Piercing Saw Blade Supplies
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Jeweler's 'piercing saw'

A piercing saw is a small, fretsaw styled, frame saw that has fine blades intended for cutting metal, traditionally used by jewelers, but has uses in model making and any metalworking that requires fine detail. Piercing saws are capable of cutting other materials including wood and plastic, although they are mainly used on metal. The piercing saw gets it's name from the process of making 'blind' cuts or 'piercings' whereby a small hole is first drilled through the work. One end of the saw blade is fitted into the saw frame and the other is threaded through the hole. The open end of the blade is then clamped into the remaining end of the saw frame. When sawing is completed, the saw blade is unclamped from one end of the frame and withdrawn form the work.

Piercing saws have a frame with pinch clamps that will grip the blades, handles are usually turned wooden ones like the one illustrated.

Saw frames are available with throat depths That vary from 50 mm to 200 mm, But if greater throat is required then a fretsaw frame can be pressed into service which extends the range to 450 mm.

The saw illustrated is a photograph of my own, which has a sliding adjustment to cope with differing blade lengths, this also helps in that broken pieces of blade can be used up. The sliding action of this feature is also used to tension the blade rather than the more normal method (described below) that is applied to fixed frames.

The saw blade is fitted into the thumbscrew clamps with the teeth facing towards the handle. The blades are fragile and are caused to cut on the pull stroke so that the blade is held straight by the extra tension due to teeth resistance rather than buckling as it would tend to do on a push stroke.

The magnified portion of the blade shows a brown colouration due to copper plating which inhibits rust and also acts as a minor lubricant when cutting hard steel.

Main lubrication is by pulling the blade from end to end across a block of beeswax which lubricates the cutting and renders the cutting action quieter and 'sweeter to the feel'. Household toilet soap can also be used in this fashion and sometimes leads to less clogging when sawing copper or aluminium. I have also used motor oil on some occasions (but this is messy). Petroleum jelly (vaseline) will sweeten the cutting of some zinc based die casting alloys.
Adjustable framed piercing saw with 70 mm throat

Piercing Saw Blades... These come in a wide variety of types, thicknesses and tooth frequency. Generally they are made from hardened and tempered steel, Some have teeth from end to end, others have blank end portions that are intended as clamping areas. Rounded profile of the back, non cutting, edge aids the sawing of curved lines and for really tight curves there are spiral formed blades available. In many of my beekeeping applications I use fretsaw blades as their tooth form and number of teeth per inch are more appropriate to the wood and plywood components that are being worked on.

packet of fretsaw blades
This packet is fretsaw blades, but piercing saw blades are similarly packed.

spiral form of piercing saw blade
This spiral form is made by twisting a straight cut blade at high temperature.

Blades are available that are suitable for sawing silver, brass, copper, and steel, mostly these are manufactured in Germany and Switzerland. Sizes range from '6' which is the coarsest down to 8/0 which is the finest.

There is a type of flat Saw Blade similar to a 'junior hacksaw' blade, that can be used for straight cuts on rods, bar stock and tubing.

Choice of Saw blade will depend on the material being sawn, it's thickness and nature of the job. For delicate work, and when cutting very thin material you should use a finer blade, but for general purpose cutting, choose a heavier blade as you will break less saw blades.

Loading the piercing saw... Depending on your stature, you will need a small countersunk recess in the leg of your workbench or perhaps on the edge of your bench. Hold the saw frame with it's backbone downwards and with the handle pointing into your stomach, place the nib end of the frame into the recess so that it will not slip. Lean your body so that your stomach holds the handle. Fit one end of the saw blade into the frame clamp, using the thumbscrew. Lean firmly against the handle of the saw frame causing the frame to flex and the other end of the saw blade to enter into the clamp and tighten. When you release the flexing pressure on the frame, the blade will be gripped firmly and be under tension. Test the tension by plucking the blade which should give a high pitched pinging sound. The process is a little different if the frame has an adjustable length... In this case the tension can be applied before the backbone clamping screw is finally tightened, however be warned that the sliding action must not be at all sloppy, otherwise there is a risk of bending stresses at the top end blade clamp, such stresses shorten blade life.

Using the piercing saw... is a relatively simple process that requires considerable practice to master. Breaking of such fine blades is inevitable and is the normal cause of failure, however such breakages will become less frequent with practice and good technique.

Sawing technique... Start by placing the work piece roughly horizontal on a bench peg (see drawings below).
A 'bench peg' is a chamfered wooden block that can be mounted either above or below the edge of a work bench. It is used as a rest for drilling and grinding operations, or when filing and sawing.

When filing and sawing it can be useful to gain a little more control by filing or sawing both the work and the edge of the peg at the same time.

It can sometimes be helpful to have a 'keyhole' shaped slot in the front edge of the bench peg so that the work is well supported and the blade itself is in 'free space'.
general arrangement of a bench peg
The illustration shows the saw reciprocating in an exact vertical plane, however it sometimes can be more prudent to use the saw perpendicular to the work. Thick solid sections are easier to saw if the blade is perpendicular as the amount of material presented to the blade is a minimum, but very thin sections can be more easily sawn at an angle as more teeth are then in contact with the work, which reduces juddering or 'chatter'.

Using the full length of the blade on every stroke, cannot be over stressed, it is the single most important factor in blade life, although skill and rhythm that is developed by practice also go a long way towards saving blades.
action of sawing using a bench peg

I was lucky in having a very skilled tutor who taught me to use the piercing saw and many other delicate tools when I was a child of six or seven years. I learned a great deal from this man, his name was Hugh Burn (Huie) and he was a dental mechanic (orthodontist) of considerable ability.

Written... 21 to 31 January 2004, Upgraded... 17 August 2004,
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