North Bros "Yankee" Bench Drill - how it works

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24 Aug 2015
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As recorded in here:

... I've been trying to renovate a slightly battered North Bros “Yankee” drill (model 1003) - it really is a brilliant piece of design and, despite suffering some serious neglect in the past, I've managed to get it working - you can see it in action here (apologies for the crappy video/sound - you can't get the staff these days)


Inspired by Rhytolith’s article:

I've paraphrased North Bros own word’s (from the patents they took out to protect the drill) in an attempt to summarise the sophisticated features it provides (Rhyotith you are more than welcome to use any of this info in your article if it is useful).



North Bros took out a number of patents to protect their bench drills, listed below. Most of the innovations are described in US1103783



There are a several ingenious features on the drill:

spindle stop
see pic below.
The beveled gear wheel meshes with a pinion mounted on the spindle (17)
The spindle is splined throughout its length and the bevelled pinion has a key adapted to the spline so that it can drive the spindle.

A locking bolt (19) has a projection which enters the spline in the spindle to prevent the spindle from rotating when you want to open or close the chuck.

The lock is turned on or off by twisting the lever (21) from vertical to horizontal.


(see diagram 1)

The head of the drill consists of two cast parts, a carrier (18) that sits on the feed screw (10), and the upper part of the head is a sliding bearing (12) which is held to the spindle by a screw (13) and washer (14) and is adapted to slide on the vertical guide (15) which is mounted on the upper portion of the frame and has a stop (16) to limit the upward movement of the sliding bearing.

The top of the feed screw is a ratchet wheel (17) which engages a pawl (20).
A spring is located between the pawl and the inner side of the socket it is mounted in which forces the pawl to engage with the ratchet mechanism.

The tooth of the pawl is bevelled on one side so that it can be turned to the right or the left to drive the ratchet wheel in either direction. In the mid position (when the lever is vertical) the arm rides up a cam on the carrier and will lift the pawl out of engagement with the teeth.

If the pawl is set to feed the stem forward or backwards, at each revolution of the spindle the screw stem is fed the distance equal to a tooth in the ratchet wheel.

(when the pawl is disengaged, the screw stem is fed the distance equal to a tooth in the larger main beveled gear wheel and this means the drill can be advanced rapidly to or from the work piece).


There is a segment located in a transverse slot in the spindle that receives a small roller, and the upper end of the roller rests against the segment. The roller has two purposes, first it transmits the end pressure of the feed screw to the to the spindle through the segment and second it acts as a cam to reciprocate the carrier:


Jam avoidance

The feed screw is locked to the spindle by a ball bearing mounted in a socket in the spindle (27) and in the socket back of the ball is a spring - the ball is adapted to two notches in the feed screw (on opposite sides).

Under normal conditions the spindle turns with the feed screw, but if the drill should bind in the material then the spindle becomes uncoupled from the drive screw as the friction will be enough to push the ball bearing out of the inside slot of the drive and the drill will not go further until it reengages (and this prevents damage to the drill or bit).

Automatic feed shifter
see diagram below


when the drill is in ratchet mode and travelling downwards (lever pointing to the left) the lever will eventually come into contact with the projection 24 and is shifted to the position illustrated in Fig. 8, causing the arm to ride on the upper wall of the notch (20) (which acts as a cam) withdrawing the pawl from engagement with the ratchet wheel 17, stopping the longitudinal movement of the spindle but not interfering with the rotation thereof.

When it is wished to reverse the ratchet movement, the lever (21) is turned to the position illustrated in Fig. 9, so that the, upper projection (25) of the shifter will be in the path of the lever and, by reversing the rotation of the driving handle the movement of the spindle and screw will be reversed and the ratchet feed will take place on the upward movement.
When the lever comes in contact with the projection 25, it is caused to rotate on the lower wall of the notch on the carrier and the pawl will be withdrawn from the ratchet wheel.

(note it is not obvious why you would ever want to do this - if you place the lever vertically then the ratchet disengages and you can withdraw the drill much faster).

Finally there is the chuck - similar to the spring loaded 3 jaw chuck you find in some old miller falls hand drills, but with the addition of slots in the carrier that receive the 3 jaws and stop them moving from side to side. This is also patented (US952320 - March 15th 1910 (see diagram below).


other patents taken out by North Bros for this drill:
US1073500A 1913-09-16 (bench drill ) ... 073500.pdf
US1087794A 1914-02-17 (drill head) ... 087794.pdf

US1103746A 1914-07-14 (relieving the guide block of pressure) ... 103746.pdf

US1103782A 1914-07-14 (bench drill) ... 103782.pdf

US1103783 1914-07-14 (main description, including automatic stop) ... 103783.pdf
US1103784A 1914-07-14 (two speed - model 1005 only) ... 103784.pdf
US1103785A 1914-07-14 (automatic stop, adjustable) ... 103785.pdf
That's a really great article. Thanks for posting.

I've been considering doing something similar on the "Yankee" 1530, 545, 1545, 555 & 1555 eggbeater and breast drills - but my round tuit hasn't come yet.

Cheers, Vann.
I realise that the audience for in-depth info on old drills made by an extinct US manufacturer is probably quite small, but in the spirit of sharing for future posterity and the enjoyment of tool nerds, here is what I found out about North Bros’ advertising for the 1003/1005.

It shows the art of marketing at its best(worst?) and is an interesting contrast to the aforementioned patents, which are a picture of clarity including pithy descriptions and clear diagrams.

The publishers of Popular Science Monthly and Popular Mechanics have generously made their entire back catalogue available via google books, so we can get a reasonable survey of North Bros's efforts to flog their wonder drill. The earliest advert is from 1915 and the last in 1926 which fits roughly with the likely production dates of 1914-1931,

The marketing men make a lot of the “automatic” mechanism and, fair enough, since the drill does automatically descend without a separately operated down-feed and it also automatically switches to “friction mode” at the extremes of travel or when the drill jams.

It is not true, however, that “the moment the drill begins to cut, the feed automatically changes to Ratchet movement” as the North Bros marketing genius claims in August 1919. Putting the drill in ratchet mode in fact requires the user to twist the small lever on the feed mechanism to the left, and this is no doubt what - in the same advert - the tall pointing man is explaining to the short fellow in the strange hat.

Sanity has returned in 1926 and there is a clear description of what the drill does, although sadly the hat/pointing demonstrators are no longer there and, worse too, this seems to be the swansong for our favourite bench drill as it is its last appearance with subsequent adverts only talking about yankee screwdrivers.

Nov 1916
One of the original adverts - it shows the handy little spanner hanging from the bottom of the screw that attaches the drill to the bench. Inevitably all of these were lost within 15 minutes of unpacking the drill, and apparently North Bros lost their’s too since it is never to be seen again in later adverts!

mVh84HCK-4mKyZRHPi_MTVGPaLt6UoWFVZZRRD0f5xVyzsa9-NLpww bench drill&pg=RA1-PA146#v=onepage&q&f=false

March 1919

TFsQqQCjbOakV9RnAtZEYBn-qjVVjAzkl670W3dyAKgvkGeJWkoBag operates&pg=PA95#v=onepage&q&f=false

Aug 1919

Chtpqp_8pbOJc7WzDYMLdEmNw5OoBzfOK3R5iavyUYrKPaqb_IYPSg bench drill&pg=RA1-PA105#v=onepage&q&f=false

Nov 1926

WRbUEwvkpsGjO0gTCVItTA4rhkoRFweqLtqnzwFdgUU7AGm71nTbjg feed&pg=RA1-PA113#v=onepage&q&f=false
Thanks for this article Nabs, I've found it most interesting and if that makes me a tool nerd so be it. Of possible related interest may be the North Bros No 1500 Chain drill which uses an advancing mechanism very similar to the bench drill. Two patents by George Leopold cover this tool, US 1033712 July 23 1912 and US 1034258 July 30 1912.
In practice the square drive tang of the chain drill is gripped in the jaws of a brace, the chain is wrapped around the work piece and as you crank merrily away the feed mechanism automatically advances the drill bit in exactly the same way as detailed above by Nabs.


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  • Yankee Chain Drill 001.png
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That's a handy archive Nick. The chain drill was still for sale in the McPhersons (Australian) catalogue of 1935, but the Yankee bench drills are not listed there.