The McCulloch 1-70 is a large 87cc American-made chainsaw produced from June 1959 until July 1960. With direct drive, manual chain oiling, rigid handles and a powerhead weighing 19.5 pounds, it is a classic example of McCulloch’s heavy-duty saws from the late 1950s.
The saw pictured here retains the correct yellow-and-black color scheme, including its distinctive “Number One in World Sales” top decal. It is also fitted with a long guide bar and an unusually aggressive set of bumper spikes!
McCulloch 1-70 specifications
| Specification | McCulloch 1-70 |
|---|---|
| Manufacturer | McCulloch, Los Angeles, California, USA |
| Model | Mac 1-70 |
| Production period | June 1959 to July 1960 |
| Operator configuration | One-man chainsaw |
| Engine type | Single-cylinder, air-cooled, two-stroke |
| Engine displacement | 5.3 cu. in. / 87cc |
| Cylinder bore | 2.125 in. / 54mm |
| Piston stroke | 1.500 in. / 38mm |
| Piston rings | Two |
| Cylinder construction | Aluminum cylinder with cast-iron sleeve |
| Induction system | Reed valves with third-port induction |
| Advertised horsepower | Not published by McCulloch |
| Powerhead weight | 19.5 lb / 8.8kg |
| Construction | Die-cast magnesium and aluminum alloy |
| Handle system | Rigid |
| Anti-vibration system | None |
| Chain brake | None |
| Clutch | Centrifugal |
| Drive type | Direct drive |
| Carburetor | McCulloch |
| Air filter | Flocked wire-screen element |
| Ignition | McCulloch flywheel magneto with breaker points |
| Ignition timing | Fixed |
| Breaker-point adjustment | Points set to begin opening with timing pin inserted |
| Flywheel-to-coil air gap | 0.011 to 0.015 in. / 0.27 to 0.38mm |
| Original spark plug | Champion J8J |
| Spark-plug gap | 0.025 in. / 0.63mm |
| Crankshaft main bearings | Ball bearings |
| Starter | McCulloch automatic rewind starter |
| Chain oiler | Manual |
| Fuel-tank capacity | 1.6 US qt / approximately 1.5 liters |
| Recommended fuel | Regular gasoline |
| Factory fuel mixture | 20:1 with McCulloch two-stroke oil |
| Alternative period mixture | 16:1 using SAE 30 non-detergent oil, according to the saw’s instruction plate |
| Chain pitch | .404 in. |
| Original chain type | McCulloch Pintail |
| Guide-bar range | 12 to 36 in. / 30 to 91cm |
| Chain-oil capacity | Not found in available specifications |
| Standard color | McCulloch yellow enamel with black air-filter cover |
Interesting facts about the McCulloch 1-70
The “70” in the model name does not indicate engine displacement. The 1-70 is an 87cc saw, making it considerably larger than its name might suggest.
Its production run lasted only a little over a year. The closely related McCulloch 1-71 was introduced in June 1960, shortly before the 1-70 was discontinued.
The original fuel instructions are preserved on the pictured saw. They call for one pint of McCulloch oil in 2½ gallons of gasoline, producing a 20:1 ratio. An alternative mixture of one pint of SAE 30 non-detergent oil in two gallons of gasoline gives a much richer 16:1 ratio. These are historical instructions and not necessarily the best guidance for modern fuel and two-stroke oils.
The 1-70 was direct drive and used a manual chain oiler. There was no chain brake, automatic oil pump or anti-vibration system, so operating one is a very different experience from using a modern 87cc professional saw.
A McCulloch 1-70 preserved by the Finnish Forest Museum is stamped “1-70/80” underneath. This likely reflects the close relationship and shared components between the direct-drive 1-70 and the gear-drive 1-80.
Surviving saws may carry replacement bars, chains, bumper spikes, caps and other service parts, so individual examples do not always match period catalog illustrations exactly.
