Goodell Pratt Hand Drill Repair

[Russell Talbot]

Hi All

I have been repairing a Goodell Pratt 5 1/2 B hand drill that belonged to my father and to his father. The objective is not to make it like new, that would lose it’s history, but to make it into a usable tool.

Unfortunately I am having trouble with the last bit (OK I admit it’s the last bit because it’s the most difficult and I left it until last).

I have had some great help from members of the UK workshop forums but these drills are quite rare in the UK so I am posting here to see if anyone can help.

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I’ll show you what I’ve done so far.

The main handle on the drill had clearly been repaired before and the ferrule had been redrilled and had a "pin" retaining the handle. The pin was six strands of copper wire with nasty sharp ends.

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I took the pin out and removed the handle. I discovered a piece of wood had been let into the handle and the extra hole through the ferrule had been drilled through the threaded iron of the drill. Unfortunately it had missed.

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The metal between the original and the new hole had also cracked.

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After some thought I decided that this had to be fixed. My objective is to make this a usable tool and this would eventually have broken. I cut the old thread off and drilled the frame with an 8mm hole. I found a bolt with the same thread as the original and turned that down to 8mm and loctited the two together.

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The next problem I tackled was that the crank knob wouldn't rotate. I thought this was probably due to rust on the shaft. I drilled off the riveted over end and removed the knob. I hit a big snag here. I thought the shaft was tight in the knob because it was rusty. It turned out that the shaft was too short because of previous attempts to tighten up the riveting. That had also swollen the end of the shaft inside the knob, so the knob split as I tapped out the shaft. I glued it back together. I used superglue because the low viscosity meant I could get it in without having to remove the small brass ferrule from the knob. I turned a new shaft and re-riveted the knob in place.

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As I mentioned the main handle had already been repaired once but the new bit of wood disintegrated as I took it to pieces. The first task was to clean up the hole in the handle and make it round.

That was easy once I'd worked out how to hold it in the lathe.

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To be continued.

Russell

[Russell Talbot]

The next step was to make a wooden threaded insert for the handle. I tried making a tap from a bolt with the right thread but couldn't cut a thread in the end grain. I decided to use a dremel type tool to cut the thread. I made a special cutter for the tool,

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and a special tool holder for the lathe.

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Here are the bits,

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and this is how they went together.

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Next job was to plug the surplus holes in the ferrule. I brazed brass screws into the holes and then filed them flat. There’s a plug in this photo just to the right of the hole.

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The handle is back on and there is a cross drilling for a pin.

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Then I made the missing part of the chuck.

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I had to deburr the socket in the drill shaft but it fits in the chuck nicely.
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To be continued

Russell

[Russell Talbot]

Then I put all the bits together and it drills holes.

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I made a new side handle based on measurements I got from helpful people at ukworkshop.co.uk. Any inaccuracy in the knob (ferrule is a bit short) I blame on my incompetence.

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This is where I’ve got to.

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Observant readers may have noticed there is still a problem. The low speed pinion is missing.

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I have been considering trying to make a pinion. I had never made a gear before but since I got to this stage I have made a few bits of tooling and experimented with cutting spur gears. Unfortunately mitered bevel gears are the most difficult to cut and the more I have read, measured and calculated the more difficult it looks. One problem is that the gears aren’t made quite as the books I have read suggest they should be, another is that the methods suggested for making bevel gears in the home workshop approximate the tooth form and I’m not clear whether these will mesh satisfactorily with the original gear. That makes it very difficult to decide exactly what the gear should look like.

All that brings me to the point of this post. Does anyone have a spare slow speed pinion for a Goodell Patt 5 1/2 B. Any condition would be good – I could try and copy a broken one or one with missing teeth.

I have considered buying a drill just for the part but the drills I have seen are in better condition than this one was and I don’t want to destroy another drill to repair this one.

All suggestions will be gratefully received.

Russell

[Jim Koepke]

Howdy Russel and welcome to the Creek.

Your rustoration is looking very good.

One of my junk drills has a mechanism like this. Will take a look to see if it is still there and a Goodell Pratt. It has been picked for parts in the past. Not sure if it is still in the junk pile or if it was sent to another member in need.

jtk

[Peter Christensen]

If all else fails you could buy another in good condition, copy the gear on it and then sell it again. This is one of those occasions where the work to restore the tool can't be justified monetarily, only sentimentally.

[Russell Talbot]

Thanks Jim, I'll keep my fingers crossed.

Peter, you're absolutely right, it is only sentimental. It's a good idea to buy and sell on again - I'll think about it - one snag is that they are so rare in the UK that I might have to pay transatlantic postage twice on the whole drill.

Thanks for taking an interest.

Russell

[Mike Hutchison]

Just want to chime in w/ thumbs up on what you've done thus far

[Russell Talbot]

Thanks Mike, glad you approve.

Russell

[Jim Koepke]

Hi Russell, sorry for the delay in getting back to you. It appears that drill may have been sent to someone who needed some parts. My recollection after thinking about it a bit more is that it may have been a Yankee model.

Good luck with your rustoration.

jtk

[Russell Talbot]

Jim. Thanks for looking.

Russell

[Kevin Yarger]

Russell, looking at my example of this drill, the two gears are the same, so you have a gear to copy. It makes sense from a manufacturer's standpoint, that the two gears would be the same.

Nice job, that drill is looking good!!

[Rob Paul]

My low speed pinion gear is different from the high speed one (steeper bevel, less teeth, smaller diameter)
[This is on a drill labelled as a Goodell Pratt 5-1/2 ]
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If you can buy or borrow another drill, you should be able to use an existing gear to use as a form to cast a bronze gear for yours

[Richard Darjes]

I too own this drill, but mine was almost complete when I found it. It was missing the springs for the chuck and may have sat unused for many decades because of that. I got advice in the early 2000's on where I could get the right size springs - cheap plastic mechanical pencils have a smaller diameter spring than ball point pens.

I have to disagree with Kevin Yarger, the two gears on my 5 1/2 Goodell Pratt hand drill are very different and are not interchangeable. On a slightly different point, my drill is equipped with ball bearings at the bottom of the main frame of the tool. It also has a patent date of 1896. In your pictures, it doesn't appear that your drill is equipped with these ball bearings (there is a small red spacer that is hard to miss at the bottom of the main frame). If you do not have the ball bearings then your drill could be older than 1896.

Good luck in your search for a replacement gear.

[Richard Darjes]

Of course, now I look at your pictures enlarged and I see the red spacer I was referring to! So you know your drill was made some time after 1896. Goodell Pratt was bought by Miller Falls at some point (early 1930's?) so you have a time frame at least.

I am obviously not adding much to the discussion here!

[Jim Koepke]

I too own this drill, but mine was almost complete when I found it. It was missing the springs for the chuck and may have sat unused for many decades because of that. I got advice in the early 2000's on where I could get the right size springs - cheap plastic mechanical pencils have a smaller diameter spring than ball point pens.

Though it is getting harder to find people smoking from whom to bum dead lighters, they also have smaller springs than pens or what can commonly be found in hardware stores. BIC lighters have two springs, one under the flint and one under the gas lever. Most of the cheaper disposable lighters only have one spring.

jtk

[Russell Talbot]

Kevin, Rob, Richard, Thanks for taking an interest. I think the gears are different - from the pictures I've found on the web one has 21 teeth and the other has 20 teeth. From my own measurements I think that the angles are different too.

Jim, Richard - I'm obviously too much of a hoarder. I needed some springs for the chuck too - but when I chuck stuff out I save useful bits like springs - so I looked in the tin marked springs and found three - I've no idea what they came from.

Thanks all for taking the trouble to comment.

Russell

[Kevin Yarger]

Guys, I guess I am better at lurking than posting!! You're right, the gears are different:
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[Russell Talbot]

Hi Kevin

But you inspired a couple of other people to comment.:):)

Russell

[Russell Talbot]

I am shocked to see how long it is since I last reported progress on this. There has been a lot of procrastination going on.

I set up a search on eBay which only found me drills that were in better condition than mine. I read up on gear cutting and mitred bevel gears in particular. All that revealed were that these were not theoretically correct gears.

So having exhausted all avenues of procrastination I decided to try making a pinion. I decided to try making one in plastic first as it would be much quicker to machine and it would be an experiment.

I measured two angles from the drills handwheel. One was the angle the top of the teeth made with the axis of the drill and the other was the angle the bottom of the gaps between the teeth made with the axis. Because of limited space around it I had to make a sort of mini bevel gauge but I ended up with angles of 39 degrees and 28 degrees.

I made a gear blank on the lathe with an angle of 39 degrees and setup the milling machine to cut 20 gaps between the teeth at an angle of 28 degrees using a home made dividing head (another product of procrastination) which used a lathe changewheel to index 20 positions.

At this point I had to confront the main problem that had been putting me off this job. What shape should I make the gaps between the teeth. Best approximation methods for home cutting of bevel gears suggest three cuts for each gap would be needed so I decided to make a cutter the shape of the smallest part of the gap using the other pinion as a model. At this point I realised that the gaps between the teeth are parallel sided and the wider gaps are created by deeper cuts at the larger end of the pinion so only one cut should be needed.
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I made a cutter out of silver steel and mounted it to an arbour and cut the teeth so that the gaps between teeth were about the same size as the teeth.
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The only remaining difficulty was the diameter which was difficult to measure. It turned out to be too small - but since it's tapered I could make it seem larger by removing material from the small end and much to my delight it actually meshed quite well with the existing gear although it was now too thin.
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I made a second one using the same technique but using measurements from the first attempt. This time the teeth seemed to mesh a bit too deeply so I skimmed the top of the teeth in the lathe. It fitted reasonably well and the drill worked.


I have assumed the missing gear was originally made from cast iron as if it were steel it wouldn't have broken so I bought a piece of cast iron and made another gear blank.
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I hardened and tempered the home made cutter and tried again on the milling machine.
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Then I cut the slots on the back to engage with the dogs on the drill. Can you spot the mistake here?
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Then I assembled the drill.

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It works. I drilled a few holes using both speeds. Success. I'm really pleased with that.:):):)

Russell

[Frederick Skelly]

That's very cool Russell. I'll bet it was very satisfying to take on that challenge, make the gear and then see it work so well. Good for you!
Fred

[Tad Englund]

Russell, I just bought one of these and it is missing a couple of things. The side handle (like the one you made. What size are the threads? I get a bolt to match I hope (I don't have a metal lathe). The springs in the chuck are also missing. Do you know what size they are and how long.
Thanks in advance,
Tad

[Russell Talbot]

Russell, I just bought one of these and it is missing a couple of things. The side handle (like the one you made. What size are the threads? I get a bolt to match I hope (I don't have a metal lathe). The springs in the chuck are also missing. Do you know what size they are and how long.
Thanks in advance,
Tad

Hi Tad

I found a bolt to match, but I don't know what it came from, it measures 5/16 with 20tpi. I suppose there is a possibility I found a worn 8mm x 1.25mm bolt.

I had to have a couple of goes at the springs. First I used three that looked the same but the jaws didn't close evenly. I eventually bought a 100mm length of spring 3.18mm (1/8) diameter with 0.5mm wire diameter off ebay and cut three matching lengths of that. I used the longest length that I could fit into the holes in two jaws and still squeeze the jaws together. It should be possible to calculate that by measuring the depth of the holes in the jaws and working out how many coils will fit in the two jaws but I just used trial and error.

Good luck with finding the bits.

Russell

[steven c newman]

Springs out of three Bic Lighters should also work.....the ones under the flint.

Millers Falls liked to use regular, off the shelf hardware sizes....rather than go with what Stanley used. So...SAE bolts should fit...