Metal Finishing Questions

Question 1:
Is there any way to remove scratches from a ground surface finish (the surface is flat) and have it match the existing ground finish without
regrinding the entire surface?
Question 2:
What media compound(s)works best in a tumbler to put a high shine on steel parts that have rusted and been treated with phosphoric acid (all rust removed, part now has a blackened dull finish)?
Jon Banquer San Diego, CA
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On Sat, 9 May 2009 16:17:58 -0700 (PDT), jon_banquer

If the pitting isn't too deep try walnut shells and maybe add a light polishing compound, rouge or tripoli. Would prefer to use vibratory bowl but tumbler may work.
If pitting is deep it may be best to use a medium to rough abrasive to cut through the pitting and create an even (rough) finish all around, then change to a mild abrasive and for the final load walnut shells possibly with a polishing compound to bring it to a "high shine".
-- Tom http://tinyurl.com/5okkgz
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Depends on your flatness callout.

Don't know.
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Lets start with wide open and it's just cosmetic.
Jon Banquer San Diego, CA
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jon_banquer wrote:

    ScotchBrite pads and a DA orbital sander. That will give a crosshatched pattern. Start course and finish fine. After the deep scratches are out finish in your tumbler or tape some sandpaper down to your surface plate and do like Vinny suggested.
--
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They are small parts that won't really fit or take to a DA or random orbital sander.

Question 1 and Question 2 weren't related and that is why I made them two separate questions. I guess I could have gone the extra step and tried to be even clearer and said Question 1 and Question 2 weren't related.
The parts in Question 1 won't work on a DA or random orbital sander and don't have deep scratches... they were rusted, I treated them with phosphoric acid and they are now dull and black. The part in Question 2 would take a DA or random orbital and does have deep scratches.
I'm going to try what Vinny said, as he seems to have plenty of real world mold making experience with this problem.
I'm sorry you once again confused beyond belief (to me) what I posted as you often do. Inspire of this I often get useful information from what you post (talon grips, etc.) so I wouldnt want to discourage you from posting helpful information that I can use despite the FACT that you often get most of what I post very badly wrong and others get it right. I no longer have the interest in correcting the mountain of misinformation you post and haven't for some time.
Jon Banquer San Diego, CA
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jon_banquer wrote:

Jon:          I was just giving some options to remove scratches. We did it all the time. If my suggestions help - then great. If they're not usable for whatever reason for your current project - then just file them away in your memory banks for possible future use.
    You can always get a cheapie Harbor Freight glass beader to clean rust and discoloration off parts.     If sometimes my answers are a little too far "out of the box" for you, then just ignore them. They are just suggestions, not mandates.
--
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Bob, I hope you are starting to catch on that he is Only trolling for an argument. According to one source, 1 out of 25 people are totally devoid of any concience. They are sociopaths, and cannot be reached through their "concience" since they have none, and cannot comprehend the concept of one, either. Jon has never demonstrated any empathy for another human being.
I do apploud your unending attempts to reach him, but I don't beleive it will work.
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Half-Nutz wrote:

HN:
    You know, I think you may be right. With his recent spate of comments (measuring to 1/2 a millionth), and apprentice questions (how to get scratches out of parts - what's the different between round and square boring heads - or why you'd have to measure a rigid angle chamfer tool at more than one dept rather than trig. it out - or not knowing that thread gauges can be sent out to be checked & calibrated - etc. etc.) - these are all questions that should have been answered in the first year of machining.     Soooo it appears that the questions are just trolls like you suggest, or someone seriously hasn't been paying attention for the decade and a half they've been in a shop(s).
--
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The vibratory tumbler being used is a Model UV-10 Industrial (Stk #183 IND)
http://www.thumlerstumbler.com/industrial.html
Jon Banquer San Diego, CA
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On Sat, 9 May 2009 19:36:02 -0700 (PDT), jon_banquer

Well you did say "tumbler" which usually refers to rotary barrel tumbler. http://www.mcmaster.com/#about-barrel-tumblers/=1t3shj NOW! that you added "Vibratory"
If the pitting isn't too deep try walnut shells and maybe add a light polishing compound, rouge or tripoli.
If pitting is deep it may be best to start with a medium to rough abrasive to cut through the pitting and create an even (rough) finish all around, then change to a mild abrasive and for the final load walnut shells possibly with a polishing compound to bring it to your required "high shine".
---------------- FYI:
Centrifugal Barrel is a great way to go, amazing machines. We used it and got near mirror finishes on machined parts as well as raw castings and forgings.
http://www.mikro1.com/equipment/tipton_hs.pdf
Tom
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Get a sheet of sand paper and put it on a surface plate and rub the part on it the direction of the grinder marks. Rip off a corner of the paper and rub the spot across the scratch a few times the direction of the grinding marks. Then rub the whole part on the flat piece of sand paper on the surface plate the same direction again. Go back and forth until its hidden. Start with 600 paper, and change to a coarser or finer sheet as needed to match the grind. Just takes a minute to hide deep scratches on a fine grind. If it's a soft steel or aluminum, take it slow and easy. If its hardened, give it hell. When I repair a mold, I do that to all the parts real quick, turning it into a brand new mold. Some say it's cheating, but I feel it's part of the grinding process. Plus it makes the surface less prone to scratching. Sometimes it's best to use a "used" piece of sandpaper. Just make sure you wipe off the back of the sandpaper on your pant leg before putting it on the surface plate, a small piece of dirt will cause a new scratch.
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Vinny's got it. Thats they way to it. Being a moldmaker for a few years you basicaly have to learn how to "hide" surface imperfections, ususlaly caused by handling the blocks/ sliding plates ect. before the mold is shipped to the customer. Its the last little step that gives your mold that "wow" by the customer when they inspect it. By looking closely & determining the direction of the original surface grind , sanding in that direction will easily hide scratches & shallow imperfections. To put it another way, you are scratching up the surface with fine emery paper making a new consistent surface finish emulating a surface ground finish. The only thing I have to add to polisher Vinny's :-) technique, is use mineral spirits as a lubricant. It will help "float" the particles away & keep the emery cutting & not loading up. Next step: surface preparation for class A #1 lens finish diamond polish<g> man I'm glad I'm not a polisher. Too many vibrations with the hand reciprocater (j-off machine) Those ultrasonic units are sweeeeeeeeet.
===================================================== ______ /_____/\ Best Regards, /____ \\ \ Gil Pawl /_____\ \\ / HOLDZEM /_____/ \/ / / /_____/ / \//\ West Chicago, IL \_____\//\ / / USA \_____/ / /\ / \_____/ \\ \ \_____\ \\ \_____\/ ======================================================
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On May 10, 3:36 am, snipped-for-privacy@cin.net wrote:

Very helpful background information as well as the logic to dealing with this problem.

I prefer jet fuel... kerosene. Is there a reason I have to use mineral spirits?

If you wish to describe this specific process in detail such as how many times you have to change grits of diamond polish, exactly what kind of tool is used (I have an Engis (sp?) catalog around somewhere) I'll read your post with the care that I read this one.
It's unfortunate in your push of Cimatron that you won't provide the kind of specifics and attention to detail (for drilling holes) that you have shown you can provide in this post. You criticize Cimatron horrible marketing (rightly so) but yet you are guilty of exactly the same kind of thing when it comes to describing Cimatron. There are still a few people left in this world that are interested in the important specifics rather than broad sweeping generalities such as are most often posted about Siemens NX by Bill Triffet. There is something very seriously wrong when I learn more on 3 minutes of a sales presentation of NX than I have from many, many years of reading posts on UG / NX from Bill Triffet.
Jon Banquer San Diego, CA
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Specifics are very time consuming & much thought is required to get your point across. Short if me actually doing it whilst filiming a video is about my way to explain something. Thats just me. Not much on sit'n at the keyboard hunting & pecking & allot of backspacing. (Another nice Cimatron feature- very little keyboard input besides entering numeric values - good ol IT13 runs with the 3 button mouse- cominations of the mouse buttons do different intuitive functions - very slick once your use to it- middle button roller mice suck) When I was trained way back, by the true "old world craftsmen" in moldmaking, I was fortune enough to have a mentor that said "watch me, I'll show you how to do it. Be observant & you will learn."They guy was my father at work. It got to the point a few years later If I'd ask a question, Hans would say "move over & I'll show you" Ok ok I know how to run this machine I just had a question" He'd proceed & almost finish the piece I was working on. I would feel guilty if the boss would come out & see Hans doing my job! Alot can be learned by watching for me. Actions speak louder then words in my case. At the same to tokin BS artists can be cought in their tracks by saying to them" I don't know what you mean, can you show me?" Long story short, I evenulally became the foreman over Hans- when I was about 35. It was a very diffucult thing to comprehend at the time. How could I be my mentor's boss? Well it is easier than most think, took me a while to figure out. A good foreman does not really have to know everything, but knows & relies on others talents to get the job done, giving the right job to the right talents. Till this day Han's (now retired)could blow me away on an Advanced or Tryoke cross slide turntable on a Bridgeport. What I can program & do on a CNC blows him away. Its a complementary situation. Nobody knows everything. If they think so, well........let me tell you that no mater how much you think you know & how good you think you are, there is new situation coming that will knock you on your ass & throw you for a loop. I am always open to new ideas & suggestions. I don't know everything, but I can share my experiences with others & hopefully help before they fall on their faces like many of us do. Those who never make mistakes are usually those who never try. I always had the idea when I get older I'd like to tech guys getting into the trade at night school - community college, like some of the sharp people I looked up to when I was younger. That's not gonna happen due to our manufacturing economy being exported. Nobody getting into this trade. Hard to even find colleges with machine tool curriculum's such as mold making/ die making that I took as a kid. So here I am yak'in my fingers on the usenet group that I've lurked on for years with out much time to add, working 50-70hr weeks, behind a tube at work, who wants to come home & sit on the tube more? Things have sure changed, those 50-70 weeks are now at 40hrs if I'm lucky. The end of last year I was down to 4day 32hr weeks! Anyway drilling - taping - reaming in Cimatron is not one of my strong points but I do it occasionally. I bit of leg or elbow work is required to check the 3D model to insure proper drill depth, shorter on tap & reamer depths . Its not a big deal in mold work, we do'nt deal with hundreds of different hole sizes, depths, taps -ect. like production guys- thank god. I've had access to Hurco's & their conversational DXF translator is the cats meow for drilling, so allot of that work is handled on the shop floor at the machine while its running. In the old days, when CNC machines & CNC time were of short supply, I'd do allot of spot drilling & hand it off to the drill press or bridgeports for finish c-bore-taping ect- easy non critical work. It worked ok & keeped the CNCs cutting the harder 3D & close tolerance stuff they are good at. Till about 10years ago most mold guys just shyed away from drilling in CNC's due to their lack of knowledge on speeds & feeds & peck amounts. Water lines? out of the question, unless they are shallow - thats what gun drills are for. Ko's ? yes & no, its a matter of preference & gun drill availability. Naturally you don't want to drill 1/16 ko's in 25hp 50taper CNC. Its not that you can't again its preference & machine availability. Not all shops have 5 CNCs sitting waiting for work. If the spindles are not running, your not making money, plain & simple.
Anyway its now taken me all day to write this post, between church, rodding out plugged up drain lines & mothers day activities. I'm sure way off topic on metal finishing.
Anybody got some good high concentration blue diamond with gesswin 1200 stones cheap? I've got some die-cast aluminum corvette valve covers to do for wall hangers - memorabilia in the garage. Plus its much more fun than polishing out square corners in mold cavities 4" deep. Ha! I'm looking at the inside of the valve covers & the damn core are cracked! Thats the nice thing about die-cast molds, they wear/ wash out quick or crack so its replacement repeat - gravy work.
===================================================== ______ /_____/\ Best Regards, /____ \\ \ Gil Pawl /_____\ \\ / HOLDZEM /_____/ \/ / / /_____/ / \//\ West Chicago, IL \_____\//\ / / USA \_____/ / /\ / \_____/ \\ \ \_____\ \\ \_____\/ ======================================================Special alt.machines.cnc offer: Send me your mailing address by e-mail & I'll send you some Holdzem's for the cost of USPS, around $3-4 in US.
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On May 10, 7:39 pm, snipped-for-privacy@cin.net wrote:

Like anything else it's a learned skill.
You don't have to film it.
What I do is sit in front of the software and take notes every step of the way as I do what I want to write about. Here is a specific example of me doing that:
http://jonbanquer.wordpress.com/the-mastercam-handbooks /
What I'm asking you to do is put a bunch of points on the screen at the *same Z level* and then describe step by step how you would drill these holes to *different diameters and different Z depths* in Cimatron. What does the software present you with? How are different Z depths entered? What does Cimatron present you with for an interface while doing this?
I don't think it's that hard but I do think it requires a little time and effort on your part for something that doesn't come naturally to you.
Jon Banquer San Diego, CA
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Hmmm....... guess I'm still learning, but then again we never stop learning till the alternative happens

I do like that Masterscam guys demo training video to peddle his stuff. I don't have access to ver 9.?? so the engraving stuff I could'nt use. Thats all I'd use it 4. I'm sure I could do better than that & be funnier on top of it with Cimatron adding little digs to all the other softwares I've used & seen used by guys falling on their face or jumping thru hoops to do what Cimatron can do with a few clicks. That'd piss allot of people off. Its either that or I've been told I should write a book on my lifes follies? Any thoughts? Who'd buy it? Hell I can even get right of some damn Holdzems fer nothin!<g>

IIRC ( its coming back now) Cimatron can use points at the same Z level, It would require the user to create those points. - more leg work creating points- not a big deal, just an unecessry step. The way I prefer to drill is by selecting the 3D point- not point per say, but circle center point, at the bottom of the hole. That gives the correct depth automagicly! Natutally that point should be checked before hand to insure Mr solid model guy designed it correctly in his software. If is a "2D piece of paper cad file" drawing you'r stuck with the flat point(circle center) at top & you would manually enter the drill depth. You see there are so many variables as to what type of file your working with, determining how to proceed in Cimatron by selecting circle centers, line end points, physcal points, surface edge ect. Every job could be different, unless your getting the cad data from the same source all the time.

Once a depth is determined, either by 3D circle selection ( automatic) or manual input & physical point selection. The depth is modal as a global variable, just select the rest of the same type holes. If there are allot, I usually change the feature colors of all same type holes to the same color - a little leg work, but a snap to do in Cimatron. It keeps things eaiser to pick & straight in my head. ie: mask select all blue circles (1in deep) mask select all green circles (2"deep) & so on. Once all the selections have been made, 1 toolpath is created for each group of same holes. I copy those toolpaths as many times as needed for center drill, drill, tap ream, c-bore ect. tools & depths are changed manually but no reselecting of points are needed. There are some choices for optimization as far a path taken from hole to hole. I usually select the points in the order I want the machine to go.
What does Cimatron present you with for an interface

Very..............Hmmm........... I've been told archaic( by Pro-e guys). IT13 is not icon driven. buy buy all you windows pretty icon guys. The new version of Cimatron "Elete" is icon driven. I have not used it.

Like I said a video would be kwel. Think anyone would buy it? even if I thow in some Holdzems?<g>

\|||/ (o o) ______.oOO-(_)-OOo.____________________ ~ Gil ~ the HOLDZEM king Holdzem its the best thing since sliced bread ages 5-95 Everyone in the world can use a Holdzem! even people that don't like it can use Holdzem!
http://users.cin.net/~milgil/Holdzem_CAD1.jpg
http://users.cin.net/~milgil/Cimatron1.jpg
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280297868987&category=158950&sspagename=rvi:1:1v_
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On May 11, 6:27 pm, snipped-for-privacy@cin.net wrote:

Or, you could just use Mastercam and let it select all of the correct drill and tap sizes and depths, along with the correct countersink depths all automatically.

http://www.youtube.com/watch?v=RS0pRQX93lc

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wrote:

Link is not working for me error message reads:
"The URL contained a malformed video ID."
Tom
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On May 12, 11:36 am, snipped-for-privacy@aol.com wrote:

Interesting. I just clicked it and it opened right up.
Must have been because I copied it from the address bar instead of the "URL" box on youtube. Here's the correct one:

http://www.youtube.com/watch?v=RS0pRQX93lc

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