Measuring thread thickness objectively using serving rope machine

[modeller_masa]

Hello,

I've read some posts regarding thickness of thread and ropes, and found that thickness of thread is variable number in multiple circumstances. Most posts recommend to make a personal subjective chart, so I made a thickness measurement system using Domanoff's SM4 serving rope machine.

 

 

This is my current setting of SM4 serving rope machine. Sub-thread's tension is controlled by LEGO weight, so I don't touch neither tension stress nor width of revolutions. It makes much better and consistent result.

 

 

Only thing I need to measure thickness of thread is 3.00mm wood rod.

 

 

I've tested some of my favorite threads. This is my best cotton thread ever seen. The DMC cordonnet special or dentelles series are cotton with almost zero pills, and used as lace thread or tatting. I'm newbie, so it is difficult to remove dirty pills of ordinary cotton or poly threads.

 

 

This is an 'ordinary' cotton thread. The DMC pearl cotton 5, 8, 12 has tons of dirty pills, and its spin is so loose. wefalck said that most conventional threads for clothes are not suitable for model work, and ropewalk is mandatory to get tight rope.

 

I'm planning to unravel cotton threads and rewind them using automated ropewalk - Domanoff PL4-4 which I'll receive this week. 

 

 

Amann's serafil fine thread is one of the finest thread. This is polyester filament thread. It has zero pills, so sometimes it looks like a plastic. You may be familiar with Gutterman's Mara series, but in South Korea, Amann is dominant brand in this segment. Gutterman is the best company in global market, and has more variable colors. Amann is second biggest company in Germany and has less color, but Amann has thinner threads. While Gutterman's Mara 220 is TEX no.13, this serafil 300(200/2s) is TEX no.10. Also, you can buy more thinner serafil 420(300/2s) which has TEX no.7. Moreover, if you unravel the serafil 420, you'll get TEX no.5 mono filament which has 240 colors with economic price. (TEX no.5 = 50 Denier)

 

https://www.servicethread.com/tools

(Thread conversion calculator)

 

 

Some threads are hard to notify each revolutions, so I used flatbed scanner. 

 

 

Much better and easy to calculate revolutions.

 

 

It is DMC pearl cotton No.8. Its WPI (wraps per inch) is 46. It can be converted to millimeters - 0.552mm (= 25.4mm/WPI) It is still subjective number and can be changed in different situation, but it is important to make personal references to compare various threads.

 

 

DMC Cordonnet special 20 (Blanc color) : 56 revolutions

 

 

DMC Cordonnet special 100 (Ecru color) : 83 revolutions

 

 

Amann Serafil fine 300(200/2) (1382 Black pepper color) : 175 revolutions

 

 

Final result. I'll update my personal reference chart as I buy new threads.

 

I'm using rope serving machine to get consistent result in the future. I hope we make better objective way to share thread specs each other.

Edited March 3, 2021 by modeller_masa

[popeye2sea]

Nice method. But it strikes me as a bit overkill.  Why wrap more than one inch?  Count the turns in one inch and then do the simple division. For very thin diameters you can even wrap a fraction of an inch, like a 1/2 or 1/4 and then do the appropriate math.

 

Regards,

[modeller_masa]

Hello Henry. It is not difficult to wrap one more inch with SM4 + motor option because it takes only 2~3 seconds. Also, I used flatbed scanner with ruler to measure an inch length as you see. The grey and orange blocks are inch length paper ruler I'm using. I need 2~3 inch to measure it. In addition, I used Epson V37 CCD flatbed scanner which scans up to 4800 DPI. It is not hard to count each revolutions of the serafil 300 super fine thread with 4800 DPI resolution. I would say TEX no.5 thread also won't be a problem, and such high resolution and enough error margin gives 'overkill' objective accuracy as valuable information we can share.

 

There may be more efficient and simple way we can share WPI numbers. (I think WPI or WPC is the best way to measure thickness of thread used in wood model ship.)

[popeye2sea]

Your method is good and sound. It does allow you to average out any inconsistencies in the wrapping.

 

Regards,

[wefalck]

Well, I used to run 20 turns around the shaft of a drill, not too tight, not too loose and then measured the distance. Divided by 20 gives you the thread diametre.

 

We had the discussion recently in another thread: using the bulk density of the material, say polyester, the den or tex and a bit of geometry, one can also calculate the diameter. For instance, vor Veevus 16/0 fly-tying thread, which has 50 den, I calculated 0.04 mm and a colleague here measured 0.038 mm - so a pretty good match.

Edited March 4, 2021 by wefalck

[modeller_masa]

Thanks, Henry. I would say that this overkilling method is good for newbies or babies because of easy of use.

 

I've never imagined the super simple idea that using drill. 😖 It may need some trial and errors, but it costs almost zero to compare with my method. (about $200.)

 

0.038mm is thinner size than I calculated. Also, I found that the serafil fine 420 series has only two colour options - black and white. Both of them cost a lot, so I'll open my subjective chart when there are more than 100 lists. (not in near future) Thanks for interesting information, wefalck.