OurWorkbench

A SECOND CHANCE FOR A BEST GUESS

To review a little, I'm working on the development of a workstand that holds sewing machines and rotates them easily for restoration and maintenance work. I am trying to find the ideal pivot location for the greatest number of machines.

All machines are a little different in the way they balance. Machines with motors have a little more weight above the bed. One sewing machine might be a little top heavy, another might favor the bottom. Some machines are just about right. The purpose of this effort is to provide the best balance, optimized for the greatest number of machines possible. In other words, maximizing the "just about right" pivot point among the varied and diverse machines.

I've made a different metal swing frame for another workstand that I am currently testing. The second swing frame has a variation in the hole positioning of the uprights.

The new frame and the original are shown below. The pivot shafts have been removed to offer a better view of the uprights. The new frame hasn't even been painted yet.

(Comparing Two Frames)
[ATTACH=CONFIG]549443[/ATTACH]

The first machine to go into the new frame was our Miracle. It's one of our favorites and has a broken wire inside the pillar. The light doesn't work because of it. There are several signs that the short lamp cord got yanked by a previous owner, which broke the wire to the switch inside the pillar. The Miracle's wiring problem needs a separate post.

In the new frame I have tried two older White Rotarys, the model 43 and the model 11. I also tried a Singer 201. I'm just getting started. I have many more machines to try, but already have the sense that this modification will optimize balance for a wider variety of machines. I like it better.

The original swing frame pivot point is 3 inches above the sewing machine bed. The new frame offsets the holes for the pivot point down half an inch, to 2-1/2 inches above the bed.


WHAT WENT INTO MY FIRST GUESS

When I started this thread, the first prototype workstand was already complete. As a result, I had no pictures of the building of it. Building another one gives me the chance to post pictures of some of the steps in making it. And I'm posting some of the research that went into the development of the first workstand too, for completeness of documentation.

Before building the fist workstand, I didn't know very much about the measurements and mounting conventions of the many kinds of sewing machines. And what research I did showed no information on the center of gravity of sewing machines.

I wondered if it was a good idea. Any such workstand device would need to be versatile. If a separate baseboard was needed for every kind of sewing machine, the workstand idea wasn't practical. And, if center of gravity varied too widely, adjustment might become cumbersome. These concerns made me hesitant to actually build the first workstand without knowing more.

Having a rather extensive variety of sewing machines as a resource, I set about collecting measurements. In addition to center of gravity, weight and bed measurements for mounting, I gathered around forty other measurements and specifications, too.


My Setup For Measuring Center of Gravity

I thought to myself that if I could lay a machine down, either on its back or its face, onto a flat board, then the weight distribution of the machine would be transmitted into that board. A flat board can be easily teeter-tottered on two points to determine balance. Where it balances is the vertical center of gravity.

I made a board with inch markings up each side and a baseline to align the bed of the machine. Aligning the bed of the machine with the baseline on the board is crucial.

(Balance Board)
[ATTACH=CONFIG]549444[/ATTACH]

The machine is propped up so that the bed is at a right angle to the balance board. Gentle padding protects the machine.

(Propped Up)
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The pointed blocks, front and back, allow balancing the board by trial and error by repositioning it on the points. It may look a bit precarious, but it really isn't. Not seen in the photo below are two blocks under each side of the board, which only allow a small amount of rocking back and forth. That prevents possible mishaps in the trial and error process of finding the balance point.

(Center Of Gravity)
[ATTACH=CONFIG]549446[/ATTACH]

I did this for each unique kind of machine I could find. From old black machines to the newer plastic ones, the best overview of the machines I could get. For each machine I made a data sheet of information and measurements that I gathered.

(Data Sheet)
[ATTACH=CONFIG]549447[/ATTACH]

I developed a system of defining measurements that is shown in the following two illustrations. Measurements from the data sheets was entered into a computer for study and comparison.

(Sewing Machine Measurements 1)
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(Sewing Machine Measurements 2)
[ATTACH=CONFIG]549449[/ATTACH]

From the data collected I learned two important things.

1) The center of gravity among sewing machines varies up to one and a half inches, possibly more. Finding the ideal spot for the most machines might be tricky.

2) I saw definite patterns in the mounting of the machines. I realized that with as few as four or five baseboards, almost any machine commonly encountered could be accommodated.

Based on number 2 above, I decided it was worth it to go ahead and build the prototype workstand. And then try to figure out number 1.

Which brings us full circle to the top of this post, a second best guess in fine tuning the balance of the swing frame.

And for perspective, these balancing matters are minor. Even what I would call "out of balance" can usually be rotated with one finger. Just pushing a little harder.

More on the new workstand soon.

John

K-Roll

Such detailed work & method, and very clear explanations. I feel smarter just reading it. A gift to us all. I like the way you decided on the balance board and testing the balancing.

Farmhousesewer

John,

Thanks for continuing to educate us through your work method and progress.

OurWorkbench

A NEW LOCK DISC

What I thought would take a couple of days turned out to take much more. I decided that I would try to use the most precise method of drilling and cutting the discs, the method of using a drill press and a drill jig with a centering peg, detailed earlier in this thread at:
http://www.quiltingboard.com/vintage...ml#post7259359

The thing that took the time was an effort to improve on the method of cutting the circular disc. I made three separate guides for use with my bench-top bandsaw, the final two of which are shown here. The first went in the trash. The bandsaw simply would not follow the circular path I wanted it to. I'm sad to say I spent a few days experimenting with this.

(Bandsaw Edge Cutting Guides)
[ATTACH=CONFIG]549947[/ATTACH]

I finally gave up and cut the disc with my hand jigsaw. This is the same way I cut the lock disc for the original prototype workstand. This actually turns out to be easier and simpler. I can get a very good circle. The results are shown below.

(Disc Cut With Jigsaw)
[ATTACH=CONFIG]549948[/ATTACH]


Drilling

I want the sixteen holes to be equidistant from the center hole, which is the center of rotation. Uniform drilling allows the lock pin to work equally well with all holes. I printed out the lock disc template located earlier in this thread at:
http://www.quiltingboard.com/vintage...ml#post7252380

I considered several ways to get the sixteen radial marks transferred to the wooden disc. I finally decided that the easiest way was to punch the centers with a hole punch. There are already horizontal and vertical lines on the disc from the process of cutting it. I aligned the paper with the pencil marks on the wooden disc at 3, 6, 9 and 12 o'clock, then marked through the hole locations in between. These marks will show me where to position the disk as I drill each hole. The smaller disc is incidental and goes on the opposite side of the workstand for equal spacing of both pivot shaft assemblies.

(Lock Disc Printout)
[ATTACH=CONFIG]549949[/ATTACH]

I made a jig from a block of wood, with a peg for the disc to turn on. The block is clamped at the back to the bed of the drill press and cannot move. The loose piece of scrap wood under the drill bit can be moved around to offer a fresh spot to drill into, for each successive hole. Drilling into a piece of wood underneath minimizes back side splintering around the hole. The basic setup (without disc) is shown below.

(Drill Press Setup)
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The disc is placed over the peg, ready for drilling.

(Disc Ready For Drilling)
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I stopped part way around the disc to take this picture.

(Disc With Holes Drilled)
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The completed disc is shown below. It has been drilled and pegged with a pin to lock the disc to the perforated tubing upright. The peg is new. I believe it is an improvement over the previous lock disc design.

(Completed Disc)
[ATTACH=CONFIG]549953[/ATTACH]

The lock disc is made from birch, which is not a particularly good match to the redwood. I'm thinking I'll paint it white, along with the smaller disc, to match the white swing frame. I'll post pictures after painting.

More soon,

John

OurWorkbench

Question On Sewing Machine Bed Sizes (longwinded)

Over the last few months I have been refining the original workstand, building another in an effort to perfect each aspect of it. The first prototype workstand was simply a home-brew project, mostly done as a proof of concept. Had it not been for other peoples' interest, I would have been quite content with the first one, which works quite well.

In recent posts I have detailed the making of a better swing frame, using a more elaborate jig to hold the pieces together. In the process, I made an adjustment to the pivot point. I made a new base, to experiment a little with the color design of the workstand, using a natural finish on the redwood material. Most recently I detailed a method of making a more perfect lock disc mechanism.

This brings me to the final aspect of the new workstand, the baseboards. I have a question for the many expert people here and to those who have large collections.

It is a difficult question to even formulate and needs some background.

Setting Up The Question

The baseboard which we use the most is what we call the Singer Universal baseboard. Somewhere around the early 1900s (others here would know better), Singer began using a standard cutout for their treadle domestic sewing machines, which I have chosen to call "classic method of mounting". Becoming a widespread standard, sizes and shapes might vary between manufacturers, but for more than half a century the mounting method for domestic sewing machines was fundamentally the same. This uniform method of mounting is what makes this sewing machine workstand practical. A diagram of this type of mounting cutout is located above on this page

Over the years, Singer made machines with this same bed size and shape, allowing machines to be interchanged in a treadle base. Somewhat surprisingly, many other manufacturers adopted the identical mounting, allowing even non-Singer machines to be interchanged. As a result of this standardization, some people enjoy putting a motorized machine in an older treadle base, even today.

One might speculate that a time came when sewing machine manufacturers believed that the treadle was obsolete. They may have thought, "Who would want to pump a sewing machine with their feet when motors are now available?"

With the apparent assumption that treadle belts were a thing of the past, manufacturers made some machines that were an additional two inches in bed length. They adopted the two inch treadle belt area to add to the bed. The pillar was usually larger and frequently contained the motor. This made for a cleaner design, without the outboard motor in the back. An example of what I am calling an oversize machine (using the Singer Universal baseboard) would be a Necchi Supernova, although I've seen many others, including newer Singers.

Therefore, I have made the Singer Universal baseboard cutout 16-5/8 inches to accommodate either standard or over-size machines.

Question

Apart from the Singer standard size, were other sewing machines made that were widened to include the treadle belt space?

1) Singer three-quarter size and Pfaff K (maybe others) use the same type of cutout, but smaller
2) Many older Whites use a similar cutout, with a slightly different size and more rounded corners
3) Kenmore, which mounts the same way, is different in dimension and has more squared corners.

I believe all of these were treadled at one time. But I have never seen an example of a later produced machine that was over-sized. I'm thinking that this was done ONLY in the most common Singer standard bed size. Is that right?

If I'm correct in my observations, I won't need to add the two-inch treadle belt space to the other baseboards (1, 2 and 3 above). Anyone's thoughts or advice would be appreciated.

Thanks,

John

Jane Quilter

Awesome, you are very clever.

Cari-in-Oly

The only thing I can think of right now is that there are a few Japanese made Kenmores that have the same footprint as Singer/most Japanese machines and that the square cornered Kenmores also have different hinge spacing than the others. AFAIK, I don't own any machines that wouldn't fit the standard base(other than my free arms or toys) so I'm of no help to you there.

Cari

sewbeadit

Thanks for the info, and I don't have a clue on that question. I think the standard one you are doing will be what I would need the most.

OurWorkbench

The last few days I've worked on several aspects of the second workstand being built here. I have the new lock discs done. I used a more elaborate and precise method of drilling than I did the first time.


Lock Discs

This is a picture of the setup I used, after the band-saw didn't work, to make a plywood circle. I cut several plywood discs with my hand jigsaw, figuring the sander might take a few tries, which it did. Following this with the disc sander makes a pretty good circular edge for the outside of the wooden disc.

The sanding disc is facing the camera. A strip was clamped to the bed of the disc sander. The block with a peg holds the disc. The block can be slid sideways into the sander, as the wooden disc is turned. This sands off the slight excess material, that I purposely left when I cut it with the hand jigsaw.

(Disc Sander)
[ATTACH=CONFIG]551258[/ATTACH]

Shown below, is the second lock disc and the smaller disc used for symmetry on the other side.

(New Lock Disc)
[ATTACH=CONFIG]551259[/ATTACH]


Numbering Both The Frames

I decided on a way to number our swing frames, since the second frame looks pretty much like the first. With numbers, we can easily tell them apart. The second frame has improvements.

I ground the angle iron down to bare shiny metal in a small area for the number. Angle iron has a dark gray to black finish. In the shiny area, I numbered it with a marking pen, followed by spraying a clear coating over it. When the clear coat was dry, I masked it off with a little piece of tape and then painted the frame. Removing the tape, the bordered frame number shows through.

(Frame Number)
[ATTACH=CONFIG]551260[/ATTACH]


Lock Pin

I've been thinking about something a little better for the lock pin. I thought I'd try an idea on a scrap of redwood. I still haven't drilled the lock pin hole on the new redwood base. I want to experiment a little before I do.

I've had in my head the idea of a white recessed cutout, that would make the pin more flush with the surface when normally locked. I'm thinking of some kind of visual indication when the pin is not locking the frame securely.

(Lock Pin Test A)
[ATTACH=CONFIG]551261[/ATTACH]

Janey and I stopped by Sheila's, a local beauty supply store, where I bought the brightest color of fingernail polish I could find. Probably went overboard. Luckily, they make fingernail polish remover if I decide to tone it down. But this demonstrates the general idea.

(Lock Pin Test B)
[ATTACH=CONFIG]551262[/ATTACH]

I'd like the lock pin to be a little more finished than on the first workstand. The first workstand base, I just drilled a hole and used an old ball-cap hinge pin. It really needs some kind of improvement.

While I like the way this recesses the lock pin, I have concerns with the loss of thickness in the wooden upright, which needs to hold the pin securely. Being about half an inch in depth, the recessed hole reduces the thickness of the wooden upright that steadies the pin.

I'm considering some other ideas before I commit to this final step, actually installing the lock pin on the new redwood base. Maybe some more tests on scraps.

More soon,

John

K-Roll

I can't add anything but "wow". What thoughtfulness and precision.