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How to finish scrape with Biax?

ewlsey

Diamond
Joined
Jul 14, 2009
Location
Peoria, IL
I finally bought a Biax power scraper. Now I'm looking at my hand scrapers the way I looked at my bicycle on my 16th birthday...

Anyway, I'm getting the hang of it. I think I figured out the roughing. I used a long and flexible blade with a wide nose and large radius and a 15mm stroke length. That got me roughed-in in short order. But I'm not sure how to transition into finish scraping to break up the large high spots and get a better distribution of points.

Do I just shorten up the stroke and try to move a little faster?

IMG_1091.jpg

Also, this is a Chinese angle plate and I ran into some inclusions in the casting that are hard as a coffin nail. The carbide scraper will not touch them. Does anyone have tips to deal with that? I might try an angle grinder just to see if I can bring them down a bit.
 
Shorten your stroke and slow the speed down. Go for individual points. To me it looks like you stoned the part flat with little depth. You will have a difficult time reading the blueing with out depth. Remember individual scrapes, focus on rows to get the checker board pattern. Once i figured out rows it came easy.

Also sharpen to a smaller radius for finishing. A small radius will help you get depth and rifle like accuracy.
 
I finally bought a Biax power scraper. Now I'm looking at my hand scrapers the way I looked at my bicycle on my 16th birthday...

Congratulations!

Anyway, I'm getting the hang of it. I think I figured out the roughing. I used a long and flexible blade with a wide nose and large radius and a 15mm stroke length. That got me roughed-in in short order. But I'm not sure how to transition into finish scraping to break up the large high spots and get a better distribution of points.
Do I just shorten up the stroke and try to move a little faster?

Yep. That's exactly what I do. You're on the right track in my estimation. Also, a smaller radius so you can break up the individual points in effort to get more distribution.


Also, this is a Chinese angle plate and I ran into some inclusions in the casting that are hard as a coffin nail. The carbide scraper will not touch them. Does anyone have tips to deal with that? I might try an angle grinder just to see if I can bring them down a bit.

Again, you're on the right track. I have had the exact same experiences with those same plates.

Congrats, again.
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I"m sure other more knowledgeable people will chime in as well.

( EDIT - Looks like MCritchley was posting while I was writing ) :)
 
I finally bought a Biax power scraper. Now I'm looking at my hand scrapers the way I looked at my bicycle on my 16th birthday...

Anyway, I'm getting the hang of it. I think I figured out the roughing. I used a long and flexible blade with a wide nose and large radius and a 15mm stroke length. That got me roughed-in in short order. But I'm not sure how to transition into finish scraping to break up the large high spots and get a better distribution of points.

Do I just shorten up the stroke and try to move a little faster?

View attachment 198800

Also, this is a Chinese angle plate and I ran into some inclusions in the casting that are hard as a coffin nail. The carbide scraper will not touch them. Does anyone have tips to deal with that? I might try an angle grinder just to see if I can bring them down a bit.

Wes, I have what I think is the same two-DVD set - "Scraping for Alignment" from Mike Duck that I believe you have as well.

He 'seems to' do near-as-dammit the entire job with nought but the Biax. So 'yes' on the change in strokes.

My take is that:

A) He has tens of years experience at that.. don't know what shape the 'learning curve' on that was, but it might not be all that steep, up-front, given your prior experience.

and

B) Just as you have done on projects shared here on PM, he settles for 90-95% of the 'gain' to get the damned machine back into SERVICE.. without going anal for the last five or ten percent.. as some 'professionals' seem to have unlimited time and money to burn-up doing. Or claim to have always taken for themselves, 40 years and more.

Go for it. You've already sorted that unavoidable 'commercial necessity' time/money/usable BENEFIT limitation set. You'll do fine with this as well!

Pencil die-grinder, air-powered, BTW, and a good one, not HF-grade. Not a too-heavy-for-fine control AND hard to keep an eye on, angle-grinder.

"Critics" can buy their own damned Iron.

:)
 
Alright. Some progress. I switched blades and shortened to about an 8mm stroke. Then I kind of blasted the high regions and things started to spread out. But, then things kind of stalled.

The Biax manual says to let the blade float on the surface and just apply pressure where you want to scrape a point. I found this to be less than desirable. I ended up lifting the blade clear of the surface, which the manual goes out of its way to say is not required.

I can't seem to get a consistent print. I get tiny spots and big blotches. When the scraper blade is razor sharp it's really hard for me to control and wants to jump around. After about 10 minutes it calms down.

I'm guessing it's just about technique and controlling the Biax. I'll keep practicing. But, if anyone has any tips, I'm all ears.

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Yep. That's exactly what I do. You're on the right track in my estimation. Also, a smaller radius so you can break up the individual points in effort to get more distribution.

Ditto. This is above my pay grade, but anyway, I view the part from directly above, position the moving blade directly above the blue spot and "Dive bomb" the spot to cut it in half. Then cut the smaller spots in half the same way. Etc.
 
I have only used a Biax for a couple of days, at the recent Norway class so if someone more experienced disagree feel free to correct me.

From the first picture, I'd say it's still a bit early to stop roughing. Keep on roughing until the low areas around the slots have also become high points at least once or until you have measured that they are no lower than your scraping depth. I think scraping has a lot in common with other material removing processes like sanding/polishing or putting an edge on a very dull knife. It's generally faster to keep using the longer strokes or the coarsest grit until no improvement can be made without switching to shorter strokes or finer grit.

I don't think shorter strokes dictates faster movement. The distance between scrape marks is tied to the speed setting and not the stroke length, as long as your movement is the same. If anything I'd say shorter strokes are tied to slower movement given the same speed setting, as you will perhaps be using a shorter radius blade resulting in narrower marks.

I am waiting for a BL10 to arrive that I bought on ebay last week, so hopefully I'll be able to get more practice myself soon.
 
Lots of ways to multiply the finish bearing points if you figure in all the alternatives. The objective is to cut the middle out of each blue spot without overlap. This takes tight control of stock removal and consistent targeting.

There's many alternative techniques with more then a few that are efficient and accurate. After some experiments and mentoring I converges on what I call the "hover and drop" technique. I select a scraper radius about the same as a half dollar, set the stroke about 1/4" and the stroke rate about in the middle. Notice all the "abouts." Different results require juggling the variables. If you desire a deeper texture you'll want to use a scraper with a smaller radius; a denser pattern, a shorter stroke; etc. You have to play with it if your requirements are specific.

Hover and drop is not an efficient stock removal technique; it's a finishing technique not to be employed until I first get get overall coverage; The work first has to be first roughed and semi-finished to eliminate holidays, rolled off corners, and "railroad tracks".

The hover and drop technique I prefer consists of hovering the Biax just above (1/32") the work til you find a blue spot you wish to bisect, Then drop (actually briskly lower) the scraping edge on the spot allowing one or two strokes before lifting and moving on the the next. It goes "dot, dot. dot.." two to four dots per second with occasional pauses to look ahead and at the general results. I don't start at one end and work to the other. I select patches and mark them off with a Sharpie as I go here and there til I get coverage. If you don't move right along you get too deliberate and risk a couple too many cutting strokes, digging a hole instead of splitting a spot.

That's just my way. For me, hover and drop is a relatively quick and efficient method for finish scraping with a Biax. With it, I subdivide my bearing points to achieve my desired spot count, depth, and percent of bearing.

Your mileage may vary. Much depends on the work and the tools you have to work with.
 
If you would like to learn the proper way I will be teaching 2 classes for BIAX Germany the manufactures of the power scraper the last week of November and first week of December, 2017. They are furnishing brand new scrapers. It's nice to see Rich down under is using my Dive Bombing term and seeing a few of my students lending a hand in teaching! Rich
 
In the time you repeatedly swiveled the BIAX I’d have done it by hand. Dive bombing and everything can’t replace direct manual attack. Sorry one more time for an old-school fart to set things straight.
 
If you would like to learn the proper way I will be teaching 2 classes for BIAX Germany the manufactures of the power scraper the last week of November and first week of December, 2017. They are furnishing brand new scrapers. It's nice to see Rich down under is using my Dive Bombing term and seeing a few of my students lending a hand in teaching! Rich

Rich, does my "hover and drop" method parallel your "dive bomb" method (see above post #8)? Be funny if it didn't. I think I may have learned it from you and forgot where and when. I don't remember :"dive bomb". Maybe you didn't use the term in 1986.
 
In the time you repeatedly swiveled the BIAX I’d have done it by hand. Dive bombing and everything can’t replace direct manual attack. Sorry one more time for an old-school fart to set things straight.

I don't swivel in the finish cuts. I go at it from 45 degrees cutting both ways as in the roughing cuts. I've pinpoint scraped by hand and with a Biax. For the final 6 cuts or so (refining the bearing, multiplying the spot count, and controlling scraping depth) I'd estimate the Biax to be roughly twice as productive as hand picking and my neck and shoulders don't get tied into knots because of the need for precision control - one muscle group opposing another. Two hand passes picking in 36 spots per square inch on a big surface plate turns the upper half of my body to stone..

I'm mostly neutral on preference but the greater productivity and reduced pain and agony in finish scraping with the Biax and its ability to be dropped exactly on the spot for a single stroke is hard to forego.

So we're both right but I'm better looking.
 
Dive bombing and everything can’t replace direct manual attack. Sorry one more time for an old-school fart to set things straight.

All depends on how good you are at either. I forced myself to learn to use a Biax for finishing. I originally thought it not much chop for fine finishing until I spent the time to teach myself. Now I can dive bomb multiple targets a second and I get better results.
 
I don't swivel in the finish cuts. I go at it from 45 degrees cutting both ways as in the roughing cuts. I've pinpoint scraped by hand and with a Biax. For the final 6 cuts or so (refining the bearing, multiplying the spot count, and controlling scraping depth) I'd estimate the Biax to be roughly twice as productive as hand picking and my neck and shoulders don't get tied into knots because of the need for precision control - one muscle group opposing another. Two hand passes picking in 36 spots per square inch on a big surface plate turns the upper half of my body to stone..

I'm mostly neutral on preference but the greater productivity and reduced pain and agony in finish scraping with the Biax and its ability to be dropped exactly on the spot for a single stroke is hard to forego.

So we're both right but I'm better looking.

It's the "controlling scraping depth" where I am suspicious how good a Biax is for finish scraping.
 
As others have stated.

Shorten stroke and go to 60R then you can go down to 40R.

Pick every high spot.

Remember-individual scrap marks, individual scrape lines.

Use the dive bomb method as shown in the Biax Video Richard King did.

If you do not have one pick one up, it is well worth it.
 
I've got about 4 hours on a Biax and already I'd say its 2-3 times faster than hand scraping.

Im not knocking you ewlsey but you can handscrape a good bit faster than you show in the video.


Ive an old blue Biax but yet to have a real play. Have you got a speed control sorted?
 
Rich, does my "hover and drop" method parallel your "dive bomb" method (see above post #8)? Be funny if it didn't. I think I may have learned it from you and forgot where and when. I don't remember :"dive bomb". Maybe you didn't use the term in 1986.

I used to use the term Technique 40 that is described inside the DAPRA / BIAX manual until a class I did at Detroit Diesel Allison in Indy and in the 90's I think...been so many I can't recall exacly...8 diivisions of GM now. One of the students who learned to scrape like the old method Wes is using started to make sounds like he was dive bombing the spot and after that I started to call it dive bombing. The hover and drop term sounds good too. It was funny when I taught at Biax in Germany I used the Stuker Bomber sound as I showed the students. It was funny, they know immediately what I was saying...lol

I watched his You Tube and for the most part it was OK and that is the way "the old Farts used to do it" I did it like that when I was in my apprentice days and up until the late 70's when we finally learned how to scrape 40 PPI at Kurt Mfg when we scraped Moor Jig bores. I have to give the credit to one of my men as to shortening the length of stroke and grinding the blade to 40 R to my then foreman Craig Laurich who now has his own company Shop Services in Buhl MN. He now specializes in Bryant Center Hole Grinders..Used - Bryant 2" x 42" Center Hole Grinding Machine - YouTube He is one of the best scrapers I know. He as I learned to hand scrape. He learned to hand scrape at Staples Technical College in the late 80's and had never used a BIAX until he worked for me.

We did case studies at GM where they had records of how long it took Journeymen scrapers to hand scrape Heald ID grinders and boring machines. After they took the 40 hour class on Biax Power Scraping one man increased his productivity by 54% and another went up 76%.Plus I taught them my techniques I learned from my Dad ad learned on my own and Craig's techniques. At that time BIAX was coming out with the newer Green Matabo motor VS scrapers and they revolutionized scraping. Prior to that we used them to rough scrape and finish by hand as Don (Forrest you friend, forgot his PM name) talks about working with Sip. Before that we also had the blue scrapers like the one Wes shows that is totally obsolete for scraping 40 points unless you use a rheostat.

I could tweek his You tube, but I don't care to start a debate. I do know once he tried a newer BIAX he would never use those antique hand scrapers. I have had hundreds of "old Fart" stubborn students change their mind after they learned how to use a newer BIAX. I have had several students scrape 60 PPI with them and also some who still prefer to hand scrape. To each his/her own. Stefan in Germany (PM member used a Renz Power scraper and from his recent You Tube and writing here admits he learned to power scrape better then before. I believe he learned from Nick Mueller. Many hobbyists prefer to do it the old way as they have a lot of times on their hands or can't afford BIAX Scrapers, but as a professional rebuilder trying to make money we had to learn a faster and better way. The BIAX has revolutionized the scraping world, as has Turcite, Moglice and Canode. The last class I just finished in Georgia the students said since I started to teach the hobby classes the price of BIAX's and Glendo's have doubled on EBAY...lol...Rich
 








 
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