Deburring Delrin

Hey gang I'm making some parts out of delrin; they've got fins on 'em and when they're cut to length the fuzz is everywhere! I'm thinking of using m
y brass tumbler with walnut shells unless someone's got a better idea. Here 's a link to the problem: https://www.flickr.com/photos/steamboat_ed/301085 21891/in/album-72157673545442262/
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On Wed, 12 Oct 2016 12:34:02 -0700, SteamboatEd Haas wrote:

album-72157673545442262/
Ouch! I normally just use a deburring tool or pocket knife, but that'd be a pia on those. I'd guess the tumbler won't do it, but it doesn't hurt to try.
Pete Keillor
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How about filing or sanding just the ends to get the fuzz off?
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On Wednesday, October 12, 2016 at 2:40:51 PM UTC-7, Cydrome Leader wrote:

--Not so bad for one or two but I'm gearing up to make a couple thousand of 'em! :-)
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They look pretty small, even a quick twist against a sanding machine might do the trick. Spin it around and repeat. Might be a couple seconds a piece if you can find the grit that will cut that stuff off.
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On Wed, 12 Oct 2016 19:13:30 -0700 (PDT), SteamboatEd Haas

That's some serious machine time. Are you milling lengths, then cutting to width? No, judging by the burrs, you're not, are you? Which begs the Q: Why not?
Yeah, 6-up on your driveway and hit 'em with the weed burner at regular walking speed. You'll be done in no time.
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On Wed, 12 Oct 2016 12:34:02 -0700 (PDT), SteamboatEd Haas
Walnut shells might work. If they don't then tumbling with abrasive media and water will. I have deburred acetal plastics, both Delrin and Acetron, in one of my vibratory tumblers. I used trianglar and cylindrical abrasive shapes. The only problem is that the plastic will get a matt finish. For your eventual use I don't think that will really be a problem. Even walnut shells, if they can remove the burrs, will give you a matt finish. You can tumble the parts after deburring with polish but it takes a very long time, in my experience, to polish acetal plastics in a vibratory tumbler. You might want to try an abrasive filled nylon brush first to remove the majority of the burrs first. I have had good luck doing this. It is easy to melt the plastic if a light touch isn't used though. Even brass wire brushes tend to be too aggressive. Eric
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Thanks for that; matte finish not a problem; after deburring there will be a couple more operations so matte finish will be removed during that machining.
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On Wed, 12 Oct 2016 19:12:16 -0700 (PDT), SteamboatEd Haas
Damn, I spelled matt, er, matte, wrong again. If you decide to cut with a laser be aware that Delrin, an acetal plastic, will give off formaldehyde ( I spelled that right at least). Not only is formaldehyde a lung irritant and poison it also is corrosive to certain metals, most iron alloys being among them. So make sure the laser cutting operation is well vented away from people and other living things. Eric
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On Thursday, October 13, 2016 at 1:59:47 AM UTC+2, snipped-for-privacy@whidbey.com wrote:

and when they're cut to length the fuzz is everywhere! I'm thinking of usin g my brass tumbler with walnut shells unless someone's got a better idea. H ere's a link to the problem: https://www.flickr.com/photos/steamboat_ed/301 08521891/in/album-72157673545442262/

Eric, can you point me to a source for fine abrasive filled nylon brushes? I spend a lot of time cleaning 5/16-24 brass threads. I use .2mm bristle br ass brush wheels and tripoli. It works, but I'm on the lookout for somethin g better.
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On Sat, 12 Nov 2016 13:23:22 -0800 (PST), robobass

Does MSC sell to your part of the world? They sell Weiler brand nylon wheel brushes that have a filament diameter that is nominally .018 but can be as small as .010. I have used these brushes and the ends can wear to a point which is what you need to get into the root of a 24 TPI thread. Weiler does make good brushes and with that name may be made much closer to you than me here north of Seattle. Have you considered fine steel brushes? They cut fast and can be too aggressive on soft metals like annealed brass. But a light and quick touch could result in a roughing op. that leaves the surface perfect for a fast tripoli treatment. You could try a jewellry supply company for the brush but they tend to carry ones that are too small. I have had the occasion more than once to polish small brass threaded parts and found that E5 emery on the right buff will cut fast, get to the root of the thread, and leave a finish that is usually already good enough and if not then either tripoli are rouge can be used. For REALLY nice color on brass I like Fabuluster. But that's probably more work than you need to do if you are stopping at the Tripoli stage. BTW, did any of the sprayer suggestions here pan out? Eric
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On Saturday, November 12, 2016 at 11:25:44 PM UTC+1, snipped-for-privacy@whidbey.com wrot e:

te:

em and when they're cut to length the fuzz is everywhere! I'm thinking of u sing my brass tumbler with walnut shells unless someone's got a better idea . Here's a link to the problem: https://www.flickr.com/photos/steamboat_ed/ 30108521891/in/album-72157673545442262/

s? I spend a lot of time cleaning 5/16-24 brass threads. I use .2mm bristle brass brush wheels and tripoli. It works, but I'm on the lookout for somet hing better.

Eric, I did try a .010 nylon bristle brush from McMaster but it didn't do anythin g. Here is a photo of what I'm doing:
http://i389.photobucket.com/albums/oo340/robobass/threads_zpsxgwuln1x.jpg Now I am applying something called Stop Ox II with an airbrush, which minim izes waste quite effectively. Upper right is the typical result after a vin egar pickle in a ultrasound bath. Lower right is when something went wrong and I had to torch the part for way too long. Upper left is after using a . 008 brass brush with tripoli, and lower left is after finishing with a clot h wheel and fine compound. I was happiest when running a drill press mounte d 3" wheel at 2350rpm, but I simply can't get those wheels anymore. The sup pliers will insist that they are brass, but they are all plated steel these days. I have a 10" brass wheel that I run on the lathe at 1100rpm, which i s maybe too fast. I get good fast cleaning, but a bit too much scratching, and I can't just drop it in the ultrasound bath to clean it. Overall I'm in pretty good shape, but I'd still like to find a bristle wheel for the fine polishing stage. McMaster has Tampico brushes which look good, but I wonde r how long they will last, as they aren't exactly cheap.
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On Tue, 15 Nov 2016 01:10:57 -0800 (PST), robobass

Cool!
P.S: I'm sending that link to the Neutrino Bass Cable to a musician friend. He's a rhythm guitarist but sits in on regular bass guitar on occasion. I think he'll get even more of a kick out of it, as he's retired from the NRL in D.C. Y'know, I'll bet those sound even better than those Oxygen Free Copper cables everyone is (was?) selling. <g>

That's a lot of process work, but brass sure is pretty when it's finely polished like that. I think it's my favorite metal. Your finished product is beautiful. Is that a high-shore rubber sleeve? Or maybe thick PVC?

Y'think? That's 51.6% faster than your ideal. Why didn't you slow down the lathe? Or did that speed work best with the density of the larger diameter brush?

It seems like almost all brush prices have skyrocketed lately. I tend to use bronze brushes (toothbrush size) for cleaning gunk out of threads. They tend to hold up considerably longer than brass. The cheapies bend half their bristles on the first pass, and the good ones have tripled in price over the last decade.
I have no experience with tampico wheel brushes, so I don't have anything to offer there.
I was wondering how you hold those parts while cleaning. I hate getting my fingers in the way of the high-speed bristles for some reason, so I think I'd run weld the ends of a strip of sheetmetal to opposite flats of a 3/8-24 nut, run it through the bandsaw to halve it, clean up the cut threads, and run a piece of hose over the handle to hold the halves together. I could 'clamp' it on the brazed end to clean up the free end, then rotate it through the revolutions to get all the threads cleaned. I first thought of using a long standoff, but that wouldn't hold it for the free end threads.
Just thought I'd share that.
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On Tuesday, November 15, 2016 at 3:29:49 PM UTC+1, Larry Jaques wrote:

rote:

wrote:

n 'em and when they're cut to length the fuzz is everywhere! I'm thinking o f using my brass tumbler with walnut shells unless someone's got a better i dea. Here's a link to the problem: https://www.flickr.com/photos/steamboat_ ed/30108521891/in/album-72157673545442262/

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shes? I spend a lot of time cleaning 5/16-24 brass threads. I use .2mm bris tle brass brush wheels and tripoli. It works, but I'm on the lookout for so mething better.

hing. Here is a photo of what I'm doing:

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nimizes waste quite effectively.

bath. Lower right is when something went wrong and I had to torch the part for way too long. Upper left is after using a .008 brass brush with tripol i, and lower left is after finishing with a cloth wheel and fine compound.

ut I simply can't get those wheels anymore. The suppliers will insist that they are brass, but they are all plated steel these days. I have a 10" bras s wheel that I run on the lathe at 1100rpm, which is maybe too fast.

t drop it in the ultrasound bath to clean it. Overall I'm in pretty good sh ape, but I'd still like to find a bristle wheel for the fine polishing stag e. McMaster has Tampico brushes which look good, but I wonder how long they will last, as they aren't exactly cheap.

Larry, I hope your friend wants a cable, cause sales have been dismal. I have no i dea why.
I do realize that I'm running the big brush way faster when looking at surf ace speed. I do need to experiment with this further. The brush should outl ast many dozens of small brushes. I found it surplus.
I don't have an issue with holding the parts. I spend so much of my day hol ding these things to the various abrasive wheels that it is second nature. When I do on rare occasion touch knuckles with the man, I just step back an d remind myself that I need to keep focus. That said, if you looked at my h ands, your first guess at my profession would not be concert pianist. Ironi c, since for most of my life I was an orchestral double bassist.
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On Tue, 15 Nov 2016 07:06:12 -0800 (PST), robobass

He'll probably want two. They're small.

If you're arbored in the lathe, isn't that an easy solution?

What? You played one with each hand? Double prehensile groinage, too, I suppose?
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On Tuesday, November 15, 2016 at 11:24:04 PM UTC+1, Larry Jaques wrote:

m wrote:

om wrote:

s on 'em and when they're cut to length the fuzz is everywhere! I'm thinkin g of using my brass tumbler with walnut shells unless someone's got a bette r idea. Here's a link to the problem: https://www.flickr.com/photos/steambo at_ed/30108521891/in/album-72157673545442262/

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minimizes waste quite effectively.

und bath. Lower right is when something went wrong and I had to torch the p art for way too long. Upper left is after using a .008 brass brush with tri poli, and lower left is after finishing with a cloth wheel and fine compoun d.

, but I simply can't get those wheels anymore. The suppliers will insist th at they are brass, but they are all plated steel these days. I have a 10" b rass wheel that I run on the lathe at 1100rpm, which is maybe too fast.

just drop it in the ultrasound bath to clean it. Overall I'm in pretty good shape, but I'd still like to find a bristle wheel for the fine polishing s tage. McMaster has Tampico brushes which look good, but I wonder how long t hey will last, as they aren't exactly cheap.

o idea why.

urface speed. I do need to experiment with this further. The brush should o utlast many dozens of small brushes. I found it surplus.

holding these things to the various abrasive wheels that it is second natur e. When I do on rare occasion touch knuckles with the man, I just step back and remind myself that I need to keep focus. That said, if you looked at m y hands, your first guess at my profession would not be concert pianist. Ir onic, since for most of my life I was an orchestral double bassist.

Jawohl, Herr Jaques! I slowed down the lathe to 550 for the 10" wheel, and everything works perfectly now. This wheel should last for years, so I will stop fretting about finding 3" wheels that are real brass. As to my musica l instrument, it is called the Double Bass because it plays an octave lower than written, doubling the cello line in octaves in the classical literatu re. You may know it better by colloquial terms such as "stand up bass", "do ghouse bass", or simply "bass". Playing one in an orchestra is a wonderful way to make a living, but unfortunately, a living is only to be had by thos e who play it wonderfully. I had a good run, but didn't make it to the top rung of the ladder. At least my time is my own now, and I have time play wi th my kids!
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On Wed, 16 Nov 2016 04:08:57 -0800 (PST), robobass

Great. Glad I could help. It's amazing the simple things we can overlook, or perhaps, are too lazy/hesitant at the moment to change things.

Yes, I always heard of them in jazz bands as "stand up bass". I love 'em. Music you can really feel in your bones, even if you're not the one playing them.

My friend, Rob, is now retired and in a theater orchestra, playing background for really corny (IMHO) plays. But he's happy, even though they don't pay well.

My time is my own now, too, and I can't believe how busy I am. It seems I have time to do all those little projects I put off for 40 years, and I want 'em all _now_!
Instant Gratification Takes Too Long.
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I don't know why I didn't try to match the surface speed when I got the big wheel. I guess 550 just seemed so slow!
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On Wed, 16 Nov 2016 06:49:58 -0800 (PST), robobass

I was going to mention that, but you said "everything works perfectly now" so I let it alone. 705rpm is your ideal speed, unless the density of the brush changes that.
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On Wednesday, November 16, 2016 at 7:24:41 PM UTC+1, Larry Jaques wrote:

ow

the

, and everything works perfectly now. This wheel should last for years, so I will stop fretting about finding 3" wheels that are real brass.

big wheel. I guess 550 just seemed so slow!

Thanks for the calculation. I did it at one point, but have lost the data. With the belts on my lathe, it is quick to change between 550, 1100, and 22 00, but a bit more involved to get other speeds. Yes, 550rpm works well for initial cleaning with tripoli. I think I will try a Tampico brush for the final finishing, as that is still a bit laborious. I use a super fine compo und that is not rouge, and I use heavy sewing thread to clean it out of the machine threads. Yes, this is a process intensive operation, but my niche market seems to appreciate the effort. I'm still in business, anyway!
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