Friday, January 23, 2015

RPM update

The new geometry is faster, and it took me months to learn to use it.  Net drive ratio is on the order of just over 58. so with my normal treadle cadence of 90, I should get just over 5200 rpm of spin insertion. I have not even come close.

Drive band(s) slip was on the order of 20%, meaning actual twist insertion was only about 4,200 rpm.

However, 4200 was as fast as I could spin for months.  Now, I am more comfortable with that kind of speed.

Thus, last night, some more tension on the drive bands, (using a pair of 8 oz weights with a spring between them), and this morning twist insertion is up around 4,800 rpm.

For 9 tpi worsted, that is ~14 yards per minute, which is faster than I can pull fiber off the distaff, so I am working on a new distaff design and geometry.

On the other hand it will do 17 tpi shirting singles at ~ 8 yards per minute, which is a nice pace.

When I first sat down at the Traddy some years ago, it felt like a race car that wanted to go faster. Now, it feels like a race car that is running near its design speed. It is like an old Ferrari,  tuned by the factory race team, running time trials at Sebring.  It is going almost as fast as it can go.

Spinning oil
(applied frequently)

Commercial cap  and later ring spinning frames ran at about 5,000 rpm.  My best guess is that 5,000 rpm is about the maximum speed for flyer/bobbin spinning to run on a routine and sustained basis.

Do I  think Scotch tension systems can run this fast - not likely.  Single drive, bobbin lead (Irish Tension) is mechanically more like the  cap spinning devices.  On the other hand there were hundreds and hundreds of patents for bearings and geometries before the commercial cap spinners were able to run that fast,  and then the technology was only used for a few years, before better spinning devices came along.  I think an Irish tension is a hard way to get to 5,000 rpm.  That said, I do use Irish Tension for plying with jumbo bobbins, and it runs at - 3,000 rpm using a ratio of 33:1.  Irish Tension at 3,000 rpm is easy.

A note on ergonomics.  If you do not have to spin as long to get a project done, then there is less  total stress on the body.  And, DRS hugely reduces the stress of spinning - particularly on the drafting hand, drafting hand wrist, and drafting hand forearm. I could not spin as much as I do, if my drafting hand had to resist the ongoing tension of Scotch tension.

My lazy kate has a tension box so there is essentially no stress on my hands while plying.  I just sit there and treadle, pausing every so often to move the flyer heck, and place new bobbins of singles on the lazy kate. 


Dr Gan Sei said...

I've been wondering about your plans to raise the nap and crop the bolt of shirting, sometime in the future, when you've woven it. What tools and technique are you planning to use? Have you access to cropping shears, or do you plan to forge them yourself?

Aaron said...

I intend to cheat. eg, raise the nap with a fine brass brush from the local hardware store, and clip the nap with electric hair clippers - from Walgreens.

Ruth B said...

Well,if you're going to use electric clippers, then it won't be an historically correct fabric, will it? Unless, of course, you're going to try to prove that early textile manufacturers had electric clippers. So sorry, Aaron. YOU LOSE!!!

Aaron said...

My motivation is the make fabrics that serve my needs.

When I have good fabric at a reasonable cost, I win.

E said...

How much did that loom cost? This bolt of fabric is going to turn out to be very expensive once you factor in cost of loom, mods to your Traddy, your hours of experimentation, carding, and spinning.

Aaron said...

Oh yes, the education is very expensive, but how many bolts of fine white hand spun, hand woven wool cloth do you see around? When something is that rare, what is its price?

The loom needed a good home. Who can resist an orphan? Not even the Pirates of Penzance!

Holin Kennen said...

And how many bolts of fine white handspun, handwoven cloth have you made. Exactly zero! You haven't even warped the thing yet. You've been going on and on about spinning the warp and bragging about how many thousands of yard you spin, but your results are nil. Given your actual production, which is non-existent, the Emperor will have no clothes.