Holding the upper stripping blade of a cut-and-strip machine
In the illustrated cutter head, the upper holder clamps a V-notched blade above its lower partner while straightening rollers feed the wire between them. When the head closes, the two blades bypass each other, cut through the insulation to a set depth and pull the slug off. The holder's job is to keep its blade square, on centre and at the right closed height; what the blade itself can do depends on its profile. Lakes Precision's blade catalogue and two stripping-blade patents describe the options and the failure modes.
Covers the upper blade and its holder in automatic wire cut-and-strip machines: blade profile classes and what each allows, shut height and adjacent wire sizes, wire guides, even penetration of the opposing blades, and the conductor damage that uneven or wrong blades cause. Complete strip-and-tin machines are on Automated Wire Stripping and Tinning Machine (360); crimp force monitoring on Force Monitoring System (2957); terminal feeders on 2956; wire straighteners on 4414. Slitter knives and knife holders for converting machines share the name but are outside this page.
CNFX editorial research · Sources checked October 13, 2026 · 3 sources
Four blade profiles and the wire range each covers
Lakes Precision's blade catalogue for Schäfer/Megomat machines describes each blade class by how its edge is ground and what that allows.
Artos's patent on a universal stripping blade sets the same trade-off from the other end: a die-type blade whose closed hole matches the conductor controls cut depth and prevents nicking but serves one wire size; a V blade with a base radius covers only a slight range of sizes; a 90° V with little or no radius covers more sizes but cannot form a full circle round the conductor, leaving insulation uncut.
For the holder this means the blade change is the setting change: a true-radius pair has to be swapped for every wire size, while a universal V can stay in the holder over a range.
Blade class (Lakes Precision)
Edge geometry
Strength
Limitation
Universal V strip blade
Ground to a V opening of exactly 90°, with a very small or no radius
One blade setup for a wide range of wire sizes; adequate for standard-wall insulation
Marginal for thin-wall, cross-linked insulation
TA-V / UN-V tangent-radius V
Edge tangent to an arc approximating the AWG size; closed it forms a diamond profile
Shut height can be adjusted for adjacent wire sizes if insulation and wall allow
Inadequate for thin-wall or hard insulation such as cross-link or fibreglass jackets
TR-V true-radius V
Half circle approximating the AWG size, entry lines meeting it at the quadrant points; closed it forms a true circle
Clean jacket removal, combining bypass shearing with a hole matching the conductor; suits thin-wall cross-link PVC and rubbery insulation
Shut height cannot be changed for adjacent sizes; off-centre wire must be allowed for in sizing
CL-R collinear radius
Half circle with a straight shearing edge; closed to shut height it forms a circle
Precise removal over layered coverings such as fibre over plastic or plastic over shields
Same as true-radius
Blade classes and part sizes are Lakes Precision's for Schäfer/Megomat machines; other machine makers use their own blade families.
02
Shut height, wire guides and the off-centre wire
Shut height is the closed position of the cutter head, the distance the holder brings the upper blade down to. It is the one adjustment that turns a blade class into a cut depth.
Lakes Precision pairs radius blades with wire guides and asks for an allowance for off-centre wire; a blade held off the wire axis would turn a true-radius blade's exact hole into an eccentric one (editorial reading).
Lakes Precision offers its blades with a TC coating option across the classes listed.
Item
What the sources state
Tangent-radius V
Adjusting shut height lets one blade process adjacent wire sizes, where insulation material and wall thickness allow (Lakes Precision)
True-radius and collinear radius
Shut height is fixed by the blade geometry; adjacent sizes need another blade (Lakes Precision)
Wire guides
Used with collinear radius strip blades to guide the conductor into the strip area, keeping it off the cutting edges and preventing premature blade wear (Lakes Precision)
Off-centre wire
Has to be considered when choosing a radius blade size (Lakes Precision)
Shut-height values belong to the machine's own settings table; this page does not give them.
03
Nicks, uncut insulation and chipped tips: what goes wrong between the blades
The Whitaker (AMP) patent on optimized stripping blades lists the failure modes of an opposing V-blade pair that a holder and blade set have to avoid.
Even penetration is a holder property as much as a blade property: upper and lower blades have to be square to each other and centred on the wire so both reach the same depth. A chipped tip, in Whitaker's description, gives an uneven cutting profile, which changes the depth on that blade's side.
Failure
Cause described
Conductor damage
Opposing blades do not penetrate to the same depth; if one is close to the conductor and the other shallow, further closure risks damaging the conductor (Whitaker)
Incomplete strip
Insulation compression causes slippage between the blades (Whitaker); insulation left uncut has to be torn from the parent insulation (Artos)
Chipped blade tip
The sharp, fragile tip is loaded in bending as the blade pair pulls the slug off; chipping gives an uneven cutting profile and shortens blade life (Whitaker)
Blade damage from a terminal
An electrical terminal placed between the opposing stripping and cutting blades during operation (Whitaker)
Why nicks matter
A nick reduces the conductor's current-carrying capacity and creates stress concentrations that lower its tensile strength (Artos)
Neither patent gives a nick or strand-damage acceptance limit; use the harness standard or customer specification that applies.
04
What to give for upper blades and holders
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Give the machine make and model, wire cross-sections and outer diameters, insulation material and wall thickness, layered coverings or shields, required strip lengths and partial-pull needs, and the conductor damage limits the harness must meet. Ask for the blade class and part number per wire size, whether shut height can cover adjacent sizes, matching wire guides, coating options, holder alignment features, and blade life expectations.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
Which stripping blade covers the widest range of wire sizes?
Lakes Precision describes the universal V blade with a 90° opening as able to process a wide range of sizes with one setup, adequate for standard-wall insulation but marginal for thin-wall cross-linked insulation. [1]
When is a true-radius blade the better choice?
For clean removal of thin-wall cross-link PVC and rubbery insulation, where Lakes Precision's TR-V blade closes to a true circle; its shut height cannot be adjusted for adjacent wire sizes. [1]
Why does uneven blade penetration nick the conductor?
The Whitaker patent explains that if one blade is close to the conductor while the other is shallow, closing further to finish the cut risks damaging the conductor. [2]
Why are nicks a problem?
Artos's patent states that a nick decreases the conductor's current-carrying capacity and produces stress concentrations that decrease its tensile strength. [3]
Sources and what still needs a direct check
Sources checked 2026-10-13. A blade maker's catalogue for Schäfer/Megomat cut-and-strip machines and two US patents on stripping blades, from Whitaker (AMP) and Artos.
