Drill Guard Clamp

The original pillar drill guard clamp made of plastic broke due to a stress fracture close to the tensioning screw along a point of reduced material and was not designed to be removed without removing the chuck. Therefore cutting with a hacksaw was employed to remove it completely.

This a redesign of the clamp to fix the issues, due to the demise of the original clamp and the desire to make the task of maintainence and cleaning of the drill and surroundings easy. Negating the requirement to remove the chuck.

The original with a clamping hole diameter of 40mm was made of a single piece whilst the redesign will compose three pieces. Designed to suit a WorkZone Model: ZJ4116QM/93896 bench drill.

This clamp was designed using Tinkercad Codeblocks and 3D printed.

3D Printing filament PLA : Black (any colour to suit personal preference is applicable)

M3 x 10mm countersunk machine screws: Qty 2

M3 nuts: Qty 2

May prove more cost effective to buy a range of values rather than individual values unless you already have them available. Some components may also have a MOL greater than the quantity specified in the component list.

Tools

3D Printer

Needle files

Sanding paper

Craft knife

Soldering Iron

3D printing Pen

Screwdriver

Drill

Drill bit 1.5mm

Drill bit 3mm

Drill bit 5mm

Long nose pliers

Know your tools and follow the recommended operational procedures and be sure to wear the appropriate PPE.

The 3D printed elements were designed using TinkerCAD Codeblocks, sliced using Cura 4.5.0 and printed on a Labists ET4.

The three piece redesign would be hinged at two locations on the circumference to enable the clamp to open and close for fitting and/or removal.

The existing extension springs, M5 hinge bolt and M4 clamp bolt from the original design will be reused on the redesign.

The body will be more substantial than the original even with the addition of strategically placed cutouts.

TinkerCAD files: drillguardclamp

Designed using CodeBlocks the process is detailed below:

1: Main Body.

This consists of a cylinder with a radius of 41.5mm with a height of 12mm

From this would be subtracted a cylinder of radius 20mm with a height of 12mm.

In addition a torus would be subtracted with radius 30mm and tube radius of 4mm set -6mm in to the cylinder.

Into the cylinder within the area bound by the torus were subtracted 12 x cylinders with radii of 3mm.

The torus and the 12 cylinders help to save material when printed.

Referenced to x:0,y:0,z:0

*It was noticed that increasing the value of sides at 64 for cylinder was effective at smoothing whilst even at 128 the torus was less effectively smoothed.

In preparation for the countersunk screws heads in the wing hinges a paraboloid of radius 3mm and height of 20mm is Scaled x:1.3, y:1.3, z:0.5 and Moved to x:38,y:-17,z:-4 with an identical paraboloid at x:-38,y:-17,z:-4

1a: Clamp

A Box with a split, a bolt hole and two nut recesses on opposing sides.

This allows the clamp bolt to be fitted on either side and if the bolt head is smaller than the nut recess a washer should be fitted,

This consists of a Box with dimensions of w:20, l:18:, h:12 Moved to x:0, y:49, z: 0

Subtracted from this is a Cylinder with a radius of 2.1mm with a height of 30mm, rotated around the yaxis by 90 degrees and Moved to x:0, y:49, z: 0. This is the M4 bolt hole.

From this is also subtracted a Polygon with sides of 6 (hexagon), Scaled to x:1, y:0.4,z: 0.4 and Moved to x:15, y:49, z: 0. This is the recessed hole for the a nut.

From this is also subtracted a Polygon with sides of 6 (hexagon), Scaled to x:1, y:0.4,z: 0.4 and Moved to x:-15, y:49, z: 0. This is the recessed hole for the a nut on the opposite side.

In addition is subtracted from both the Main body and the Clamp a polygon with sides of 3 (triangle), Scaled to x:0.3, y:10,z:1 and Moved to x:0, y:60, z: 0. This is the compression split.

1b: Wings

The winges are created by removing a segment of the Main body ring.

Subtracted is a Polygon with sides of 3 (triangle), Scaled to x:15, y:8,z: 1, Moved to x:0, y:-42, z: 0. and rotated around the xaxis by 180 degrees. This creates the separated hinge wings. (See last part of blockcode in Step 3)

1c: Wing cut outs

This creates clearance at the tips of the wings to accept the rotating portion of the guard front and M3 screws.

Subtracted from the Main body is a cylinder with a radius of 9mm* & a height of 12mm and Moved to x:38, y:-17, z: 6.

Also subtracted a Cylinder with a radius of 1.6mm with a height of 12mm and Moved to x:38, y:-17, z: 0.

This is repeated for the other wing and Moved to x:-38, y:-17, z: 0.

*9mm to create 1mm clearance around the hinge to minimize binding of the hinge due to friction and aid screw hole alignment.

2: Wing Hinges

The wing hinges are created by adding cylinders with centre screw holes.

This is a cylinder with a radius of 8mm with a height of 6mm.

Subtracted from this is a cylinder with a radius of 1.6mm with a height of 6mm.

A countersink on the underside for the screw head is formed by subtracting a paraboloid of radius 3mm and height of 20mm which is Scaled x:1.3, y:1.3, z:0.5 and Moved to x:0,y:0,z:-4 grouped and Moved to x:38,y:-17,z:3 with an identical paraboloid at x:-38,y:-17,z:3.

3: Spring Board

The spring board is part of the front guard with two holes to attach the springs.

This comprises a Box with dimensions of w:42, l:10:, h:3, Moved to x:0, y:-39, z:10.5

Subtracting a cylinder with a radius of 1mm with a height of 20mm and Moved to x:18,y:-40,z:7

This object is repeated and Moved to x:-18,y:-40,z:7

This is then grouped.

4:Guard Front

As per the Main body this consists of a Cylinder with a radius of 41.5mm with a height of 12mm

From this would be subtracted a Cylinder of radius 20mm with a height of 12mm.

From this is also subtracted is a Polygon with sides of 3 (triangle), Scaled to x:15, y:8,z: 1 and Moved to x:0, y:-43, z: 0 and rotated around the xaxis by 180 degrees and grouped.

Referenced to x:0,y:0,z:0

In addition a Torus would be subtracted with radius 30mm and tube radius of 4mm set -6mm in to the cylinder.

Into the cylinder within the area bound by the torus were subtracted 12 x cylinders with radii of 3mm.

The torus and the 12 cylinders are means to reduce material whilst retaining strength.

This creates a section of the Main Body that would create the wings minus the clamp.

The following steps subtract this from a new ring shape to create the front part of the guard.

This consists of a cylinder with a radius of 41.5mm with a height of 12mm

From this would be subtracted a cylinder of radius 20.0625mm with a height of 12mm.

The cutout for the hinges are created by subtracting cylinders with centre screw holes.

This is a cylinder with a radius of 8mm with a height of 6mm.

Subtracted from this is a cylinder with a radius of 1.6mm with a height of 6mm.

Moved to x:-38, y:-17, z: 0.

This object is repeated and Moved to x:38, y:-17, z: 0.

To this are added the cylinder hinge elements complete with screw holes and recesses for the M3 nuts.

This is a cylinder with a radius of 8mm with a height of 6mm.

Subtracted from this is a cylinder with a radius of 1.6mm with a height of 6mm.

From this is also subtracted a polygon with sides of 6 (Hexagon), Scaled to x:0.35, y:0.35,z:0.5 and Moved to x:0, y:0, z:5 and grouped.

Then Moved to x:-38, y:-17, z:9

This object is repeated and Moved to x:38, y:-17, z: 9.

The separate objects comprising the front guard are consolidated into a new single object.

Then Moved to x:0, y:-20, z:0 for clear separation.

5: Front Hinge

This is the angled front part of the guard with a hinge hole and wedge stop at the front.

A Box is created of w:16.5, l:-10, h: 22, Moved to x:0, y:6.8, z:12 and rotated 45 degrees on the xaxis.

Added to this is a cylinder with radius of 5mm and height of 16.5mm, Moved to x:0, y:0, z:19 and rotated 90 degrees on the yaxis.

A Wedge is added Scaled to x:0.825, y:0.5, z:0.5, Rotated on the xaxis by 180 degrees and Moved to x:0, y:-3.3, z:15

A Box of w:20, l:-10, h: 2 is subtracted and Moved to x:0, y:7, z:1 this flatters the point at the edge of the box.

A cylinder is subtracted with radius of 3mm and height of 20mm, Moved to x:0, y:0, z:19 and rotated by 90 degrees on the yaxis to make a bolt hole in the cylinder.

This is grouped and rotated on the yaxis by 180 degrees and Moved to x:0, y:-75, z:-13 to sit at the end of the guard front.

The two separate objects of the front guard and front hinge are consolidated in to a new separate object this is rotated on the xaxis by 180 degrees and Moved to x:0, y:0, z:10.

This orientates the object the correct way up for printing.

Filament: PLA Black

Layer Height: 0.15mm

Wall thickness: 2mm

Infill Density: The wall thickness at 2mm allows a strong print at 10% infill, increased infill will offer greater strength.

Infil Pattern: Lines

Build Adhesion: Skirt

No supports

Size: 122(L) x 92(W) x 22(H) mm

Weight: ~41g

The file is supplied orientated for printing directly.

Remove any aberrations with sanding paper and/or file, paying particular attention to the rotating surfaces of the hinge to enable a close fit and alignment of the screw holes

The clamp is attached to the clear guard by a hinge whose hole may require clearing with a 5mm drill bit.

The clamping screw hole may require clearing with a 3mm drill bit.

The fixing holes for the springs may require clearing with a 1.5mm drill bit.

A soldering iron can also be used to perform repairs (filling gaps or surface smoothing), make sure to set the temperture to the filament melting point or lower to prevent burning the material. However, a 3D printing pen will also perform a similar task.

In either case apply adequate ventilation and/or extraction whilst limiting exposure and using appropriate PPE.

In the fixed front part of the clamp are predesigned depressions to accomodate the M3 nuts.

In order to reduce the likelyhood of these coming loose during use (although they do face upward), is by gluing or applying a little heat with a soldering iron directly to the nut whilst pressing into the depression.

Fit the screw into the hole in the moveable hinge wing directly without widening with a drill to enable a tight fit to reduce loosening due to vibration in use.

Align the moveable hinge wings over the fixed hinge and with thread lock (paint or varnish could be substituted), on the screw thread tighten the screw.

Repeat for the second hinge.

Using the existing clamping nut fit this into the predesigned depression by gluing or applying a little heat with a soldering iron directly to the nut whilst pressing into the depression.

Fit the front part of the clamp to the guard at the hinge point with the existing M5 screw and nut.

Fit the existing springs attached to the guard via the holes either side of the fixed hinge.

Verify that the hinge wings move (they should retain in position once moved), with resistance.

Open the hinge wings to allow the clamp to fit around the drill head.

Close the hinge wings, insert the clamping screw and tighted with a screwdriver

Hope you found this of interest.