Elegent Scroll Frame Skeleton Clock

[wagnmkr]

I knew the frames would look good after you filed them. Excellent job Kim!

 

Tom

[Zephyrin]

very nice result, you put a lot of efforts in these frames !
the tricky bit is knowing when to stop filing, it's like an addiction...

[Dave Otto]

The frames are looking real nice Kim!

Dave

[Kim]

Thank you, Tom, Zephyrin, and Dave! 

Kim

[petertha]

Kim, maybe you mentioned elsewhere, but in your recent aluminum cutting, what type of scroll saw are you using & also what kind of blades? I have a variable speed Dewalt & good selection of 5" jeweler blades meant for manual saw frames but work well in the scroll saw. But thus far I have found cutting even 1/8" 6061 was pretty slow going. The finer TPI cut a nicer finish & control but of course slower. The coarser cut faster but they can get bogged down & kerf can go non-perpendicular around tighter radii. Maybe I'm not as patient. I have played around with speeds & (manual) feeds with some improvement. The cream type cutting tool lubricants help a bit but I'm hesitant to use drip or liquid cutting fluids as its 99% a woodworking tool for me. Somewhere in my travels I was told that the $$ machines like Hegner & that class have better stroke geometry & torque at low RPM whereas others, maybe like mine, kind of fall off. I have seen Clickspring buzz through brass on his (Hegner) & I just don't think I could replicate that. Anyway, not to sidetrack on this subject but your recent metal cutting peaked my interest.

https://www.dewalt.com/product/dw788/20-variable-speed-scroll-saw

[bent]

Those frames have a pretty nice finish along the filed edges, at least to my eye.   

[Kim]

Thanks Bent!

Petertha,
No sidetrack at all! This is what it's all about, for me.  Talking to other people about our hobby!

I have a Dremel variable speed scroll saw (inexpensive, low end). And yes, it is mostly meant for wood working, but I have probably used it more for metal!

I agree with your assessment - the thinner, higher tooth-count blades give you more control, but they break a lot!  In cutting this aluminum sheet, which was 3/8" thick with the two plates stacked together, I found that a wider, lower tooth-count blade worked better for me.  It seemed to cut a little faster than the high tooth count blades.  Not much, mind you, but a little.  Maybe because I was able to put more pressure on the larger blades.  But even at that, they broke far less frequently, which was a big plus.

With the smaller high tooth-count blades (in the 40 tpi range), I'd be lucky to cut 1-2" before the blade broke.  With the thicker, low tooth-count (like 15-18 tpi) I'd get 8-12" of liner cut before breaking, or more likely, just changing the blade because it was getting dull. This was a pretty significant difference to me.

I found that it took me about 5 minutes to cut a linear inch. Though any sharp corners would take lots of extra time, even with the holes drilled in the corner.

My scroll saw allows me to use either type of scroll saw blades, the ones with the pins, or the ones with no pins in the end.  The high tooth count jewelers blades never have pin ends.  I find those much more fiddly to change.  The low-tooth-count blades I was using had pin ends, and I could change them a little faster and more easily.  Another advantage, however small.

The kerf cut by the low tooth-count blades was also much wider, of course.  But in my situation, having a very narrow kerf wasn't important to me. Sometimes it is, but not in this case.

Also, the coarse tooth count resulted in a rougher cut - more scratches that had to be filed out. But again, that wasn't a big problem since I was going to be filing away the last 1/32" anyway to get up next to my pattern line.

Cutting the frames was very slow going.  I did the cutting in 2-3 hour chunks, which is about a standard shop session for me anyway.  When it stopped being fun, I quit and went off and did other things.  But I'm quite pleased with how it came out. And I can see doing the same for the remaining holes in the frame that are yet to be done.

I also found that keeping things to the middle speed range of my scroll saw worked best for me.  Increasing the speed of the scroll saw didn't make it cut any faster and just led me to losing control of the part and having it jump up and down.  Yet another great way to break a blade or damage the work!  You'll note that I've taken the hold-down foot off of my scroll saw.  I have found that the hold-down foot messes up the pattern that I inevitably have glued to the top of my work piece (whether metal or wood) so I never use the hold-down foot.  Maybe that's a bad move, but it has worked well enough for me for many years.

My Dremel scroll saw isn't a very high-end one. It cost ~$100 USD when new (about 25 years ago) but has run well for me for countless hours.  I keep thinking about getting a more high-end scroll saw, but then, the one I have works, so why bother?  Maybe someday!  You're DeWalt is a better machine than mine, for sure!

Kim

[Kim]

With the frame mostly shaped, I went through and, one at a time, drilled and reamed several of the holes that go through both the front and back frames.  There are 6 1/4" holes for various columns that separate the plates.  As I reamed a hole, I would replace the screw with a 1/4" machine screw.  However, I wasn’t satisfied with the closeness of the fit with a standard off the shelf 1/4"-20 screw.  So I made two 1/4" dowels, threaded on each end. These were made from 1/4" drill rod (W-1), and these fit very closely in those holes.  I am very pleased with the registration these provide.


Here’s one of them mounted in place.


I only made two of those 1/4" pins.  For the remainder of the holes I continue to use a standard 1/4"-20 machine screw.  Two registration pins hold the alignment very well. The rest just hold the two plates together.

With those six holes reamed and the new registration pins in place, I drilled and reamed the holes for the barrel and fusee arbors.


I also drilled and reamed the hole for the column at the top that will support the bell.  But none of the other holes in the plates were drilled at this time.

Next, I made some filing buttons.  The ends of the various scroll shapes on the frame need to be round.  If they aren’t round, I think the frame will not look as nice.  So I started making a set of filing buttons for the round feet.  Unfortunately, my lathe died before I could finish them.  They’re close, but need some additional cleanup work.

However, they were far enough along that I could check to see if the filing buttons were right.  And while the filing buttons were correct, one of the feet was not.  Oops…   


According to the pattern on the front, I should be OK.  But clearly, I’m not.  This probably means that when I drilled the hole, I was off by a little bit.  How sad, he said to himself 

I think what I’ll do is shave the filing buttons down a tad to make a circle that will fit within what’s remaining of the foot.  I measured it and it’s about 20 thou that I’ll need to shave off the radius.  I think having the round scrolly things be just a tad small but be round will look far better than having them be closer to the specified size but out of round.

But, before I do that, I need to figure out what was wrong with my lathe.  :'(

The symptoms were that when I went to slart the lathe, it hummed a bit but didn’t turn. I tried it again and still had the motor hum, but no turning. Didn’t seem good.   I went looking all over for anything that was blocking the spindle from turning, but found nothing.  I could turn the spindle freely by hand, so that wasn't the problem.  It had been working just fine moments before, but suddenly, all I could get was this hum!

Then it dawned on me that this sounded like the starter capacitor was kaput. To test my theory, I tried starting it again, but this time I gave the chuck a spin, and sure enough, it slowly started to spin and then was fine.  I considered continuing to use it without the 'self start' but that felt not so good.  I don't know what kind of other damage I might cause to the motor if I run it w/o the starter cap.

When I went and opened up the box on the motor, sure enough, I found that one of the leads to the capacitor had come disconnected!  It's kinda hard to see in this picture, but there’s a little burn mark at one of the capacitor terminals, and the wire that should be connected to it is dangling an inch or two above it. You can see the yellowish insulation around the connector.


The cap itself doesn’t have any burn marks around the housing or blowout vent holes like you see when an electrolytic self-destructs.  It looks like the terminal just broke off.  And the burn mark by the terminal was probably caused by arcing as the two pieces separated.

I considered soldering the terminal back to the spot on top of the cap, but that felt kind of iffy to me.  I’d only have the solder holding it in place – not the best connection really.  It might work for a while, but it just felt like asking for trouble.  So I decided to order a new cap.

I went to the Grizzly site and could order one from them for about $22, plus another $13 for shipping.  But the worst thing was, it wouldn’t arrive till end of next week! At the earliest!     Luckily, I was able to find one on Amazon for $12, free shipping, and it should arrive tomorrow.  It looks like the same thing, same size, etc.  So, I’m going to make the $12 bet that it will fix it equally well as the one from Grizzly.  If it doesn’t work, I’m only out $12. But if it does, I could be up and running tomorrow.  Sounded like a good bet to me.

We’ll see how it goes!
Kim

[crueby]

Great progress on the clock. As for the capacitor, check for burn marks on the shop elves lips - one get hungry and gnawed on the wire?

[cnr6400]

  Ah, the old double ended stud/ dowel combo, eh?    (nice way to do the hold / align on the plates!)

re capacitor zap - any chipmunks or squirrels wandering around with their fur all frizzed up and a stoned look on their faces?   

[Kim]

Thanks Chris and Jeff!

 
I'll be sure to check the shop elves.  Though it would serve them right if they did it! 

We do have a lot of fat squirrels around here.  Maybe we have one less now?  I've also been known to catch a rodent or two in some traps I have spread around the shop.  I understand they like to eat wires!  I know they've gnawed through our AC control wires a couple of times.  The pesky little buggars! 

Kim

[bent]

Our old man's coffee group (ROMEOs - Retired Old Men Eating Out) have been discussing mice in the garage recently; one of us has mice in his car, they chew the insulation and cause random "check engine" lights to appear. 

[Kim]

That's no fun!  My brother had mice who apparently made a nest in the vents of his car and it caused a terrible smell anytime they'd turn on the heat or A/C.  Not a fun problem to deal with!

Kim

[Kim]

The capacitor did arrive yesterday, but it was late enough in the day that I didn’t do anything with it till today.  But after a relatively quick installation, the lathe now works great again!  No more nasty humming sound without the spindle turning.  It just works and starts up quickly!  Yay! 

The blue cap along the top is the new one.


Don’t you love it when the simple thing works? 


So with the lathe working again I was able to complete my filing buttons.  I turned the 7/8” diameter set just a little under sized.  Then I made a set of 3/4" filing buttons, again, making them just a little undersized so that the relative size of the larger and smaller scrolly-circle things were similar.

After hardening the filing buttons, I went to work on cleaning up the scrolly-circles:



More filing! 

Kim

[crueby]

Whew!  Glad it was just the capacitor!