As recorded in here:
https://www.ukworkshop.co.uk/forums/north-bros-1003-bench-drill-dismantling-t102897.html
... 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)
[youtube]sszw0UVyHOU[/youtube]
Inspired by Rhytolith’s article:
http://www.timetestedtools.net/2016/08/30/north-brothers-yankee-no-1003/
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).
cheers
Nabs
North Bros took out a number of patents to protect their bench drills, listed below. Most of the innovations are described in US1103783
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US1103783.pdf
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.
ratchet
(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).
chuck
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 )
https://docs.google.com/viewer?url=pate ... 073500.pdf
US1087794A 1914-02-17 (drill head)
https://docs.google.com/viewer?url=pate ... 087794.pdf
US1103746A 1914-07-14 (relieving the guide block of pressure)
https://docs.google.com/viewer?url=pate ... 103746.pdf
US1103782A 1914-07-14 (bench drill)
https://patentimages.storage.googleapis ... 103782.pdf
US1103783 1914-07-14 (main description, including automatic stop)
https://docs.google.com/viewer?url=pate ... 103783.pdf
US1103784A 1914-07-14 (two speed - model 1005 only)
https://docs.google.com/viewer?url=pate ... 103784.pdf
US1103785A 1914-07-14 (automatic stop, adjustable)
https://docs.google.com/viewer?url=pate ... 103785.pdf
https://www.ukworkshop.co.uk/forums/north-bros-1003-bench-drill-dismantling-t102897.html
... 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)
[youtube]sszw0UVyHOU[/youtube]
Inspired by Rhytolith’s article:
http://www.timetestedtools.net/2016/08/30/north-brothers-yankee-no-1003/
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).
cheers
Nabs
North Bros took out a number of patents to protect their bench drills, listed below. Most of the innovations are described in US1103783
https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US1103783.pdf
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.
ratchet
(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).
chuck
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 )
https://docs.google.com/viewer?url=pate ... 073500.pdf
US1087794A 1914-02-17 (drill head)
https://docs.google.com/viewer?url=pate ... 087794.pdf
US1103746A 1914-07-14 (relieving the guide block of pressure)
https://docs.google.com/viewer?url=pate ... 103746.pdf
US1103782A 1914-07-14 (bench drill)
https://patentimages.storage.googleapis ... 103782.pdf
US1103783 1914-07-14 (main description, including automatic stop)
https://docs.google.com/viewer?url=pate ... 103783.pdf
US1103784A 1914-07-14 (two speed - model 1005 only)
https://docs.google.com/viewer?url=pate ... 103784.pdf
US1103785A 1914-07-14 (automatic stop, adjustable)
https://docs.google.com/viewer?url=pate ... 103785.pdf
