Pump drills I made back in the 70's

george wilson

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Yesterday I began a new pump drill for a friend who is a craftsman in the historic area in Williamsburg. I make the 1/8" shank spade point drills also. The noses of these drills have a tapered thread,which I used to make by slowly backing up the cross slide while cutting the thread. The lathe I used then was slower. My Hardinge HLVH goes too fast to do that easily,but I like the Hardinge so much,I didn't bother to do the threads in my large lathe which will do 30 RPM. Should have,though. I did manage to finally taper the thread cut. I have OLD threading combs that I can run over the threads with and smooth them out. thread combs were used years ago to freehand cut threads by learning to move the comb at just the right speed BY HAND to cut threads on a non thread cutting lathe.

These drills were scanned off slides I made years ago. I used to get paid to give slide lectures,so I made slides instead of pictures.

I enjoyed making fancy moldings and other nice details. Most pump drills were very plain.

PICT0001.JPG PICT0009.JPG PICT0008.JPG
 
That's some pretty work George.

"Billy G
 
George
They look lovely but I'm going to have to confess my ignorance here.
I've never heard of a "pump drill" and have been trying to think what it is all morning (its 12.50pm here in Aus atm)
Now that I've seen you pictures I still can't work it out.
Can you explain what it is and how it works please?
I'm assuming its some sort of hand operated drill for drilling small holes in wood?
This has me intrigued.

regards
bollie7
 
Thats what they are bollie 7. they would be wound up making the handel rise and the string wrap around the shaft. When the handel is pushed down the shaft rotates, the opperator would time the pumping action of his hand to let inertia rewind the string the other way, then the whole process would start over. The drill shaft would rotate both directions, so the bit end would resemble a spade bit, insted of a helical cut drill bit wich are so common today.
 
Pump drills are most often used for drilling small,not very deep holes in metal. They can drill holes in wood,but as soon as the wood fibers bog down the bit,the flywheel can no longer rewind the leather thong,and it stops working.

Actually,these drills can do extremely accurate work. They can be run slowly,and tilted to move the hole back to where you want it to be,as long as the spade drills' lips have not yet fully entered the metal. I accurately drilled a dividing head disc with a pump drill. I have posted it here,but will post it again in a new thread.

Mostly,pump drills were used in silver smithing and watch and clock work.

When I was working in costume in the musical instrument maker's shop, my least favorite 18th.C. tools to use were drilling tools. The pump drill,however,was efficient,easy to use,and very accurate(after you master its use!). The wooden brace,gimlets,spoon bits and 18th. C. type spade bits (center bits)were not my favorites.
 
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I love these... I am teaching high school metalworking and these would be a great project. I like when the students build something that the can use rather than "shelf-sitters"
 
You don't have to make the flywheels fancy. A plain disc will work. Don't make the discs too heavy,or the drill will run quite slowly from inertia. 2" diameter and 1/4" thick solid brass will do nicely for the range of small holes these drills will do.
 
It its hard to see in the group picture of the pump drills,but they are all a little different. I do not make things exactly the same(unless I am being paid to do it,as in my toolmaking job). The flywheels are not all the same diameter. (depended upon the brass disc I happened to pick up.) More importantly,the tops of the pump drills have different features. Actually,the noses do too.

I'll photograph the one I'm making now. My camera doesn't auto focus well,and with a grand daughter's college stuff draining me,I don't want to buy a better one right now. I'll have all of you thinking I'm poor here ! No,just priorities.
 
Back in the late fifties, I was a jeweler's apprentice. The old timers used and swore by bow drills, also called pump drills and were sure that they were more precise than electric drills. I think they were probably right. Tom
 
This is a bit off thread, but since you (George) mentioned "thread combs" more commonly refered to as hand thread chasers; I have pretty much a whole set of them, and mainly use them to clean up damaged threads in the lathe, using a jury rigged rest, similar to what one would use in a wood lathe; you can clean up threads that may not even run perfectly true, and as George points out, it is possible to cut threads from scratch, and this was commonly done in brass work back in the day.
The trick to preforming it is getting a start at the end of the part, where one tooth enters the trace of the one before it. I hold the chaser at a bit of an angle to the part, not parallel to it, and with the part rotating, swing the handle end of the tool to the right while pushing it into the part; this helps to get the first traces going, after thatadditional cuts are taken with the tool face parallel to the part, taking scraping cuts until the depth has been reached; in brass it is pretty easy to do, but can be done in steel as well. A friend told me that an old man made him a special nut for the rods on a Stanley Steamer, using nothing more than a hand lathe and hand chasers; he first made a female thread gage to fit the sample nut, then made a new nut using an internal hand chaser and using the gage to fit it; he said that the gage and nut fit as nicely as any that would be made on an engine lathe.
The main ingredient was skill!
 
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