scraper shape question for narrow details

I am a novice scraper and have a course with Richard in April but in the mean time I am working on getting my equipment together. I can at least make and sharpen scrapers and would like to make one for a little exercise I have been working on. It is a drill press vise made from a rough casting. As it does not need to be scraped I think it makes it an ideal project to learn on before I go and mess up my schaublin 135 cross slide etc.

The detail is shown in the attached photos but is basically a 10mm (0.394in) wide flat with a slot on one side and shoulder on the other. Access with the current scrapers I have made is difficult. Do I need one that is very narrow, maybe pull type etc? I don't have to scrape this, I can get a very true and flat finish with my mill that will be more than sufficient for the project but figure I might as well figure out how it is done.

thanks

Luke

I think you will need to cut a relief in the inside corners if you want to scrape those surfaces.


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whidbey said:

I am a novice scraper and have a course with Richard in April but in the mean time I am working on getting my equipment together. I can at least make and sharpen scrapers and would like to make one for a little exercise I have been working on. It is a drill press vise made from a rough casting. As it does not need to be scraped I think it makes it an ideal project to learn on before I go and mess up my schaublin 135 cross slide etc.

The detail is shown in the attached photos but is basically a 10mm (0.394in) wide flat with a slot on one side and shoulder on the other. Access with the current scrapers I have made is difficult. Do I need one that is very narrow, maybe pull type etc? I don't have to scrape this, I can get a very true and flat finish with my mill that will be more than sufficient for the project but figure I might as well figure out how it is done.

thanks

Luke

Click to expand...

If you're using 1" x 1/8" flat you can taper the end. Grind a tight 2" - 3" radius and shave off a cutting edge. You should have a tool that will get you in most places with tight radius for splitting points / working small ares.

thanks guys, I will cut some relieve in the corners and make up a pointed scraper as described. I have a HHS saw blade I have been cutting slices out of, it should work for the blade with a bit of carbide brazed on the end. I am a little concerned the other side will get in the way but it will be easy enough to check and I need a detail scraper anyway.

Luke

Why be chicken and bring that part? I will be there watching you scrape. Challenge yourself and bring your lathe compound off your lathe. If you change your mind you can scrape it or at least we can talk about it. After you finish that simple part. Like Geir said, relieve the corner before scraping in there. Rich

no worries I am bringing the lathe parts, but before the class I would rather mess with things which are not expensive and hard to replace

I found a good use for a 3mm cutter in my drawer full of saw blades and similar this evening to relieve the sides of that slot and also added a couple more tools to the scraping arsenal. I now have a narrow push and narrow pull scraper to work with along with the larger radius push and Anderson Bros.

I really don't have much use for that Anderson Brother's scraper as my home made scrapers seem to work much better with their flexible blades. (I am using strips of a HSS saw blade with carbide silver solderd onto the end and then silver soldered into the end of a thin walled pipe)

L

I see you have an Anderson.....not my favorite... but they do work.

whidbey said:

I found a good use for a 3mm cutter in my drawer full of saw blades and similar this evening to relieve the sides of that slot and also added a couple more tools to the scraping arsenal. I now have a narrow push and narrow pull scraper to work with along with the larger radius push and Anderson Bros.

I really don't have much use for that Anderson Brother's scraper as my home made scrapers seem to work much better with their flexible blades. (I am using strips of a HSS saw blade with carbide silver solderd onto the end and then silver soldered into the end of a thin walled pipe)

L

Click to expand...

uhm it is the easy way cutting it, but i think it should have been like this.



dee
;-D

For a drill press vise I think it will do

whidbey said:

For a drill press vise I think it will do

Click to expand...

Yes but as you said, it could have just been milled too Personally I would have used a slitting saw at a 45 degree angle, it's good experience in setting up to do so, and may identify clearance issues with your saw etc that you hadn't foreseen.

This is the scraper that I use for dovetails and other tight spots. In use I will only use either the left or right corner, so the top is ground with a curve on it to provide relief when the scraper is tilted. It's hard to see in the photo, but there is a working radius just in from the corner, it's a dark band on the RH corner if you look carefully at the photo.

Thanks for the picture, I will make a single edge scraper like that as well. I had planned on doing so but made a double sided one instead.

I already know I would have had clearance issues with that blade and arbor at 45 degrees. I think I will need to find another arbor for slitting saws that has internal threads and a short bolt head. A larger blade would also do the trick I suppose. I have a number of different sizes but the larger ones are rather thin. I suppose I could also put the high speed head on the machine and cut it with a 2mm endmill.
L

Yes that is the type of thing that's good to practice on something like that. You can always make up a slitting saw arbour. They don't require any great precision as the saws will always have runout. If you relieve the centre part you can make a large but thin washer for the end, yet still have plenty of room for the fixing screw. The saw will be able to get down as close as the thickness of your washer.

Here's a photo of cutting a relief groove in a top slide. The setup wasn't as sketchy as it looks in the photos.

funny you suggest making up an arbor, guess what that round thing in the second photo I posted in first post is It is roughed out for a iso30 face mill holder but maybe I will make a special saw blade arbor. It is made out of a mystery 50mm stud I picked up here in Norway (offshore fastener, so probably L7 steel) It machines ok but the chips like to wrap around the part a bit much.

L

The Danish and Norwegian classes are being held at a job shop, so if you don't have the right equipment I am sure they will. Jan, a few others and I who are not new to scraping will have the right tools. Many times I use a hack saw or corner of the scraper to cut that relief, so no big deal, but a circle saw in a mill or cut off wheel in a hand held air grinder works good as long at you don't cut it to deep or wide to allow crud and chips in there, Just cut it .010 to .020" deep. Also we file the corner off so it's not sharp (.064" to 032") of the mating surface so it doesn't hit.

You may make and install way wipers as many old machines expected the machinist to wipe the chips off and oil the ways before moving them and didn't install wipers. Or as I have said if they world war 2 machines were expected to run for a few years to win the war and not last for long and wipers weren't that important.

You will discover during the class much of this is simple and not so critical. No worries as this is not rocket science. For years many made it sound as if it was and scared a lot of people away from it with all the harsh advice or to much info that overwhelms. There are rules you must follow, it's like rules of the road, You study it, start to drive, may have a few close calls when your young, if you don't take it easy you might have a fender bender or crash or two, but if you follow the rules you could drive (scrape) for years and not have a crash. Some people make you nervous with all the advice but if you follow the rules and practice you will do OK. Have to learn at your own pace and It's is much easier to learn when you have an instructor in the car with you too :-) Have a good day . Rich

Another thing when scraping down in a box way like that draw a imaginary line or a pencil line down the middle and scrape 1/2 of the surface from the middle to the side at 45 degree to the part and then flip it 180 degree's and scrape the other 1/2, stone it and then do the whole thing again at 90 degrees of the original scraping to get the checker-board look. Also do the Richard King 4 Scraping rules. The Texas class added 3 more rules....lol

You can make scrapers to suit any job scale. Back in he day I made a scraper from an old screwdriver and a little pieced of carbide to scrape in tiny little patches in a deep recess (frog seats inside a cheap Anant hand plane body - yeah, I know: anal. But I was dazzling the local woodworkers always slobbering over their Stanley Bedrocks)

The trick is controlling the scraper so you don't dig in the corners.

If you match the tools and technique to the scale of the job all that remains is patience and backache.

Richard King said:

Some people make you nervous with all the advice but if you follow the rules and practice you will do OK.

Click to expand...

Like a lot of things Rich, it's easy when you know how. I personally have no problem in my day job in guiding a million pounds worth of aluminium and human flesh from one side of the planet to the other, but I never forget that after 30+ years I'm still very much a student at that too. Others here would have held a beating human heart in their hands, while still others can use a sharpened piece of sintered material to align complex geometry to within the limits of practical metrology

When faced with uncertainty a lot of people will seek re-assurance from people who have been there before. Some of us are keen to pass on that experience and encourage others to take the next step too. Some of the "advice" (and I hesitate to even call it that), more personal experience, that I personally provide may not be the best way, it may not even be a good way, but hopefully it's never bad advice and it's certainly worked for me. My attitude is that someone will think that if a Bozo like Pete can do it, it should be a walk in the park for them. Similarly I like others to show their experiences too, and it will often provide the confidence to me that if I can see they can do it, and they provided photos to prove it, I should be able to do it too. I'd rather see a few photos of somebody having a go at something, than yet another tome from some forum members about what a hero they are who, surprise surprise, have never once produced anything tangible here to backup their claims. Frauds are right up there with Fake News I'm afraid. It's why I like how you provide pictures of not only your own work, but those of your students too.

We're all just students in life, some get it, some don't.

Maybe help full maybe not,( you said you used a saw blad)
I used a old hss saw blade to build a scraper, the edge lasted about 2 scrapes.

Andy in the last class (Texas) used a hack saw blade installed in a hack-saw and relieved the corner of his lathe compound. One of the other students held down the middle of the flimsy blade with a chunk of wood, I should have taken a picture... If you own a Connelly book look at page 11 sec. 4.2 and it shows how they make a groove cutter out of power hack saw blades. I had one once and it worked so so. On page 59 it also gives examples of the relief grooves. It's simple once you have done it a few times. Did you temper the power-hack saw blade by heating it to a cherry red and oil quenching it? That should have helped make it harder then a regular blade. I used to do that to files way back when...1960's when I was learning to scrape and made knifes when I was a kid.