How thick are Biax scraper blades?

[Mark Rand]

If you look at steel specifications (https://matweb.com/ is a very good reference), you will find that any steel alloy you can find will have a Young's modulus of approximately 200GPa.

 

[Bakafish]

I did see that, but it is also very close to dedicated spring steels, so maybe Young's Modulus alone isn't the best way to choose the proper steel (I'm no metallurgist), my measurements are not accurate enough, the value is more critical than I understand or it doesn't matter and any steel can be used. I wasn't trying to prove anything, just provide quantifiable data that may be useful to someone trying to make one of these.

What I do know is BIAX goes through a lot of trouble to splice together two different pieces of metal with a finicky little slot and brazing. They are not a corner cutting company, these are not cheap, they can afford to make them this way. Maybe this brazed joint is superfluous or makes sense for some tangential manufacturing reason, but my assumption is that the blade is a different material than the shank and it is chosen for some specific properties that make it worth the trouble.

 

[TGTool]

Don't forget that the blade mounting includes that rubber piece which introduces compliance. I'm guessing the the difference in action and feel is more from the length difference than the holder flexibility itself. A short stiff holder for muscling off material and a longer one for finesse.

And I'd side with Mark in thinking material used for the holder is insignificant compare to geometry. I've made both hand scrapers and Biax blade holders from hot rolled steel and the only problem I've ever encountered was bending a narrow, long hand scraper by leaning on it too hard. So I just bent it back and went at it a little more gently.

 

[lucky7]

Others got the blade measurements before I got to my shop, so assume the OP has the info he needs?

Got to admit I disagree with some experts and prefer a stiffer hand scraper. Love my tubular Andersons. Yes, it’s easier when first starting to get decent results with a flexible handle, but once a guy learns muscle memory to start each stroke with minimal down force and end with same, all your energy goes to making chips, not bending the handle. Only downside is more frequent sharpening. Agree, geometry is key.

 

[Bakafish]

Don't forget that the blade mounting includes that rubber piece which introduces compliance. I'm guessing the the difference in action and feel is more from the length difference than the holder flexibility itself. A short stiff holder for muscling off material and a longer one for finesse.

I have a rigid insert type holder of similar length to the flexible blade and it feels much different, the flexible blade really flexes, it's not the same feel at all despite both using the same rubber shoe. I am not disagreeing that a home built flex style unit can't be made similar or identical to the factory blades (better even), I'm just saying I would trust such a conclusion more if it was tested side by side or we had more details on the steel used by BIAX.

And I'd side with Mark in thinking material used for the holder is insignificant compare to geometry. I've made both hand scrapers and Biax blade holders from hot rolled steel and the only problem I've ever encountered was bending a narrow, long hand scraper by leaning on it too hard. So I just bent it back and went at it a little more gently.

I suspect very much that the carbide would snap off before I could bend the factory blade. The question is, can you make a similar blade out of mild or annealed tool steel that have the same performance. I asked Mark to share the actual dimensions of the units he made, I was hoping he would be interested enough to test his tools similarly so we can determine if the amount of deflection will be similar to the factory blades. There's plenty of speculation (I'm as guilty as anyone) so why not get to the bottom of it?

 

[Bakafish]

Others got the blade measurements before I got to my shop, so assume the OP has the info he needs?

He likely regrets asking the question at this point

My blades are pretty old and may not represent newer designs, so any info you can add on dimensions materials or construction that differ from what I showed would be interesting to me anyway.

Got to admit I disagree with some experts and prefer a stiffer hand scraper. Love my tubular Andersons. Yes, it’s easier when first starting to get decent results with a flexible handle, but once a guy learns muscle memory to start each stroke with minimal down force and end with same, all your energy goes to making chips, not bending the handle. Only downside is more frequent sharpening. Agree, geometry is key.

The Tungaloys I have are quite stiff (and fairly short), although every Japanese scraping video I've seen seem to use shop made monstrosities that are used in ways that make me highly uncomfortable. Japanese style scraping form is borderline indecent. The Tungaloy inserts are top notch though, and still available. They also make a carbide taper spindle scraper which I think is really hard to find these days.

 

[cuttergrinder]

I sharpen biax scraper blades for a company and they are solid carbide. They have 3 different widths and each width has a different radius that I grind. They have to be really sharp. I grind them with a radius fixture and a diamond wheel. They use them to scrape the ways of large roll grinders for the steel mills

 

[stephen thomas]

I found pictures of the S7 shank i made. S7 is a good shock resistant tool steel for impact duty tools. The bit is M2 HSS. For scraping steel.

As has been noted, all steel has essentially the same Youngs modulus.
The difference is that harder steel is stronger, and will bend further before yielding and permanently deflecting.

So as Richard said, if you thin the low carbon steel shanks to much and lean on them hard, they will bend & more or less stay bent until you physically bend them back. Then they will bend again the next time you lean in.

The regular biax shanks with brazed on carbide tips are hardened, but i don't know the alloy. So you can bend them a good bit before they will yield and stay bent. I do not know how far you can bend one before it breaks.

This S7 shank simply flexes a bit, like a spring, and i ride it very hard. The steel shards come off like BB's and the motor is grunting the whole time. I do not pussyfoot around when trying to remove metal from a well work casting, or in this case, steel fabbed part. The reason i like the spring, is it helps the positive edge get under the chip, and then flick it up and off. Rather than stabbing and merely leaving big burrs. But either will work, you just change the angle of attack.

http://www.mwdropbox.com/dropbox/biaxinsertcutter1.jpg

http://www.mwdropbox.com/dropbox/biaxinsertcutter2.jpg

Some of Biax stock blades are thinned:

http://www.mwdropbox.com/dropbox/handscraper_styles5.jpg

some use a V joint, others a full mortise:

http://www.mwdropbox.com/dropbox/handscraper_styles6.jpg

These are some of the blades i made for the Andersen flat style handscrapers. Carbide silver soldered to mild steel shanks:

http://www.mwdropbox.com/dropbox/handscraper_styles4.jpg

After grinding, i intentionally broke 2 of them I could not break them with typical pressure, but smacking with impact broke the one with full separation. Really laying my whole weight on the other, actually trying to break it as opposed to merely a very heavy scraping effort, finally broke the other. These are only a butt joint, but it is accurate and close fitting.

http://www.mwdropbox.com/dropbox/handscraper_styles7.jpg

 

[Tillie]

Wow I did not expect there to be this much interest in the subject. I didn't think guys were still talking about it since thursday.

Yep those black 4mm biax blades I have are file-soft.
I was thinking about making the blade from mild steel in one piece and the same material for the clamp. Now I might try a few different options. Yes I'm trying to imitate Biax's design of their brazed blades and I have a few options for pre-hard alloy steel. I might then make a two-piece blade, 4mm at the end that attaches to the shoe and 2.5 for the rest. I'm still on the notion of a clamping type holder because I have plenty of sandvik 630s now and I like the idea of the carbides being interchangeable between any of my power scrapers and hand scrapers. also I understand the H2 grade of carbide being the right stuff for it's duty in scraping.

I prematurely made a smaller hand scraper for finish scraping (pin-pointing). It takes a 3/4 wide C2 carbide rectangle. I say prematurely because I only started actually scraping about a month ago. Pin-pointing is ahead of me yet.

Steven thanks for showing all those blades you made I have enough ideas to get started.
I'm going to make something first so I can keep going, and then experiment with other designs.

 

[Richard King]

You can also get info from DAPRA.com and BIAX.com They show the blades under the scraper part of their website. You can look...they are expensive, but the real McCoy.

 

[ballen]

I posted this on the other forum, but here it is for complete saturation:-
20mm x 3mm is what fits my BL40 and what I use for all my blades. Brazing/hard (silver) soldering a carbide blank onto the end of a bit of metric gauge plate makes a good blade.

Blade looks good. What is "metric gauge plate"?

 

[Mark Rand]

Blade looks good. What is "metric gauge plate"?

O1 ground rectangular bar. AKA 'ground flat stock'. Normally sold ground to a reasonably accurate thickness, but width is not always ground for thinner sections. The rectangular equivalent of silver steel.

 

[Tillie]

It's been a couple of months but I finally got around to making a blade. I had a couple other projects to finish first but it's time has come. And I don't want to be the guy who talks about projects here and has nothing to show for it.

I went with a brazed-on type, 6" long with a 1-1/4 bit of C2 carbide. I ground and lapped the tops and fronts up to 3000 grit, with a 60mm radius and neg 5 degree relief. I use a shop-made slow speed grinder that takes 6" lapidary disks. Somehow using these cheap disks the tops of the carbide still don't come out looking like a sandvik 630 as far as the degree of polish .

The blade is a strip of O2, 1/8 at the ends and 2mm in the middle. I filed a Vee in the business end and ground an inverted Vee in the bit to mimic the biax design and give the brazed joint more surface area.

Once it was all done I tried it out in the power scraper on a peice I had been hand scraping. I'm used to those rigid blades so I'm not sure but 2mm might be too thin and flexible. It definitely flexes when putting "15 Lbs" downward pressure into the stroke. Clearly I've scraped a concavity in the workpiece.



I made two other blade blanks from the same stuff. I might harden one before brazing (although it should be thicker than 2mm or might crack) and I might make an insert-holder of the other or both.

 

[CarbideBob]

... I use a shop-made slow speed grinder that takes 6" lapidary disks. Somehow using these cheap disks the tops of the carbide still don't come out looking like a sandvik 630 as far as the degree of polish .

That is weird. At 3000 grit you should be able to read the writing off the Florescence or LED tubes 12 feet up.
This is one of our rough checks that things are working.
Look at the that light bulb tube up there using the part as a mirror. If it bends that says something. If not clear that says something.
This is actually a real simple and great part check to let you know things are playing well.
The spec here is 4RMS or better. Generally it runs two.
Maybe your grit is too fine and things are wobbling.
I am more in 1200 grit for tops and 800 grit for the super fine finish on the flanks in carbide.
Blades of this type. 1200 on a Blanchard top and bottom (we rough to size on a 120 wheel). 240 grit on the back and sides. 800 grit on the working end.
Of note here. On the front grind the carbide being ground must be in compression or side ground or it will chip out.

 

[Tillie]

I like that check- reading the writing on the lightbulb. The backing plate on my grinder is definitely wobbling- I have to pull the shaft off and re-face the backing plate that the disks mount to. I might check the disks themselves too, although the shush-shush sound seems about the same on each.
In any case, the carbide does the damn thing when put to iron, so my surface finish is not stopping the show.
I may think about this differently if I had the chance to use a Glendo grinder, but I may also think about driving differently if I had the chance to drive a Lamborghini. or a tractor

 

[Bakafish]

I may think about this differently if I had the chance to use a Glendo grinder, but I may also think about driving differently if I had the chance to drive a Lamborghini. or a tractor

Why choose when you can have both?