Specify the operation before the head
UNISIG distinguishes tools that drill from solid, counterbore an existing hole, and trepan while leaving a central core. Its BTA range includes brazed and indexable heads. These categories describe different deliveries; they are not interchangeable quotations. Original tooling descriptions.
For a purchase comparison, write the incoming condition and outgoing requirement side by side. ‘BTA tool’ alone does not say whether the supplier is removing solid stock, enlarging a pre-bore or producing a finished internal profile.
Build a complete tool identity
| Record | Why it belongs in the comparison |
|---|---|
| Operation and pre-bore | Establishes which material is removed |
| Head designation and cutting diameter | Identifies the proposed cutting assembly |
| Insert, pad and cartridge references | Defines the actual replacement parts |
| Tube and head connection | Makes mechanical compatibility reviewable |
| Entry and support arrangement | Connects the tool quotation to the machine setup |
| Setting and inspection procedure | Defines how a replacement assembly is returned to service |
This is an editorial documentation checklist. Approval belongs to the machine and tool instructions for the named assembly.
Replacement is a setting task
UNISIG’s German head comparison describes directly mounted inserts and cartridge-mounted arrangements, including adjustment systems for the latter. BTA head constructions.
Ask the supplier to demonstrate a complete replacement cycle: identify the spent part, inspect the seating arrangement, apply the supplied setting procedure, measure the resulting assembly and retain its inspection record. Record the time required for this whole cycle rather than quoting only the screw-change time.
Compare cost per accepted delivery
Our suggested trial sheet separates head purchase, consumables, setting time, machine time, inspection and rejected work. Report the sample size and the bore acceptance criteria next to the result. A cheaper insert is not sufficient evidence for a cheaper accepted hole. See the brazed and indexable comparison and bore-quality worksheet.
Separate the cutting task from the machine family
UNISIG’s tooling descriptions distinguish drilling from solid, counterboring an existing hole, pull boring and trepanning that leaves a core. These operations should remain separate in a comparison even when the tools are offered for the same machine family.
An editorial route example makes the distinction concrete: a quotation for a finished bore starts from either a solid blank or an existing bore. In the first case, ask which operation creates the opening. In the second, identify the starting size and geometry before choosing the enlargement or finishing task. A name copied from the equipment list leaves that starting condition unresolved.
Tool construction is another independent choice. A brazed cutting head and a body accepting replaceable inserts have different service arrangements. That does not make either one an automatically cheaper route for a specified batch. Preserve consumables, setup time, inspection and actual accepted output in the comparison.
Use the construction comparison for the cutting assembly and the tube specification for its connection. A compatible cutting head alone does not document the whole tool train.
Revision note
October 8, 2026: revised the technical explanation and connected reading after source review. Original publication date and URL retained.
