Hand Tool Comparisons · Reviewed October 29, 2026
General Tools 78 vs 79: Full-Size or Mini Center Punch?
Both make a center mark with a spring-driven stroke instead of a hammer. The meaningful choice is a larger body versus a shorter, narrower one, with different point sizes and replacement parts. Neither is an automatic hole-location system.
Best for
People choosing a handheld automatic center punch for layout work and deciding which body size fits their hand, access space and tool storage.
Probably not for
Anyone needing a specified impact-energy rating, a pin-removal tool, a hinge-centering guide or a promise that every drill bit will start without wandering.
Specifications at a glance
| Manufacturer detail | General Tools 78 | General Tools 79 Mini |
|---|---|---|
| Exact model | 78 Heavy-duty Automatic Center Punch | 79 Mini Heavy-duty Automatic Center Punch |
| Overall length | 5-5/8 inches | 4-7/8 inches |
| Body diameter | 5/8 inch | 1/2 inch |
| Published point diameter | 0.083 inch (2.1 mm) | 0.055 inch (1.4 mm) |
| Body and grip | Steel; knurled grip; black oxide finish | Steel; knurled grip; black oxide finish |
| Adjustment | Adjustable spring tension | Adjustable spring tension |
| Named replacement point | 78P | 79P or 79P/2 |
| Purchase compared | One complete punch | One complete punch |
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General Tools 78 Heavy-duty Automatic Center Punch
The larger of these two steel-bodied tools, with an adjustable spring mechanism and a replaceable hardened-steel point. It is a complete punch, not the separate 78P service part.
Pros
- Wider body is an option for shoppers who prefer a larger grip
- Manufacturer identifies the matching replacement point by model
- Adjustable mechanism avoids committing to one fixed stroke setting
Cons
- Longer and wider form needs more clearance and storage room
- Its point specification does not define the finished indentation size
- No comparable impact-energy specification establishes a power advantage here
Who it’s for: Choose it if the larger diameter suits your grip and there is room above the intended marking position. Skip it when minimizing tool size is the main reason for buying.
Check General Tools 78 Heavy-duty Automatic Center Punch on Amazon Paid linkGeneral Tools 79 Mini Heavy-duty Automatic Center Punch
A shorter, narrower member of the same tool category, retaining spring adjustment and a replaceable hardened-steel point. Mini describes the form factor; it is not a certification of finer layout accuracy.
Pros
- Smaller body offers an alternative for limited tool-storage space
- Keeps an adjustable spring mechanism in the mini format
- Manufacturer lists replacement-point identifiers for this exact model
Cons
- Narrower grip may not be the hand position you prefer
- Smaller point diameter does not guarantee a more accurate mark
- Replacement points must be matched to 79 rather than assumed interchangeable with 78
Who it’s for: Choose it if the compact body is a concrete advantage in your kit or workspace. Skip it if you are shopping for a larger grip or assuming mini means suitable for every delicate surface.
Check General Tools 79 Mini Heavy-duty Automatic Center Punch on Amazon Paid linkChoose the tool for the marking step
An automatic center punch is useful when you want to turn a laid-out location into a small indentation before drilling. It does not measure the hole spacing or decide where the center belongs. That distinction is worth making before comparing models: replacing an ordinary pencil mark with a punch mark will not correct an incorrectly measured distance, a misunderstood drawing or a reference edge chosen on the wrong side of the workpiece.
Both models here use a push-operated spring mechanism. The point is positioned on the intended mark and downward pressure triggers the stroke; no separate hammer is needed. This is the same purchase category on both sides of the table, not a comparison between an automatic punch and a hammer-struck solid punch. If you actually need to drive out a pin or locate the middle of a hinge hole, choose a tool designed for that task.
Start with body size, then check access
The 78 is the candidate to examine when you prefer a larger-diameter tool. The 79 is the candidate when a compact form is useful. Think about how you normally hold a marking tool, including any gloves required for the job. If you can inspect the models in person, check whether you can position the point while maintaining a usable grip. The diameter alone does not tell us which one will feel comfortable in your hand.
For a location near a raised edge, look at the whole movement rather than just the length of the punch. You need space to place it and press without an obstruction pushing your hand out of position. A shorter tool is a reason to check the 79, not evidence that it will fit every recess. Sketch the working space or measure the obstruction before ordering; the published overall dimensions are not an access-clearance drawing.
Point diameter is not a drilling specification
The point diameters in the table are manufacturer specifications for the tools. They are not stated finished-hole sizes, and this guide does not equate them with the diameter or depth of the mark left in your particular material. Avoid choosing solely by matching that number to a drill bit. The intended hole, workpiece and drilling process still need to be considered separately from the size of the punch point.
Likewise, a smaller listed point does not establish that the 79 places a mark more accurately. Layout visibility, placing the tool on the intended spot and keeping the work stationary remain separate tasks. For repeatable hole patterns, make a reference plan before marking the first piece. Our combination-square comparison is relevant if setting out lines and offsets is the part of the workflow you need to improve; buying a punch is not a substitute for that layout tool.
Adjustment is useful without inventing a power ranking
General Tools documents adjustable spring tension on both models. That shared feature matters if you want to change the stroke setting, but it does not separate them into a precise light-duty and heavy-duty performance scale. Both manufacturer names contain heavy-duty. There is no matched impact-energy test in this comparison, so the larger 78 is not declared more powerful and the smaller 79 is not assigned a measured reduction in marking force.
For a new project, establish the appropriate setting using the tool instructions and a suitable offcut before committing to the finished part. Inspect the result rather than assuming a setting transfers unchanged between different materials or thicknesses. If your work requires a documented impact range or a specifically approved material hardness, ask for that information before buying. Neither of the specifications collected here answers those requirements, and a product name is not a technical rating.
Plan for service parts without buying the wrong item
Both product pages identify replacement points, but the model references differ. Keep the complete-tool number with your workshop records so that a later parts order starts with the correct identity. Check the full part designation and package quantity before paying. A search result containing the tool name may be for a replacement point rather than the complete spring-loaded punch, and a low-looking listing total is not evidence that the two packages are comparable.
Do not assume a replacement point fits merely because it is made by the same company or looks similar in a photograph. Nor does having a named service part guarantee that a seller currently has it. The useful buying question is whether you can identify the appropriate part and obtain manufacturer guidance when needed. This article does not promise a service life, a repair cost or a schedule for replacing the point.
Support the work and protect the layout
Before making the mark, check that the workpiece is stable, the intended location is visible and your hands are clear of the point. Use appropriate eye protection and follow the tool instructions. The lack of a separate hammer does not make the point harmless. A center mark is a physical change to the surface, so pause to verify orientation and measurements before pressing, especially where the marked face will remain visible.
Workholding deserves its own decision. Our trigger-clamp comparison can help with choosing a clamp format, but it does not establish that either clamp is suitable for every metalworking setup. Select support and clamping appropriate to the actual part and operation. A component that moves while you position the punch is a workholding problem; changing from the 78 to the 79 does not automatically solve it.
The short buying decision
Choose the 78 when its larger body is the fit you want; choose the 79 when the compact body has a practical purpose. If neither size changes your grip, access or storage decision, this documentation does not establish a universal winner. Compare the exact complete-tool package and current seller terms without treating a brand adjective, customer star average or hypothetical speed advantage as evidence of better results.
Manufacturer documentation and Amazon identities were checked on October 29, 2026. General Tools links directly to these ASINs. Amazon identifies models 78 and 79, each as one item; the 79 title also uses 318-79. The 78 listing contains unrelated manufacturer and item-type fields, so its technical details are taken from General Tools instead. Confirm the model and package before buying. This documentation-led comparison does not claim hands-on testing or use customer reviews as evidence.
Official sources and further reading
Sources reviewed on October 29, 2026. Prices, availability and terms can change; recheck before buying.
- General Tools: current model 78, dimensions, point size, construction, adjustment and 78P replacement point
- General Tools: current model 79, dimensions, point size, construction, adjustment and replacement-point references
- Starrett: center-punch purpose, distinction from other punches, automatic operation and eye-protection guidance
- Amazon: General Tools 78 model and single-item identity, reached from the manufacturer buying link Paid link
- Amazon: General Tools 79 model and single-item identity, reached from the manufacturer buying link Paid link
Commission disclaimer
This article contains affiliate links. If you buy or sign up through one of them, I may earn a commission at no extra cost to you. That commission does not change the price you pay or the criteria used in this guide. Product details, prices, availability, and terms can change, so confirm the current information on the linked page before buying.