Carbide blades or high speed steel blades for scraping?

I was wondering if Carbide was worth the expense and trouble over high-speed steel for scrapers. Given you are not removing a lot of matierial with this method and it's more about precision than moving materail.

Sharpening carbide is harder than HSS.

SirRage said:

I was wondering if Carbide was worth the expense and trouble over high-speed steel for scrapers. Given you are not removing a lot of matierial with this method and it's more about precision than moving materail.

Sharpening carbide is harder than HSS.

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Wearing-out the edge you just sharpened - again - is far, far harder on the Carbide, too. No contest. Been covered. Carbide is the go-to for precision scraping or even roughing.

I no longer want to use HSS even for scraping old paint, the Carbides are so much better. Seriously.

Getting set-up to sharpen and hone Carbide scraper blades is not expensive. JFDI.

I think if you take the time to read back in the forum discussions you will discover that Carbide is the best tried and true method. It has to be sharp and honed to a fine edge to work properly, you will find discussions on that too and how to achieve a proper edge.

Can you use HSS? sure, they did for years. If you have plenty of time and like to hone more than scrape HSS could be for you. Like Bill says, you can with the help of eBay find very inexpensive high quality diamond laps and build a laping rig fairly cheap.

I agree with Bill and Warren. I used to lap HSS blades when I was a kid 50 years ago. We held the handle vertically and over about 5 deg and moved it back and forth on a longer sharpening stone mounted in a 2 x 4 that was routerred out to hold the 1 x 2 x 10" (approx size) medium grit Indian Stone. We also flipped it and lapped the flat sides to really polish the blade so we didn't get mini scratches in the cut. Chapter 5 in the Connelly Book shows this vintage method. I showed a student to do it in a class and that was the first time I did it that way in 45 years. In the late 1960's we advanced to using Anderson Carbide blades as we used Anderson Scraper back then too. Then we bought Sanvik Scrapers and blades and a 300 grit diamond face wheel we mounted on a double end Baldor tilt table grinder. We used this method until the late 1980's and when diamond wheels were a bit more affordable, we bought a 600 grit wheel.

Then at an IMTS show where I demo'ed BIAX scrapers for DAPRA is where I saw a Glendo Accu-Finish lapper and I bought one with 260, 600 and 1200 grit lapping wheels. I never considered HSS after that.

Check this out. We are discussing scraping and lapping ..scroll to #65 to see the set up.Also see the longer scraper handle and clamp in Sanvik Insert. As the others have said we have wrote about this dozens of times before, but you new guys haven't been here. But as Lazlo and old member 10 years ago showed me, you Google your question and put Practical Machinist on the end of the search and you will see all the old posts.

You also need to rough grind the blades those carbide insert blades on a green wheel or the 260 grit diamond lap
before finishing them to a 60 radius 2.3" diameter circle. Matt C just took a drafting compass and drew circles on a piece of paper and laminated it and he uses that as a guide. I never use more then a 90 mm or 3.5" circle. (wife bought me an Alexa for Xmas..sure works great for figuring out the math, I just ask her/it to convert mm to inch and she tells me, no more calculator)

I rough scrape using a radius 90 mm / 3.5, finish scrape at 60mm /2.3" and point spot/technique 40 PPI with 40 mm/ 1.57" or 20 mm / 0.79 " for super small and narrow and short cuts. Scroll to pos 65. :-) G-Day Rich

http://www.practicalmachinist.com/v...-rhu-450-1960s-343863/index4.html#post3108497

SirRage said:

I was wondering if Carbide was worth the expense and trouble over high-speed steel for scrapers. Given you are not removing a lot of matierial with this method and it's more about precision than moving materail.

Sharpening carbide is harder than HSS.

Click to expand...

Carbide is MUCH better than HSS in almost all situations - far superior. For one, lasts a couple of times longer. Some cast iron can be viciously hard - I had to sharpen a 14mm drill bit twice to go through the wall of the ram of my MAHO. And it's not that thick.

The bloke who showed me how to scrape did not use carbide, did not like it. He had a peculiar procedure to sharpen HSS which worked well enough for him and I must say the result was very pretty - every facet was mirror like. But I can't say if that improves functionality in any measurable way. Myself have tried both and I'm sticking to HSS as I like the positive feel, low pressure and control of a super sharp HSS blade. It's a bit like with knives and chisels : the sharper they are, the more control you have, the less chance to wonder into the cut and onto your fingers. The penalty is frequent touch ups.

SirRage said:

Sharpening carbide is harder than HSS.

Click to expand...

Sharpening WAS more difficult (or more expensive) than HSS 50 years ago.
I don't know how many times I dare to mention these chinese inexpensive lapidary diamond grinding disks..

3pcs 6" Inch Grit 24# 6# 3# Diamond Coated Disc Flat Lap Wheel Lapping | eBay

1/2" mounting hole matches cheapest horror freight(tm) grinders. For optimal results might consider slower speed than ordinary grinder but I haven't seen any difference between 300rpm and 3000rpm. Just go with very slight touch on finishing pass at 3000 grit wheel. 3000 grit is actually the only one you need for re-sharpening, 240 or 600 grit is only needed when you change the shape/radius.

Carbide for me every time. If only for the reduction in time between sharpenings.

Regards Tyrone.

Here's a number you can take to the bank: a carbide scraper edge lasts about 20 to 50 times longer than HSS..

Carbide scrapers needn't be expensive. You can make your own scrapers. A piece of carbide 1" x 1/4" x 1/8" costs $7.16. MSC is one source.

Rectangular Carbide Blanks - MSCDirect.com.

Lap the 1" x 1/4" faces to a mirror finish on a diamond lap like this (also homemade):

Shop Stuff: Scraping Class (second image down)

Silver braze the carbide on the end of a homemade shank shaped like a file and grind/lap the end radius.

The basic scraping resources (make the lap from shop junk, stock the materials, etc and make a few scrapers) cast about the price of a new Sandvik factory made carbide scraper and carbide blade. Once you've accumulated the scrapers, sharpening equipment, etc you're pretty much set for life for basic scraping equipment. (not counting scraping references: a separate item).

All this depends on the situation as if you are working on a customer's machine or not. Power scrapers turn a 40 hour job into 20 hours or less, hss blades are worthless on a power scrapers. With hand scraping I tend to use both working on my own equipment. I do like Rich Kings idea of the long flexible carbide blade handle as they work really well.

Is it possible to retrofit an HSS insert from say Anderson onto a Sandvik hand scraper?

I like the clamp style scraper of the Sandvik but can't seem to find hss inserts readily available except at anderson.

radiocontrolhead said:

can't seem to find hss inserts readily available except at anderson.

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That should tell you something.

I just checked with Dapra.com and they have HHS inserts in stock that are sold to scrape steel. They have a positive rake, but you could grind them flat like a regular blade with 2 sided 5 degree neg. Made in Germany 3/4" x 1" is $61.40 and 1 1/4" x 1 1/2" $57.30 (older stock, so cheaper) . They would fit in a Sandvik. I bet Carbide Bob could make you some. I used to make them out of cut of blades years ago. Have to be super careful with HSS to not get them hot when grinding. Dip them in water a lot when hand grinding. Also when lapping squirt oil on the stone.

If you own a Connelly Book look on Page 19- 24 and they described how to heat threat and quench blades, grind and stone sharpen them . I know someone who sell the book. PM me if you want one. Rich

radiocontrolhead said:

Is it possible to retrofit an HSS insert from say Anderson onto a Sandvik hand scraper?

I like the clamp style scraper of the Sandvik but can't seem to find hss inserts readily available except at anderson.

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Woodworking thicknesser plane blade would provide material for lots of HSS inserts.
ie something like this: W585/1 Planer Thicknesser Knives 31 x 3 x 3mm HSS

Chop to pieces with thin disk and angle grinder. Cobalt containing grades are quite workout for the angle grinder.
Getting hot and soft I have to somewhat disagree with Richard King.

If you feel nostalgic you can also make your scrapers from carbon steel. Works "ok" on clean mild steel.
Super easy to sharpen and super fast to dull during use.
(Carbon steel is the one you have to be carefull not to overheat during grinding)

Matt ....lol... It's OK to disagree with me...lol...Hell I screw up just like everyone else does. Always 2 ways to skin a cat... Plus I have not worked with HSS blades of any sort in more then 40 + years accept demoing in classes for maybe 5 minutes. Times and technologies change. From when I was using them 40 years ago I spent almost as long sharpening them (or the old Anderson and home made ones) and every now and then had to heat them back up to cherry red...1650 F and quench them in oil as they seemed to get soft again. We used to shape them on a fine white wheel grinding stone and then lap them. Matt teach us please on these new HSS blades please. Forrest What say you? :=)

I believe that the Anderson blades are high carbon steel, not true HSS. At least the one I have.
I would expect that 1/16" or thinner blades (like the ones used on Anderson scrapers) made of true HSS would become too brittle. Possibly, O1 steel (which it is on the boundary of being a HSS steel) could be tempered to retain enough elasticity. As far as I know, there is not much control on tempering air-hardening steels.

Paolo

Richard King said:

Matt ....lol... It's OK to disagree with me...lol...Hell I screw up just like everyone else does. Always 2 ways to skin a cat... Plus I have not worked with HSS blades of any sort in more then 40 + years accept demoing in classes for maybe 5 minutes. Times and technologies change. From when I was using them 40 years ago I spent almost as long sharpening them (or the old Anderson and home made ones) and every now and then had to heat them back up to cherry red...1650 F and quench them in oil as they seemed to get soft again. We used to shape them on a fine white wheel grinding stone and then lap them. Matt teach us please on these new HSS blades please. Forrest What say you? :=)

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Sounds like you have been working with plain old high carbon steel.
-HSS doesn't soften until around red hot ie. takes about 1200f to considerably soften HSS: page 3 tempering chart: http://www.bucorp.com/media/M2_data_sheet_09032013.pdf
(room temperature) Hardness actually increases until 1000f or so

-HSS hardening typicall also needs more than 1650f cherry red. 2100f and "orange hot" is more about right for HSS.


Whereas carbon steel starts to soften/anneal as soon as you get tempering colors (straw...blue) and cherry red would be the hardening temperature.
HSS haven't been new since World War number One

So I won an auction on a 620-20 sandvik scraper on Ebay! yay! i'm stoked and ideally i'd like to run carbide with it but want to wait and experiment with the good ole steel first. I generally like to climb up the stairs even if i know whats at the top of the flight to keep things interesting. Anywhoo. Will the steel below be hard enough for scraping? I intend to obviously cut them into insert sizes and simply attach to the scraper.

18 Inch Long x 3/4 Inch Wide x 3/16 Inch 81173585 - MSC

Found additional information on the type of steel:

AISI/SAE 415 Alloy Steel: Forging Facts & Characteristics | All Metals & Forge Group

Also mcmaster sells 01, a2, and d2, for relatively inexpensively as well...

radiocontrolhead said:

So I won an auction on a 620-20 sandvik scraper on Ebay! yay! i'm stoked and ideally i'd like to run carbide with it but want to wait and experiment with the good ole steel first. I generally like to climb up the stairs even if i know whats at the top of the flight to keep things interesting. Anywhoo. Will the steel below be hard enough for scraping? I intend to obviously cut them into insert sizes and simply attach to the scraper.

18 Inch Long x 3/4 Inch Wide x 3/16 Inch 81173585 - MSC

Found additional information on the type of steel:

AISI/SAE 415 Alloy Steel: Forging Facts & Characteristics | All Metals & Forge Group

Click to expand...

Nope, pre-hardened (or actually hardened and tempered) 4142 is nowhere hard enough for scrapers. At around HRC30 its easy to cut with hss tools.
Not good even if you harden it.

Look for O1 type steel if you want to start with 100 years old tech, O1 must be most common tool steel in US.

MattiJ said:

Nope, pre-hardened (or actually hardened and tempered) 4142 is nowhere hard enough for scrapers. At around HRC30 its easy to cut with hss tools.
Not good even if you harden it.

Look for O1 type steel if you want to start with 100 years old tech, O1 must be most common tool steel in US.

Click to expand...

Saweet,

Will do. I'll go ahead and place an order on McMaster which has exactly what I need.

Forrest Addy said:

Here's a number you can take to the bank: a carbide scraper edge lasts about 20 to 50 times longer than HSS..

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Yes that is probably about right.
I'll use HSS for bearing scrapers like when rebuilding a Cincinnati centerless or OD grinder spindles but carbide is just so much faster when doing ways or making mounting surfaces.
One problem with HSS is that since you do not want to go and resharpen you will keep going with a dull edge and fight it for too long.
Problem with carbide is that some can't resharpen so you have to send the bits out.

61 bucks for a HSS tip from a stocking source seems so way high. I know it's a one piece order so mostly sales, stocking, packing, etc but is a carbide bit this high from them?

Here is the very weird thing.
Given a choice of making it from carbide and HSS, raw material costs and the way both grind to a fine edge, I'd likely be cheaper in carbide.
Bob