odd drill bit?

[OlioReader]

about 30 inches long, 3/8 round.  4 inch single flute with both edges sharp.  Almost looks hand made but the other end has tabs that look to go into a handle.

[Smoggy]

Could you not provide a picture of the whole item?

It looks like it may have a coolant channel running through it, difficult to tell from the pic. if it does, given the other dimentions, I'd suggest its a deep hole drill such as is used for boring gun barrels and the tip has been broekn off. Alternately it may not be a drill bit at all, it could well be hand made, we engineering types make all sorts of wierd gizmos at times and if so....there's no telling what the makers intentions were!

[OlioReader]

here are the pics I have.  There isn't a cooling channel that runs the length.  One of the pictures shows a second one that is made out of 1/4 round and it has a break in it that was repaired with looks like a brass solder.  It is still a bit wobbly so if the fix was successful, it wasn't used in high torque situations....  I got these at an estate sale with a bunch of other steel dirt cheap.  this guy had tons of large taps, dozens of files, cold chisels, antiques wrenches and planes..  I couldn't figure out the hobby that made him collect such a varied shop

[Kozzy]

Ayup, looks like a bit for "gun drilling"---that's a process of deep bore drilling and only uses the word "gun" because that was the common early use.  They're generally fed through an alignment sleeve due to length and often both the part and the bit are rotating in opposite directions which gives a straighter hole.  Most modern versions have coolant holes down the center. The flutes of most modern versions are longer because the high-pressure coolant ejects chips back down the flute from the cutting edge.  

Here's some modern carbide tipped gun drills, one in an adapter to inject the high pressure coolant 

[OlioReader]

That is probably it.   I bet these were homemade and application specific... 

 

Thanks!

[Smoggy]

Yep, they do look homemade as they usually have one straight flute and it is only a quarter (90 deg) of the drill not half as in the first pic. the end geometry is also normally offset for barrel drilling. There is one more possibility, still gunsmithing.....the picture in our original post could be,a rifling reamer with the end broken off, the cutter would sit in the flat area and cut a single groove.

[SmoothBore]

My wild guess, ... is that they were used to drill the aligned holes, necessary to assemble "Windsor" chairs.

In that application, there is no need to evacuate chips from a "deep" hole, ... thus, a short fluted section is all that's required.

 

.

[JHCC]

2 hours ago, SmoothBore said:

My wild guess, ... is that they were used to drill the aligned holes, necessary to assemble "Windsor" chairs.

In that application, there is no need to evacuate chips from a "deep" hole, ... thus, a short fluted section is all that's required.

Interesting idea, although Windsor chairs were traditionally made using "spoon bits" -- bits with a straight semi-cylindrical fluted section for most of its length, terminating in a half-dome shape at the business end. These almost always had the tapered square section at the end to fit in the chuck of a hand brace. They're still made, for that subset of woodworkers who still make Windsor chairs by hand.

[gote]

Why would that type be used today? Are they in any respect better than the auger bit. I have a couple lying somewhere, inherited from my grandfather but I have never used them. Is it because they cut both ways?

[swedefiddle]

Good Morning,

Very similar to some of the Tools in the 'Mastermyr Find'

 

The 2 spoon shaped pieces in the lower right corner are Drill Bits, that cut clockwise or counter-clockwise equally. I have used one to drill a hole in a 2x4. A perfect round hole in about 8 rotations, by hand. There is a cross piece you turn with both your hands, while pushing with your shoulder on a thrust plate. The Vikings were not ignorant. This collection is placed about 1025AD. A lot of the Tools in the Mastermyr Find are recognizable with what we have in our Blacksmith Tool Box, today

[gote]

Yes the Mästermyr artisan (He seems to have been both smith and carpenter) would probably find a spoon bit more efficient to make. The question is Why would a present day maker of a windsor chair use a spoon bit? Is it because they can be made for tapered holes? The Mästermyr ones are obviously tapered.

[ThomasPowers]

One reason would be to leave tooling marks identical to the originals for high level repair or replication work.

[SmoothBore]

On 2/21/2017 at 4:48 AM, gote said:

Why would that type be used today? Are they in any respect better than the auger bit.

"Better" ... is dependent on your desired result.

The bits in the photo appear to be "blind hole" bits, ... intended to make a flat bottomed "pocket", rather than a "through" hole.

 

Spoon bits are used in chair making, in order to create "pear" or "bell" shaped blind holes, ... ( By rotating the driven end of the bit in an eccentric pattern. ) ... that are bigger at the bottom, than at the point where they enter the wood.

This allows space below the surface, for a short wedge to expand the end of the male portion of the joint, as it is forced into the blind hole.

Resulting in a "knob" on the end of the male portion, embedded in the blind hole.

( Think of the way a properly installed wooden hammer handle is wedged to fill the tapered cavity in the hammerhead. )

 

Since the making of wooden chairs predates the availability of modern hardware and adhesive materials, ... those early chair makers needed to be particularly clever in their choice of materials and techniques.

Joinery, of the sort mentioned above, ... and the practice of embedding well seasoned components into "green" counterparts, ... ( To effectively "shrink fit" a joint ) ... were some standard techniques.

A chair assembled in this fashion, would actually "tighten up" as it aged.

 

 

[Alan Evans]

I do not think they are for metal...the cutting edge is too fine.

I do not think they are for chair making...they are too long and too small diameter. 

They look similar to the augers my father used through a hollow tail stock device on his wood lathe to drill things like the cable way for a standard lamp or table lamp...the standard lamps poles were always made in two pieces because the lathe bed was not long enough to do it in one. 

The augers kept central...most of the time.

If I can dig through my storage junk in his workshop I will check and photograph one.

Alan

[gote]

What you write makes sense Smooth Bore. I will take a look at my own in the weekend. They are called "pinnstol" in Swedish which translates to 'stick chair' and are nearly always of the 'fan back' type.

[Alan Evans]

I did manage to clamber through to the lathe, it is buried under the interior trim panels of the old discovery I am rebuilding!

The auger has the same cutting edge as OlioReader's, so I guess it was for the same purpose.

I can't get back to edit my earlier post but a bit is missing...re the too small  diameter...it should have ended "even for the Windsor spindle back joints" 

The augers I have seen used for the spindle backs all had a single flute but included a taper twist screw point to locate centre and pull them in. The tapered screw tips work with side grain but aren't much good for the end grain boring that these lathe / spindle bits  are designed for.

Alan

 

 

I even  found the hollow centre device that it worked through.

 

[Alan Evans]

3 hours ago, SmoothBore said:

Snip...

Since the making of wooden chairs predates the availability of modern hardware and adhesive materials, ... those early chair makers needed to be particularly clever in their choice of materials and techniques.

Joinery, of the sort mentioned above, ... and the practice of embedding well seasoned components into "green" counterparts, ... ( To effectively "shrink fit" a joint ) ... were some standard techniques.

A chair assembled in this fashion, would actually "tighten up" as it aged.

 

 

We have a green Oak sprung and Ash framed sofa  made by an old school friend of mine using that technique. 

There was a revival of interest in the green woodworking techniques of the old Windsor chair bodgers a few years ago over here. Lots of courses sprung up alongside the survival type Ray Mears outdoor adventures. I made various bits and pieces of pole lathes and froes and the like for friends who became interested.

The main chair making industry centre was not actually in Windsor but High Wycombe. The Bodgers turned the spindles green on pole lathes in the woods and stacked them up to season for a few months after which they were then taken down to the factories for assembly. The  big trees were split and seats adzed out, drilled and assembled whilst still green.

My father was a furniture designer-maker all his life. As his eye sight started to fail he moved over to lathe work spindle and bowl stuff which he could feel as well as see...the cabinet joint precision became impossible...in fact I am looking at one of his stools now.

That one has through tenons and wedges in the seat. Wedges always at right angles to the grain around the socket!

 He knew some of the old boys involved in the Windsor chair making Industry...or rather its Arts and Crafts revival from the turn of the century. 

One of the "wrinkles" I remember him passing on from them, was to use a bit of boiled potato in a failed shrink joint as a glue! It works well. I used it recently to fix the wooden knob on the end of my Lee reloading press lever, which kept coming off mid-press...it has stayed on ever since, at least six months.

Alan

[bigfootnampa]

It is a turners tool designed for drilling centered holes.  It is supposed to self center as it drills and is commonly used for things like drilling lamp stands to create a hole for wiring.  These are still being manufactured and I have one in my truck.  These are sometimes called lamp augers.  They are usually 3/8" diameter, which fits a standard threaded wire tube.