of the new Rest.
The Top was then covered with a piece of Formica stuck to the angle .
To give a very stable Rest I added a Tie Bolt at the opposite end of the Rest, this has to be easily removable to allow the replacement of the Belt.
This is constructed from
a M6 Screw which passes through a Angle Support Bracket bolted to the Belt
Sander Body, to ensure that when tightening the Bolt you do not pull the Rest
into the Belt.
I have used a piece of Steel Tube, cut to the precise length required, through which the Bolt passes.
The Picture right clearly shows how this goes together and I can assure you it is as steady as a rock.
You will see two Holes in the front face of the Rest, these are for attaching various bolt on items such as the Drill Sharpening Jig described later.
I have made numerous Guides and Jigs that sit/slide on the Rest to give 90° and 45° Angles, some of these are detailed below and in Part II.
The Angle Rest/Platform was born out of a desire to use the Belt Sander as a means of Sharpening Tools at a relatively low speed, as this would give me a Flat Grind, in particular on Scrapers and Parting Tools, plus the added advantage of a low speed and therefore a Cooler Cut.
The Table below compares the the relative Grinding Speeds for the various types of Grinder in general use [all based on a 50Hz Power Supply, multiply figures by 1.2 for 60Hz Supply].
|Grinder Type||Bench HS||Bench HS||Bench LS||Bench LS||Tormek||Tormek||Belt Sander|
|Wheel Diameter||6"||8"||6"||8"||8"||10"||4" x 36"|
|Nominal Motor Speed||2800rpm||2800rpm||1450rpm||1450rpm||120rpm||90rpm||1425rpm|
|Grinding Surface Speed||4400fpm||5800fpm||2240fpm||2950fpm||250fpm||235fpm||750fpm|
The Normal High Speed [HS] Bench Grinder, as you would expect achieves the highest Grinding Surface Speed [in Feet per Minute, fpm] depending on Wheel Size, the so called Low Speed Bench Grinder is in fact approximately half the High Speed Ratings by virtue of these using a 4 Pole Motor in place of the normal 2 Pole Motor.
At the other end of the spectrum we have the Tormek Wet Grinders which operate with a very Low Grinding Surface Speed, and in between we have the Belt Sander which gives a Speed approximately a third lower than the Slow Speed Bench Grinder.
picture shows the principle of the design for the Tilting Rest/Platform
which was made from Shop Off Cuts.
The Platform itself is made from a 4mm [3/16"] piece of Aluminum with a bracket attached via two M6 [¼"] Countersunk Screws.
The top of the Platform is covered with a piece of Formica for smoothness in use and to cover over the screws.
The two side bars, which are attached to the main frame of the Belt Sander are pivoting on a length of Screwed Rod [M6] which is tack welded into the platform bracket via the two M6 Nuts.
Angle adjustment is achieved by slacking of the two M6 Nuts, positioning the Platform and re-tightening the Nuts.
The side bars are slotted to allow for forward/back adjustment to ensure that a safe working gap is maintained between the leading edge of the Platform and the Belt.
The fixing/adjustment is by way of two M8 [⅜"] Screws, these are screwed into a matching Nut inside the Belt Sander Frame and Tack Welded in place, i.e. retained Nut principle.
The Platform is 125mm x 60mm [5" x 2½"],
but as each Belt Sander is different you will need to adjust these
dimensions to suit your particular machine.
I show examples of the Grind Quality achieved, left on the Richard Raffan
Style Scraper and right, on a ¾" Round Side Cut Scraper.
These are straight off the Belt Sander and there is no Colouring to the Grind Edge and therefore the Temper is preserved.
The Grind is Flat, not Concave as you would normally get with the Bench Grinder.
Two more examples of the Grind achieved on a ¾" Roughing Out Gouge and the½" Rance Style Box Scraper.
Equally impressive results are
achieved with my array of Parting Tools, Scrapers and Tipped Tools using
either the Platform or the Vee Holder.
Twist Drill Sharpening Jig Support
Like many of us I have accumulated various "Goodies" over the years and never really used them, so when I was playing around with this little project I saw an opportunity to accommodate my Twist Drill Grinding Jig and therefore start sharpening my drills more regularly and correctly.
All that was required was a short length of the 50mm x 50mm x 6mm [2" x 2" x ¼"] Aluminum Angle used for the main Rest, this is bolted onto the Rest with two M8 Bolts.
To fix the Jig Base I drilled a 9mm Hole, for the M8 Fixing Bolt required for the Base, in the top of the Angle, this needs to be as far forward as necessary to allow for positioning of the Jig.
In fact I ended up with the Hole so close to the other flange of the Angle that I had to grind the Bolt Head down to enable me to get it in the hole.
There was a benefit, the Bolt could not turn when tightening the Adjustment Lever so the operation became a one handed job.
The set up can be clearly seen in the picture and I find it easy to use and manipulate, far easier than when it was used with the Bench Grinder and mounted to Sharpen on the side of the Grinding Wheel.
Part II of this Article
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Last update 06 May 2008
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