Traversing guide

Topics related to wrapped rotary machining in Aspire or VCarve Pro

Traversing guide

Postby RoutnAbout » Tue Sep 09, 2014 3:09 am

I'm needing some direction on how to duplicate this traversing guide.
After I get the vectors wrapped correctly, I think I can adjust to them for the proper take up spool.
Approximate dimensions (of the traversing guide in the images) are 7in long and 3.5in diameter.
Don't know the depth of the groove either but can experiment once I get this thing wrapped.
I don't think the images are 180 degrees to each other but close.
Notice that the guide grooves don't intersect each other, but will allow the string to cross and catch on the groove once it's crossed the opposite directional guide groove.

Thanks in advance
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screencap_1.jpg
screencap_2.jpg
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Re: Traversing guide

Postby jseiler » Tue Sep 09, 2014 4:41 am

cover it with silicone mold compound (many choices from smooth-on). Slice down the side and remove to flatten it out. Now you have something you can 3d scan, flatbed scan, measure easily. Just a thought.

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Re: Traversing guide

Postby RoutnAbout » Tue Sep 09, 2014 8:25 am

Thanks John,
Great Idea,, the problem is, all I've got to go by are the two images.
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Re: Traversing guide

Postby glenninvb » Tue Sep 09, 2014 12:45 pm

Don,

Brings back memories of commercial fishing.
Looks like a basic level-wind or diamond screw, w/the exception of the discontinued thread cut. there should be drawings for diamond screw geometry on web. Are you trying to replace an existing part or.... would a conventional level-wind work? If you know the mfg. of photo part? they may have a drawing? Just looks like a diamond screw but the thread root shallows before intersections,


http://rempco.com/level-wind-pawl-assemblies/
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Re: Traversing guide

Postby glenninvb » Tue Sep 09, 2014 1:47 pm

I'm guessing that levelwind screw is driven in a large reduction ratio by the take-up spool? or some other means?
If that's what it is?
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Re: Traversing guide

Postby RoutnAbout » Wed Sep 10, 2014 2:44 am

glenninvb wrote:Brings back memories of commercial fishing.
http://rempco.com/level-wind-pawl-assemblies/

Hi Glenn,
Don't think it has anything to do with commercial fishing. While looking for information on this, it appears it's widely used in the string and wool industry, and I think the part was made in India. From the looks of it, it'd be around 90 bucks and another 40 to 60 from shipping. Don't think I'll purchase just to recreate it....
The client is set on using a traversing drum like this.
Guess I'll dig out the old manual drafting books to see if I can undeveloped\unwrap the guide vectors.
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Re: Traversing guide

Postby glenninvb » Wed Sep 10, 2014 3:16 am

Yeah,
I know your part wasn't related to fishing, just reminded me of the longline levelwinds I had to repair at times, figured yours was some textile part or wrapping machine.
Looks like it might be made from Delrin? if plastic?
Sorry I can't help with the toolpath as don't have 4th axis and never played with a wrap gadget.
But I would guess it would be done like a long pitch screw or actually 2 (left and right hand) with a segmented fluting toolpath :?:
The math is beyond my abilities also :(

Anyway, it was interesting and I was bored, but would love to see the end results
Please post and with a snip of toolpath if possible

Thanks
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Re: Traversing guide

Postby PaulRowntree » Wed Sep 10, 2014 4:18 am

I think this is one way to start. The 4 ends of the vectors near the corners are slightly curved to make a smoother transition when changing direction. This is toolpathed with a V-groove, but as has been said, when you figure out which cuts taper out, you can just make the cuts using the fluting toolpath. The circles on the vector diagram let you use the scissors to remove short bits leading to the crossing.

The crossing seen in the wrapped view is the top edge of the job meeting the bottom edge. There is another crossing on the opposite side of the cylinder that is the point where the vectors cross.
Attachments
Diamond Screw 1.jpg
Diamond Screw Vectors.jpg
Diamond Screw v1.crv
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Re: Traversing guide

Postby PaulRowntree » Wed Sep 10, 2014 4:59 am

Here is a first try with non-overlapping spirals. Definitely the wrong cross-over pattern, but you can see where this is going ... The vectors are cut 0.1" from the crossing, and the grooves are 0.1" deep.
Attachments
Diamond Screw 2.jpg
Diamond Screw Vectors 2.jpg
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Re: Traversing guide

Postby glenninvb » Wed Sep 10, 2014 2:15 pm

Who needs math and machinist handbooks when you've got intelligent software, and guys like PaulRowntree :D

I actually drew the basic concept (with the slightly rounded corners) using flute (ramp at start and end) and previewed (2d), didn't post though because I didn't want to embarrass myself more than normal :oops:

:idea:
You could scale the photo and measure if the exact pitch is important.

Most diamond screws are pitched or turned at a speed that best lays line, wire, rope etc. according to the material diameter. On ones I'm familiar the screw length (machined thread)and take-up spool width should match for proper laying. At least that's my experience, "your application may be totally different".
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