Elegent Scroll Frame Skeleton Clock

[Kim]

Strikes, OK, picket lines and burning trash barrels, not so much....oh wait...

A square broach would work as well, but I do like your ingenuity.

Interesting... I considered a broach, but it seemed hard to do when in a blind hole.  Would you have to make a series of broaches, each one slightly larger?  Like a Taper Broach, a Plug Broach, and a Bottoming Broach? 

Kim

[bent]

Rotary broaches work in blind holes...but you need to find one in your size...and I don't think even rotary broaches will "bottom"

https://www.mcmaster.com/products/broaches/rotary-square-broaches~~/

[uuu]

Another rotary broach - in kit form, so considerably cheaper:

https://www.hemingwaykits.com/HK2570

Wilf

[Dave Otto]

I made the rotary broach from Hemingway, it works quite nicely.

Dave

[kvom]

I meant broach a through hole and then bind to the rest of the key body. 

[Kim]

A Rotary broach?
I've never heard of such a thing.  That's fascinating!  How does that even work?!?  Is it like drilling a triangle-shaped hole with a round bit?  I've done that before, though not on purpose 

Does the Hemingway kit only broach one specific size? Or is it adjustable?

I meant broach a through hole and then bind to the rest of the key body.

Ah!  That makes sense! 

Kim

[crueby]

The Hemmingway page gives a description of how they work. Part magic, part technology...

[Dave Otto]

The rotary broach puts the cutter at a slight angle to the work piece. In the lathe both the work piece and cutter rotate together, in the mill both the work piece and cutter are stationary and only the cutter body rotates. You need a starting hole that is the finished size of the hex or square with a lead in chamfer, the cutter basically nibbles out the corners and pushes the swarf to the bottom of the hole. You have to make a cutter for each size that you want to broach. If using a commercial rotatory broach you can purchase the cutter for that tool. I have successfully broached a 3/32" square hole in steel using a high speed tool that I ground on my D-bit grinder.

Dave

[cnr6400]

  Just mentioning it for completeness - if a square or rectangular blind or thru hole is ever needed in steel of any hardness, EDM is an excellent way. An inexpensive EDM can be built in the home shop easily. I built one to the Ben Fleming design back in 2009. Worked very well at the time. I haven't used it in a while due to health issues but I expect it would fire up and run like a champ if needed today. Simple and durable machine and very capable of accurate work. The type and number of shapes to be cut are infinite. Ordinary copper bar , rod and sheet make great electrodes. I used Valvoline EDM specific dielectric oil which has almost no odor at all and flushes and filters beautifully, almost no smoke off it while cutting. 

[Dave Otto]

Just mentioning it for completeness - if a square or rectangular blind or thru hole is ever needed in steel of any hardness, EDM is an excellent way. An inexpensive EDM can be built in the home shop easily. I built one to the Ben Fleming design back in 2009. Worked very well at the time. I haven't used it in a while due to health issues but I expect it would fire up and run like a champ if needed today. Simple and durable machine and very capable of accurate work. The type and number of shapes to be cut are infinite. Ordinary copper bar , rod and sheet make great electrodes. I used Valvoline EDM specific dielectric oil which has almost no odor at all and flushes and filters beautifully, almost no smoke off it while cutting. 

I purchased the bare PC board and book, but that is as far as I ever got with that project.

Dave

[Kim]

Very interesting!  I'll have to keep the rotary broach concept in mind.  As well as EDM! That sounds like a whole different rabbit hole to climb down! 

Kim

[Kim]

Next, I made four feet. These will attach to the (as yet unmade) wooden base for the clock.  The feet have some fancy bead and cove work on them.  I chose to do this with a series of form tools.  These were all made from 3/8” W-1 drill rod where I milled a bit off the top and bottom to make them have a nice flat spot for the shape I want to make.    Then I used various mills to create the geometry.  Except for the center one (convex radius), which I shaped freehand on the grinding wheel, comparing it to a radius template.  Then they were hardened, tempered, and honed a bit.


I made the feet from 1” 303 stainless rod.  I started by making the basic shape with a standard tangential tool, then a grooving tool for the back part.


Then I started applying my form cutters, one at a time.  I started with the 3/16” bead in the middle.


Then the 1/8” cove on the top (this will be the top of the foot).


And the 1/8” quarter round on the bottom (that’s 1/8” radius, right?).


Next, I drilled and tapped a 1/4-20 thread in the center, then parted it off.

After making all four feet this way, I made an arbor with a length of 1/4-20 threaded rod sticking out the end.  I threaded the feet onto this to polish them up using little files, sandpaper, and some fine Craytex.


They came out pretty nice.  The two on the left are upside down (i.e. you’re looking at the bottom), and the two on the right are right side up.  I will be gluing some felt disks to the bottom of the feet.  And the top of the feet will be nestled up to the underside of the base, so I didn’t spend a lot of time polishing those surfaces.


Wilding’s plan shows a simple countersunk hole through the feet for you to use a wood screw to fasten them to the base.  I chose to use the 1/4"-20 threads.  I’ll be using these short 1/4" hanger bolts to attach them to the base.  With the threads, I’ll be able to use the feet to level the clock.  That felt like a good deal to me, and it really wasn’t much more difficult.


The only part I have left to make is a travel lock for the pendulum.
And a ton of finishing, of course…   
Kim

[crueby]

Great start on your scale model of the Parthenon!   Kidding. The feet look great!




You mention Craytex. Whats that?

[Krypto]

Maybe Cratex?

Cratex is an rubberized abrasive.  It's very handy for polishing and seems to last forever.  The sticks are handy for "engine turning".

https://www.amazon.com/Walthers-SceneMaster-Cratex-Abrasive-Block/dp/B0050J3Z2Q

I've been using the above block for years.  Also got the stick sample pack.

[Kim]

Yes, I meant Cratex.  Sorry 

Spelling isn't exactly my long suit 

I purchased some square and some round sticks of various grades of Cratex at one point. It does work very well for polishing.

Kim