Dating GMF bench grinders and electric motors

This is all the information I have with regard to dating GMF tools and equipment.

Bench Grinders

Rowan sent in some interesting information regarding dating the GMF bench grinders. He was looking at the capacitors and found that some were made by Ducon, which have a date code in 3 numbers stamped into them (w/yy), though of course given the age it can sometimes be illegible or rubbed off. They’re rectangular folded capacitors containing PCBs. Ducon apparently went out of business in 1963, and more modern GMF grinders have cylindrical capacitors in them.

Rowan has a 7″ 1/2hp Industrial grinder with serial number 2121139 that has a capacitor inside with the date code of 1961.

6″ Junior

Nock and Kirby show the Junior in 1954, and it’s featured in the 1959 catalogue and in the 1967 Scruttons catalogue. It’s not seen in the 1977 catalogue and I suspect it was deleted earlier in the 70s.

8″ Senior

The 1966 McPhersons and 1967 Scrutton shows an 8″ Senior grinder.

Mark 3 6″ and 8″ Industrial grinders

These were shown in the 1959 GMF catalogue, along with the 1966 McPhersons and 1967 Scruttons but were not shown in the 1977 listings.

Mark 5 6″ and 8″ Industrial grinders

The 1970s McPhersons show the 8″ Heavy Duty Mark 5 grinders in single (¾hp) and three-phase (1hp).

6″ Handy Grinder

Shown in the 1970s McPhersons. Single phase, ¼hp.

6″ Industrial Grinder

Shown in the 1970s McPhersons. No mention of Mark 3 or 5. ⅓hp single phase unit.

7″ Industrial Grinder

Rowan has sent in some pictures of a 7″ Industrial Grinder with a capacitor inside it that has a 1961 date. This model is also shown in the 1970s McPhersons. Single phase only, ½horsepower. 7x1x⅝” bore.

Here is a photo of a 7-inch GMF industrial bench grinder from the 1980s.

8″ Utility Grinder

Shown in the 1970s McPhersons catalogue. Single phase only, ½hp. Also shown in the 1972 Power Farming magazine.

10″ Maxi Grinder

The 1970s McPhersons catalogue shows the 10″ Maxi Grinder in single phase 1¼hp and three-phase 1½hp variations. The wheels were 1″ and 1½” wide respectively with a 1″ bore. Also shown in the 1972 Power Farming annual.

Handy 125 Bench Grinder

This one was made in Singapore. The GMF Singapore factory appears to have opened in 1976, so I would date this model to no earlier than that.

200mm Senior

Shown in the 1984 Power Farming magazine in single and three-phase. Timothy sent in a picture of his which has a Betts-branded plate (making it post-early-1980s), showing 750W of power:

Here is a photo of a 200mm Senior GMF bench grinder from the 1980s.

200mm Heavy Duty

Shown in the 1984 Power Farming magazine in a Betts advertisement, available in single and three-phase. Stated to be the most popular model.

Hugh sent in photos of one he has that was purchased in 1981 – note the horsepower measurement and pre-Betts plate:

Here is a photo of a 200mm Senior GMF bench grinder from the 1980s.

150mm and 200mm Industrial

Shown in the 1984 Power Farming magazine in single phase only. Says it’s the original GMF grinder updated for the 1980s.

150mm and 200mm Tradesman

Shown in the 1984 Power Farming magazine in single phase only.

250mm Maxi

Shown in the 1984 Power Farming magazine in single and three-phase. Stated to be Australian made. Some plates show a horsepower rating, some in watts! Timothy sent in some pictures of his 240v 250mm Maxi plate, serial 945827:

Here is a photo of a 250mm Maxi GMF bench grinder from the 1980s.

939 watts, which is about 1.25hp. The plate shows Betts, which makes it post-early-80s.

Electric Motors

The 1st May, 1959 catalogue lists the following:

  • Single phase motors – Ventilated Drip Proof Cadet, Captain Mark 1
  • Single phase motors – “Durapruf” totally enclosed Cadet
  • Three phase motors – Ventilated drip proof Cadet, Captain Mark 1
  • Three phase motors – “Durapruf” totally enclosed Cadet
  • Captain Mark 2 – totally enclosed, fin cooled, ball bearing motors, single phase
  • Captain Mark 2 – totally enclosed, fin cooled, ball bearing motors, three phase

The 1959 catalogue states that the Caddie was a then-new range of sub-fractional shaded pole motors and that they had been developed for applications such as air circulating fans and room coolers, fan heaters, oil burners, humidifiers, animated signs and small centrifugal pumps. It was available in a drip proof, a totally enclosed design and in an open bracket design with a choice of sleeve or ball bearings, except for the open design which had sleeve only. Output was up to 1/50hp at 1300rpm but it was also available in multi speed.

The 1959 catalogue also showed a metal disintegrator.

2 thoughts on “Dating GMF bench grinders and electric motors”

    1. GMF closed down decades ago – best bet is to find something comparable from what’s currently available unless you want to go chasing used motors (or the needle in the haystack chance of a new one still kicking around somewhere).

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