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Drill after scraping?

Nhan863240

Plastic
Joined
May 27, 2023
Will the piece keep it flatness if I drill it after scraping? Given that all the burr from drilling will be get rid of.

Im trying to scrape a piece that will have small holes, but i figured it would be more difficult scraping it with holes so im trying to to find a way to work around.

Thanks in advance!
 
Will the piece keep it flatness if I drill it after scraping? Given that all the burr from drilling will be get rid of.

Im trying to scrape a piece that will have small holes, but i figured it would be more difficult scraping it with holes so im trying to to find a way to work around.

Thanks in advance!

Nhan,

I see you’ve gotten no response to your question.
There are likely a few reasons that no one has piped up.

First you need to give some dimensions to the scraped object, and the number, spacing, and location of the holes. Are they through holes or 1/16” deep?

What is the condition of the material are you scraping? Has it been properly thermally stress relieved?

Most likely very few people have experience drilling scraped iron surfaces after they have been scraped, so they are reluctant to simply speculate.

I have no experience drilling scraped surfaces, but I do have some general knowledge of cast iron and it’s expected behavior. My guess is that ten holes representing less than 1%. Of the total volume of the object and widely spaced and not too near edges would PROBABLY have little affect on the overall flatness.

Unless someone has a fair bit of experience with this process and has some rule of thumb for guidance, you may need to simply try it and find out.and report back. It seems likely that any warpage of the surface should be small and require only minor touch up—-again, speculation.

Denis
 
There's no reason why drilling some small holes in a scraped face would make any dimensional change, so long as the drill was sharp and/or the corners broken. You might conceivably raise a hump around the hole if you had a poorly ground or blunt drill. Personally I always countersink holes in the face just to be sure.
 
There's no reason that drilling some holes in the material should matter to flatness as long as you stone the burrs afterwards. Now if you're turning it into swiss cheese, that's a different story.
 
There's no reason that drilling some holes in the material should matter to flatness as long as you stone the burrs afterwards. Now if you're turning it into swiss cheese, that's a different story.
Makes it real difficult to answer a question that is stated only in pretty vague terms and then no clarification is offered despite several requests for more info. Post #1 is the first post and only post from this member.

Denis
 
Sorry for missing this question as I broke my arm and it's a real pain typing or answering all the posts.
Many of our members own a copy of the Edward Connelly book "Machine Tool Reconditioning" . It's an older hard cover book - Copyright in 1954 and over 500 pages. We call it the Bible (its red more like a hymnal) of Scraping and Rebuilding. . The book was written by Several as Connelly acknowledges; People from companies and Universities in the first few pages. On pages 33 and 34 they explain how to scrape holes and slots. As Dennis wrote, not knowing size of the holes is the answer is a guess. The book says to attack on a straight angle an not on an angle as that could round off the edge. You want a flatter blade radius too. Now if it is a lubrication hole you want it chamfered so the oil flows out.

If you don't have a copy you can buy them. I sell them on eBay, but there are other sources. If your new and want to get a fast start, I teach How to Scrape and sell a DVD also on eBay. I have a class next week in Minnesota that my son will be teaching. post the dates in the forum too. The net after that is the first week in October. Hopefully I will have recovered from my accident for that class.. You can also see info on my classes inside the DAPRA.com website. They also sell the book. I will offer the members a discount if you want a copy, DVD or USB stick on my stuff. :-) Rich
 

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I have 10 of the "good' pills left, lol . I'm taking Tylenol only. I'm seeing outpatient therapy for my hand and arm at two different clinics. Both therapist say no pain no gain for around 8 weeks more as long as I do the home exercises 3 times a day, I did them 4 times a day. also my hand therapist said it would be OK to bandage my bad hand in a fist I did it twice today. that smarts, but I want to be able to scrape and go fishing the middle of september and teach the October class.
 
Hi Rich, that's great progress, just keep at it and try and do stuff that you enjoy so much that you don't care if it hurts. If it doesn't give you stomach problems, you might find that ibuprofin works better than Tylenol (aka acetaminophen/paracetamol). Cheers, Bruce
 
Hi Rich, that's great progress, just keep at it and try and do stuff that you enjoy so much that you don't care if it hurts. If it doesn't give you stomach problems, you might find that ibuprofin works better than Tylenol (aka acetaminophen/paracetamol). Cheers, Bruce

I cant take iubrofin as it effect my blood clots. I have a condition called Factor 5. One of the main reasons I stopped teaching in Germany. Damn long plane rides . I take warfin blood thinner . daily and will for the rest of my life. The last class in Austria I got one in my left leg. Stefan took me to the ER - I told Biax that was my last trip. We planned to have Stefan and Franz to host and I would still teach a few more times. I have a cabin in Northern WI and want to go fishing and teach some more classes...My passions and can't be done with a bum arm. thank for your concern :-)
 
I cant take iubrofin as it effect my blood clots. I have a condition called Factor 5. One of the main reasons I stopped teaching in Germany. Damn long plane rides . I take warfin blood thinner . daily and will for the rest of my life. The last class in Austria I got one in my left leg. Stefan took me to the ER - I told Biax that was my last trip. We planned to have Stefan and Franz to host and I would still teach a few more times. I have a cabin in Northern WI and want to go fishing and teach some more classes...My passions and can't be done with a bum arm. thank for your concern :-)
A bad day fishing is better than most days working.
Do the relaxing days while you have them.... but if only I could take my own advice. :)
Be well. You have done much for the world.
 
I scraped today First time since the accident Yayy...We are doing a class in my backyard shop and one of the students was having a hard time scraping individual scrape marks, So I awkwardly picked the Biax up and showed him for about a minute,,,that was as long as I could hold it up.....Was fun.. :-)
 
I scraped today First time since the accident Yayy...We are doing a class in my backyard shop and one of the students was having a hard time scraping individual scrape marks, So I awkwardly picked the Biax up and showed him for about a minute,,,that was as long as I could hold it up.....Was fun.. :-)

Old joke about the guy asking his doctor if he'd be able to play the piano after his hands healed.

Doctor says, "Yes, of course."

Guy says, "That's wonderful. I never could play piano before."

You had a long head start and it's good to hear that skill is still right there. Knock on wood, the stamina and pain subsidence will come too.
 
Yesterday to my surprise I showed the students how to hand 1/2 moon flake. My left arm ached but I was able to hit the hand flaker with the dead blow hammer. Then I stood back and told them what they needed to do. Both JD and Howard figured it out in 10 minutes. I also showed the how to scrape Turcite. I'm still a long way to being back to normal as my injury hurts like heck. with my broken shoulder is nothing compared to the injured solders out there. God Bless them !
 
Hey Rich,

delighted to see that you are getting better. Something I have learned in recovering from past accidents: pay attention to the difference between "ache" and "hurt". When you do something and it makes you ache, that is good. You are stretching those joints and muscles, and if you keep at it in a regular way and don't overdo it, they will loosen up and you'll get more motion and less ache. On the other hand pain means stop: you are doing harm. So if it hurts, just stop and try again another day.

Brief summary: ache = good, pain = bad.

Cheers,
Bruce
 








 
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