Big Mach Kit – Instructions download


  • Introduction
  • Items Enclosed
  • Materials Required
  • Anatomy of the BIG MACH
  • Constructing the BIG MACH
  • Fitting the Ball Valves
  • Fitting the Top Gasket
  • Fitting the Centre Sealing Gasket and Bottom Support Gasket Strips
  • Fitting the Control Tap to the Base Board
  • Assembling the Bed
  • Suggested Portable Workbench Cramping Bar Dimensions
  • Assembling and Setup
  • Operation
  • Trouble Shooting
  • Important factors
  • How to Template and Shape Copy with the BIG MACH
  • Environmental Protection
  • Guarantee
  • Safety Points


The BIG MACH KIT provides all the essential components for the construction of an industrial sized vacuum hold down system. The plans enclosed detail a sealed cavity unit of 1120 x 520 x 48mm. However, using multiple BIG MACH KITS, larger beds can be made.

The BIG MACH can be powered by your workshop or domestic vacuum cleaner. The BIG MACH enables you to  hold workpieces for hand held machining processes, leaving the top surface clamp free.  The BIG MACH is dependent on one single item, a cylinder vacuum cleaner.

Please read this manual carefully before starting this project. The BIG MACH can be used to hold components whilst:

  • Routing
  • Sanding
  • Templating
  • Hand planing
  • Biscuiting / Joining
  • Circular sawing

Your vacuum cleaner should be:

  • Minimum 1000watts
  • Fitted with detachable nozzle and hose. (size 27mm – 34mm internal diameter)
  • Fitted with a clean dust bag

Please Note:

The BIG MACH is not suitable for cyclone  cleaners such as a Dyson.

The BIG MACH will not hold rough sawn timber or material which is seriously cupped or twisted.

Holding Specifications

Min. component size 95 x 95 mm

Max. component size 2240 x 1220 mm



  1. A.  4.0 meters of Bottom Gasket
  2. B.  8.0 meters of Top Gasket
  3. C.  Tapered Adaptor
  4. D.  1x Control Tap and Hex Nut
  5. E.  21x Pressure activated Ball Valves
  6. F.  1x Control Tap Plate and 4 x Screws
  7. G.  Control Tap Plate gasket
  8.      1x Instruction and Construction Manual
  9.      1x Cutting and Fitting Guide
  10.      1x Guarantee Card


MDF or marine multiply board: 
Top Board size: 1120 x 520 x 25mm (recommended) 
Base Board size: 1120 x 520 x 18mm (recommended)

The recommended board thickness should be used because thinner sections of board will distort under pressure. Both boards must be totally flat. To test whether the Boards are flat, check corner to corner with a guaranteed straight edge. This is an essential requirement as any cup or twist in the board will  prevent the BIG MACH from working.



Top view of Top Board (see Fig 2)
BMK Ins Man Fig 2

  1. A.  Small Cell – Small area within Top Gasket with Ball Valve
  2. B.  Top Gasket – Provides the seal between
  3. C.  Ball Valve Steel ball with spring that activates the vacuum supply when a workpiece is pushed onto it
  4. D.  Large Cell – Large area within Top Gasket with Ball Valve

Underside view  of Top Board (see Fig 3)

BMK Ins Man Fig 3

  1. A.  Centre sealing Gasket – Seals the internal assembled, this is the evacuation chamber
  2. B.  Internal Support Gasket – Provides support when the air is drawn from the evacuation chamber
  3. C.  Ball Valve holes – These holes link the Ball Valves on the Top Board to the evacuation chamber

Underside view  of Base Board (see Fig 4)

BMK Ins Man Fig 4

  1. A.  Screws – Fixes the Top and Base Boards together   (not  supplied)
  2. B.  Control Tap Plate – The mounting plate for the Control Tap
  3. C.  Cramping Bar – Allows the BIG MACH to be held in a portable workbench


From the Cutting and Fitting Guide mark and cut out the Top and Base Boards. Mark out the Ball Valve positions on the top surface of the Top Board and the Tap Plate position on the underside of the Base Board using the Tap Plate as a template.

CUTTING THE GASKET(see Cutting and Fitting Guide)

Cutting List : Top Gasket








40 1/8″ – (1020mm)

3/4″ – 20mm

1/8″ – 3mm



18 7/8″ – (480mm)

3/4″ – 20mm

1/8″ – 3mm



8 9/16″ – (980mm)

3/4″ – 20mm

1/8″ – 3mm



27 5/16″ – (710mm)

3/4″ – 20mm

1/8″ – 3mm



7 7/8″ – (200mm)

3/4″ – 20mm

1/8″ – 3mm



8 11/16″ – (220mm)

3/4″ – 20mm

1/8″ – 3mm



3 1/2″ – (90mm)

3/4″ – 20mm

1/8″ – 3mm



19/16″ – (40mm)

3/4″ – 20mm

1/8″ – 3mm

Cutting List : Bottom Gasket








40 1/8″ – (1020mm)

1″ – 25mm

1/4″ – 6mm



18 7/8″ – (480mm)

1″ – 25mm

1/4″ – 6mm



3 1/8″ – (80mm)

1″ – 25mm

1/4″ – 6mm



Drill the marked positions using a 1/2″ drill piece. Drive the 21 Ball Valves into the top surface of the Top Board.

Use a hammer and a block of wood, this will protect the finish of the ball valve . (see Fig 5). Ensure that the Ball Valves sits level on the surface of the Top Board (see Fig 6).

BMK Ins Man Fig 5 - 6

FITTING THE TOP GASKET (See Cutting And Fitting Guide)

Lay out the Top Gasket strips as per the Cutting and Fitting Guide to check that all the components fit.
Check that the surface is clean and clear of dust.

Important: Ensure that you only remove the backing paper of the strip that you are about to lay to avoid dust and debris.

Do not press the strips down firmly until they are all laid and you are entirely satisfied with their location.

Do not attempt to stretch the gasket strips into position or try to fill gaps as over time the gasket will return to its original length and the gaps will reappear.

Starting at the bottom right hand side of the Top View diagram (Cutting and Fitting Guide), start to lay the strips of gasket. (see Fig 7) 

Check that all the strips are carefully butted up together, any gaps will reduce the efficiency of the Big Mach when in operation.
If you have to re-lift any of the gasket strips to reposition them, do so slowly as if rushed the material can rip. 

When satisfied that the gasket matrix is complete with no gaps,turn the Top Board over onto a flat clean surface, (any surface debris will distort the gasket). This will apply an even pressure and help the Top Gasket set in position. It will also allow access to the underside of the Top Board for the next stage.

 BMK Ins Man Fig 7


Once again care needs to be taken with the Bottom Gasket strips, see above under the section  (Important:).

Starting at the bottom right hand side of the Underside View of Top Board (Cutting and Fitting Guide) lay bottom strip Q first followed by right hand strip R – left hand strip R and last top strip Q.

Firmly press the strips down once in position.

Fit the Internal Support Gasket strips, without them the Boards may distort when under vacuum.



Mark and cut out the Control Tap Plate Gasket and two holes. Tap hole 1″ – 25mm, Bleed hole 1/10″ – 3mm using the Control Tap Plate as a template.

Put the Control Tap Plate Gasket to one side and position the Control Tap Plate a minimum of 20mm from the edge of the Base Board as per the Bottom view of Base Board (Cutting and  Fitting Guide).

Drill 1x 1″ – 25mm Tap hole and 1x 1/10″ – 3mm bleed hole through the Base Board using the Control Tap Plate as a template.

Push the threaded section of the Control tap through the Control Tap Plate.

Screw the brass lock nut on, pinching it up tightly with the tap, square to the narrow section of the Control Tap Plate (see Fig 8).

BMK Ins Man Fig 8

Plate Gasket and stick it to the underside of the Control Tap Plate (non chamfered edge side).

Fit the Control Tap and Control Tap Plate to the underside of the Base Board ensuring that the Control Tap Plate Gasket lies flat between the two, then screw the Control Tap Plate

into position using the 4 x domed headed Screws. Avoid over compressing the Control Tap Plate Gasket.



Locate the screw positions central to the width of the Centre Sealing Gasket around the peripheral edge of the underside of the Base Board.

Pilot drill and countersink the screw holes through the underside of the Base Board and into the gasket before putting the Top and Base Board together.

Once all the holes have been piloted and countersunk, gently position the Base Board onto the Top Board taking care to align the two boards correctly.

When screwing the Boards together use No. 6 screws at approximately 160mm spacing. Do not over tighten the screws as this will crush the Centre Sealing Gasket. Both sections of board should be in direct contact with the Centre Sealing Gasket. 



To mount the BIG·MACH in a portable workbench it is necessary to make a cramping bar, 3 x 2 pine is sufficient . (see Fig 9 for suggested Cramping Bar dimensions)

BMK Ins Man Fig 9



Fit the Tapered Adaptor by screwing the Adaptor thread into the socket in the Vacuum  Control Tap. Ensure the pipe is tight. Place your BIG MACH on your work surface with the Ball Valves facing up and with the Vacuum Control Tap overhanging one end of the surface (see Fig 11).

BMK Ins Man Fig 10
The BIG MACH can be mounted for either left of right handed users. Check the Vacuum Control Tap is in the OFF Position – at a right angle to the Tapered Adaptor (see Fig 10)

Gently push the open hose end of the vacuum cleaner onto the Tapered Adaptor. If it does not fit, use one of the extension pipes that comes with the cleaner which should have an approx. sized bore of (27-34mm) Ensure that the Tapered Adaptor is kept clean and clear of dust and debris. Failure to do so can lead to overheating and damage to your vacuum cleaner.

BMK Ins Man Fig 11



  1. 1. Switch on the vacuum cleaner. Check the position of the BIG MACH and turn the Vacuum Control Tap ON – in line with the Tapered Adaptor (see Fig 9 – page 7) The BIG MACH is now ready to hold your work .
  2. 2. Your workpiece must :
    1. A. Be relatively flat and impermeable
    2. B. Cover a minimum of one cell completely (the holding capacity of the BIG MACH is directly determined by the capacity or strength of your vacuum cleaner)
    3. C. Cover the maximum number of cells completely.
  3. 3. Once in position, press down on your work-piece to secure it. This action opens the Ball Valves and creates a vacuum just under your work-piece.
  4. 4. Always check that your work is held firmly before you start work and that the holding force is appropriate for the operation you wish to undertake. The BIG MACH is capable of supporting the weight of an overhang (up to 1m depending on the weight and porosity of the board) However the vacuum seal and the grip may be broken by either lifting or pressing down on an unsupported overhang, so ensure that the BIG MACH is directly under the area of the work-piece you are currently working on.
  5. 5. To remove your workpiece, turn the Vacuum Control Tap to OFF Position. This will cut the supply of vacuum and the board will be released. Particular care should be taken when releasing the vacuum if you are holding a piece of work with a large overhang.
  6. 6. Do not drag or wrench your workpiece from the BIG MACH as this can damage the Rubber Gasket.
  7. 7. Keep your BIG MACH free from dust and debris to optimise its performance.
  8. 8. Run your vacuum cleaner only when using the BIG MACH . We recommend a maximum continuous running time of 30 minutes with a 10 minute break to ensure the optimum life of your vacuum cleaner motor.


The BIG MACH will not hold down work:-

Check the work covers as many cells completely as possible.

Check that your work is flat by resting it on a known flat surface, if it rocks from corner to corner, it may not form a seal with the BIG MACH rubber gasket.

How do I know its working ?

Always check the workpiece is secure before starting to machine it. Push against it to test it is held firm. Do not lift the work as this will break the vacuum seal.

Working on workpieces with an overhang:-

Always support the workpiece when it overhangs the BIG MACH. This will prevent the weight of the machine tipping the work-piece and breaking the vacuum seal.

 BMK Ins Man Fig 12
BMK Ins Man Fig 12b


The BIG MACH generates a high force perfect for holding work when routing,belt sanding etc. However, components cannot be held effectively on edge and workpiece overhangs must be supported.

The strength of the holding force corresponds directly to and increases with, the number and size of cell(s) activated and sealed under the workpiece.

4 x 4″ – 100 x 100mm or an equivalent size is the smallest component that is recommended to be safely held for light routing and sanding purposes.

Power Sources

The BIG MACH can be driven by a vacuum pump or a compressed air venturi.

Remove the tapered adaptor and using 1/4″ BSP fittings to attach your chosen vacuum source to the BIG MACH.

Both vacuum sources produce high pressures and low volumes of vacuum so it is essential that the 2mm bleed hole in the Vacuum Control Tap Plate be sealed off and that the workpiece being held does not activate Ball Valves without sealing the cell off completely.

Permanent Bench Top

The BIG MACH can be permanently mounted as a bench top on a standard workbench or on top of a storage cabinet for power tools. Alternatively, with the addition of a Cramping Bar (see page ) on the underside and be held effectively in a portable workbench.

Securing the BIG MACH

Ensure any fixing screws for mounting brackets,glass plates, bolts etc. do not penetrate the central vacuum cavity.

It is advisable to make a drop on cover to protect the BIG MACH when not in use. Do not leave tools or other heavy objects on the top surface of the BIG MACH as the gasket material can be permanently damaged.



To repeat a shape or a component accurately is traditionally a very time consuming business – usually involving pinning the workpiece to the template or double side taping the two together, then holding the two components down to your bench before routing. this method also means unnecessary time spent cleaning up or even filling the holes in the component.

A NEW process has been developed using the BIG MACH,which greatly simplifies this process – Saving you time and hassle.

Using the remaining Top gasket material,cut 3/4″ – (20mm) width section into 2 x 3/8″ –  (10mm) strips.

Using the remaining Top gasket material, cut 3/4″ – (20mm) width section into 2 x 3/8″ –  (10mm) strips.

Mark and cut out the component or shape you wish to copy, from a nonporous material i.e. melamine chipboard, bloc board, veneered/sealed  M.D.F or plywood. The ideal thickness  is 3/4″ – (18mm).

Ensure that the edge of the template is smooth for the cutter bearing to run on, as any irregularity will be copied into the workpiece . Time spent on preparation of your template is a wise investment.

Apply a single strip of gasket material round the edge of the template 3-Smm from the edge,cut the gasket ends at a slant as this helps the two ends meet and seal.

Drill an 8mm air extraction hole through the template. (see Fig 13)

BMK Ins Man Fig 1

Position the template on the workpiece, draw round the template and rough cut your workpiece to within 3 – 5mm of your template line. A bandsaw or jigsaw is ideal for this purpose.

Position the template on the BIG MACH completely covering as many cells as possible and ensuring that the air extraction  hole is directly over an activated cell. This allows the BIG MACH (when switched on) to remove the air from between the template and the workpiece,  locking them together  (this grip may be stronger than the grip between the template and the BIG MACH, this is entirely  normal). Check that the workpiece allows and even overhang around the template. Turn the vacuum cleaner on and the Control Tap on and press the two down together  holding them for approx. 2 seconds to allow the vacuum seal to form between the components.

Prepare your router – fitting a bottom bearing trimmer cutter and set the depth stop to allow the bearing to run in the centre of the template edge.

before starting your cutting pass re-check that the template and workpiece are securely locked down.

Slowly rout around the workpiece, a single cutting pass should be sufficient ,only if the workpiece overhang exceeds 3mm might a second cutting pass be necessary.

Your copy should now be finished.



Recycle raw materials instead of disposing as waste.

Packaging should be sorted for environmental-friendly recycling. The product and its accessories at the end of its life should be sorted for environmental-friendly recycling.



All MPOWER products are guaranteed against any defects in either workmanship or material, except products that have been damaged due to improper use or maintenance.

Our policy of continuous improvement means that specifications may change without notice. MPOWER Tools Limited cannot be held liable for any material rendered unusable, or for any form of consequential loss.



  1. Always switch off the power and unplug power tools when making adjustments to them.
  2. Always wear protective goggles when machining.
  3. Wear sound protective ear muffs when machining.
  4. Always wear a dust mask or respirator. Use dust extraction whenever possible.
  5. Do not wear loose clothing. Make sure baggy sleeves are rolled up, long hair tied back  and ties are removed.
  6. Keep hands well away from the moving parts of machinery.
  7. Avoid accidental starting of machinery by ensuring the power switch is in the off position before plugging into an electricity supply.
  8. Periodically check all nuts and bolts to ensure they are tight and secure.
  9. Always support overhangs when working on them.
  10. Always test your workpiece is being held to a sufficient level before proceeding to work on it.
  11. Make sure your work area is free from hazardous obstacles and trailing cables.
  12. Always follow instruction manual before using a new product.

If after reading this manual you have any problems or queries please contact our Technical Support Department.


Manufactured by MPOWER Tools Ltd™

UK Design Registration 300363, US & EU Design Patents Pending, US, EU & UK Patents Pending

Manor Farm, Newton Tony, Salisbury, Wiltshire, SP4 0HA 
Tel: +44 (0) 1980 629 526 – Email: [email protected] – Website: 

© MPOWER Tools Ltd™ 2012