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A Domanoff inspired rope making machine


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Because my pilot cutter needs longer ropes than I can make on my 10 foot long traditional ropewalk, I have been working on one inspired by the design that Alex Domanoff designed.

 

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My machine uses an "O" ring belt drive and is only 3.5 inches in diameter. it uses the bobbins from my old Cepel treadle sewing machine the bobbins seem to be a bit wider than some they are .47 inches wide.I have started testing the machine and still have to make the take up spool.

 

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The whorls are set in double 3/8 x 3/16 shouldered ball races.

 

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I am testing it with three colours so that I can sort out the tensions on each whorl. The threads are just what was already on the bobbins.

 

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The base is Brazilian Rosewood and the mounts are Gaboon Ebony.

The sun gear is phenolic 48DP 49 teeth

The idler gears are made from 48DP x15 Pinion stock

The moon gears are 48DP x 24 Duralumin gear that was 6 inches long salvaged from some equipment 30 years ago.

 

Electric motor is a surplus 9v from princess auto, mounted on a piece of 1/8 thick brass with a 1/4 steel rod set through one of the ebony mounts.

 

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The 1/4 inch hole in the guide plate will accept some silver steel dies, once I know what I'm doing.

 

Thanks again Alex for the inspiration. I had the time and materials on hand.

 

Michael

 

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Some good news and some not so good news.

 

First the good news

 

I made some springs by winding some spring wire around some 3/16 rod. I used the lathe and clamped the wire next to the rod then ran the lathe in back gear and with the wire slipping through my welding gloved fingers spooled it up onto the rod .After the tension was released the wire wound open to a 5/16  diameter spring.

 

I cut three springs and then parted off some spacer washers to create different tensions on the bobbins.

 

I replaced the bobbin shafts with three longer ones that were 5/8 long. The 4/40 cap screws lock the retaining washers solid  to the shaft. the tension is changed with the spacer washers. I have .025  .035 , and .050 spacers.

 

With the .25 spacers the machine worked quite well just pulling the rope away with my fingers at this point.

 

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The rope looks a bit like old hemp rope.

 

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Now for the Not so good news.

 

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Yes about two nano seconds after the thought crossed my mind that I could easily break a tap this way.... that is precisely what happened it was a first tap through silver steel and because I was in a hurry and did the tapping with the rod in the ebony mount so I did not use any lubricant (bad choice) because of the wood below.

 

When my tears have stopped flowing tomorrow, I will use the cut off disc in a Dremel and remove the offending piece and re do it..

 

Michael

 

 

 

 

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Michael,

 

Early on I tried putting washers on with the bobbins to add drag to the lines, stopping them from freewheeling.  The Domanoff machine has felt washers on each side of the bobbins, I assume to reduce noise, but they do not impede them in any way.  I was having a problem with the thread winding on itself before it reached the guide bar and causing clumps in the rope.  Well the added drag didn't help, it only strained the take-up spool.  the remedy was to increase the take-up speed.  This was with the 'Irish' Linen, no problem with Cotton.

 

BTW,  Alexey recommends that the bobbins be freewheeling.

 

Bob W 

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Bob, Thanks for this information, i have a full day tomorrow but on Thursday I will set up the take up spool. I will have a look at the freewheeling now that I am using some quilting thread. and I will add a die into the guide bar as well.. Oh and fix the broken tap.

 

Michael

Edited by michael mott
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Christi, and Bob and Q

Thank you for your kind remarks.

Good morning Q yes the mounts are ebony, some of the stuff I have had saved for years. even after 30 years the stuff is still prone to checking a little because it was such a large log when I purchased it. 36 inches long by almost 7 inches by 4 inches as a rough hewn billet.

 

My log of English boxwood 18 inches long by 3 inches in diameter will be used for some new tooling in the not too distant future as well.

 

I have some ideas about multiple bobbins, so I will see where that leads.

 

Michael

Edited by michael mott
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Continuing on with a major design change,

 

step one was to eliminate the idler gears as not needed. This entailed using a larger central fixed gear, I found a brass 48DP x72 tooth one in the scrap gear drawer..

 

This meant that I would need some 36 tooth gears to maintain the 2:1 ratio, so I set up the mill to do that. I used a short length of Dur-aluminum turned to the correct diameter and cut the 36 teeth with the 48DP cutter for 35-54 teeth

 

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The 4 jaw chuck was then transferred to the Myford for the final machining

 

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I left a 5/8 shoulder and reamed the gears to receive 3/8 x 3/16 bore shouldered bearings.

 

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Next the bobbin holders were made from some 21/32 brass tube 1 1/2 inches long. these were filled with some birch dowel so that they could be milled without collapsing.

 

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The top ends were then opened up with a small hobby saw. then pushed onto the gears.

 

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The hole for the bobbin spindle was drilled at the same time as the side milling, this was now set up with some ball races as a filing jig to round of the ends of the arms After they had been flattened in the vice, by squeezing them over a chunk of 1/2 inch thick aluminum.

 

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A 10x32x1/2 inch long stainless cap screw is used as the holding shaft to the solar Disc to use Domanoff's  nomenclature, this screw is bored out with a number 33 drill to let the thread pass through.

 

The arms were bent to accommodate a shaft a 1/16 of an inch wider than 2 bobbins for them to spin freely on. this unit was then spun on the vertical shaft to make sure that it will revolve freely.

 

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The new solar disk will be 5 inches in diameter, with the 10x32 tapped holes for a 3 or 4 configuration.

I am contemplating wrapping some rack around the edge of the disk and using a small pinion to drive it instead of the belt.

 

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Michael

 

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Dear Michael,

looks fantastic! But you forgot why you have to use idle gears...

http://modelshipworld.com/index.php?/topic/5396-domanoff-workshop-planetary-ropewalk/#entry156085

Item 1

Because thread is not wire, it's non-deformable. You have to "unwind" each thread while they wind one around another.

 

Alexey

 

PS Using pinion to drive solar disk could increase noise dramatically...

Edited by Alexey Domanoff
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And I see you have problem with quality of "twist".

item 4 - It depends on how even strands leave spools.

My experience on this matter says - you do not need  to brake spools. I made a lot of experiments and lot of versions of spool holders... 

even in such way :-))

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and you need to give attention how thread is lay on spool.

 

 

any questions - you're welcome! you see, I sell version 2.5 and spent several years to make it...

 

 

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Alexey, again thank you for your advice and knowledge. It is great that you are selling your machines,. I have no interest is selling anything I am just enjoying building a machine for myself, and sharing what I do.

 

When you say to take care in the lay of the thread on the spool what do you mean?

 

michael

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Dear Michael,

I share my experience as well :-) And I proud if I can help  such great Master as You.

 

I mean to take care about even wound of thread on spool. If it's "soft" on one spool and "hard" on another - you definitely get "jammed" final rope.

 

Another "cure" - lower the speed of head and takeup block.

 

Alexey

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Q I like the simplicity of the gearing in the ropewalk that you illustrated, it is the way that my long horizontal walk operates. I will use it to lay up larger cables.

 

The machine has been undergoing a major rework based on my discussion with Alexey. I also watched the video that he posted on U-tube.

 

first I removed the broken tap.

 

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Next I pushed out the soldered bushings.

 

 

 

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Next I bored out the 3/8 holes to 1/2 inch on the new  pitch circle, and inserted new bushings  re-drilled for 10x32 holes and tapped them for the idler gears, and reassembled the lot. Because of the way that the thread spools are mounted the gears had to be mounted on the back side which looks better as well.

 

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Then made the take up spool motor mount from the rest of the small block of ebony that the other mounts were made from.

 

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Next the take up spools, and the guide plate which will be from some clear plex and will be circular.

 

Michael

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I have started the base which is actually going to be a small box with a drawer at the spool end. the box is 7 3/8 inches wide by 3 1/4 inches high and 16 inches long. the wood is Brazilian Rosewood I had been saving for a special project and this seemed like a good one to use it on.  I glued up the top so that the figure converged at the spool in allusion to the threads coming together to form rope.

 

The closed end is dovetailed

 

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I have now sorted the spool holder and some spools the spool is locked onto the drive with a simple pin which locates into a hole on the spool. the brass ball is salvaged from an old pinball machine I worked on years ago, mounted it onto a new shaft.

 

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The drawer will hold threads and bobbins and tools for threading and adjustments.

 

There will be two speed control pots located at the front of the machine end.

 

Michael

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