Shop Made Power Flaker

zipfactor · May 10, 2016

Since I couldn't justify spending $1000+ on a power flaker, I decided to whip one up myself. I used a sawzall, gutted the reciprocating mechanism, and made a clutch with an eccentric cam / scotch yoke mechanism. I re-purposed the existing reciprocating shaft and was able to use the existing housing with exception of a small cutout. Here's a few pics...

And the result (used aluminum as it's all I have around at the moment)

Hope you guys find this interesting. I hadn't really seen any type of shop made power flakers out there and thought I'd share what I put together. Enjoy!

-Ben

RC99 · May 10, 2016

That looks very good but I cannot see the forward/backwards reciprocation motion that the power flaker does that is created by a swash plate with a bearing running against it.

zipfactor · May 10, 2016

Another picture showing the complete assembled flaker

zipfactor · May 10, 2016

Here's a few more pics that may help show what is going on. I'll try to post a video soon to show it working.

Cam / Yoke mechanism (top):

Cam / Yoke mechanism (side):

The flaker works the more or less the same as the Biax, there is no motion until you push against the work piece, then the clutch engages and begins cutting.

TGTool · May 10, 2016

So the scotch yoke provides a rocking motion of the shaft (and cutting tool) instead of the fore and aft reciprocation of the original? And the motor runs but doesn't operate the shaft until there is a backwards pressure to engage the clutch? Interesting.

zipfactor · May 10, 2016

TGTool said:
So the scotch yoke provides a rocking motion of the shaft (and cutting tool) instead of the fore and aft reciprocation of the original? And the motor runs but doesn't operate the shaft until there is a backwards pressure to engage the clutch? Interesting.

Yeah, that's exactly right. There is a small disc spring in between the clutch faces that keeps the mechanism disengaged until backwards pressure is applied (pushing forward). I've never taken a power flaker apart but I assume it works similarly.

RC99 · May 10, 2016

Internal pics of a Biax flaker. I cannot see the swash plate in your design. I think that is why you are not getting the proper crescents. I am happy to pull the front off my 8E and measure it up for you. It is only three nuts. The crescent height is dependant on the radius on the tool, the crescent length is not adjustable as it is fixed.

Int he picture of the two parts, you can see a bearing cage, but no balls or outer race. This was how mine arrived, but it wass only a $4 bearing to fix it. It made similar parts to yours as there was no forward/back motion.

zipfactor · May 11, 2016

RC99 said:
Internal pics of a Biax flaker. I cannot see the swash plate in your design. I think that is why you are not getting the proper crescents. I am happy to pull the front off my 8E and measure it up for you. It is only three nuts. The crescent height is dependant on the radius on the tool, the crescent length is not adjustable as it is fixed.

Int he picture of the two parts, you can see a bearing cage, but no balls or outer race. This was how mine arrived, but it wass only a $4 bearing to fix it. It made similar parts to yours as there was no forward/back motion.

View attachment 171058 View attachment 171059

Thanks for the pics. I didnt realize there was a swashplate that gave a slight back and forth reciprocating motion in addition to the rotary oscillation. Looks like a bit of design oversight! I'll have to rework a few parts to incorporate that motion. Thanks for the pics!

One question: I'm assuming the swash action is "timed" with the peak of the eccentricity so that when the blade is rotated at its maximum position, its at its maximum swash displacement. Is this true?

EDIT: One additional question, what is the diameter of the eccentric pin in the image? I'm trying to get an idea on the ramp profile for the swash action.

RC99 · May 12, 2016

I went and took some dimensions of mine to help you out. I cannot see any reason to try to reinvent the wheel.

I am not sure if the image I have drawn will be helpful but I understand it

Essentially the output shaft moves backwards and forwards 2mm and oscillates 4 degrees either side of zero position. The crank pin is timed so that when it is at top dead centre the swash plate is forward the full 2mm.

The output shaft to crank shaft centre to centre distance is 13.5mm which gives the eight degrees total oscillation.

Only thing I am not sure of is which way the drive shaft rotates. I will go check that out in due course.

It is a Swiss/German machine so that is why the measurements came out at whole mm dimensions.

zipfactor · May 12, 2016

RC99 said:
I went and took some dimensions of mine to help you out. I cannot see any reason to try to reinvent the wheel.

I am not sure if the image I have drawn will be helpful but I understand it

Essentially the output shaft moves backwards and forwards 2mm and oscillates 4 degrees either side of zero position. The crank pin is timed so that when it is at top dead centre the swash plate is forward the full 2mm.

The output shaft to crank shaft centre to centre distance is 13.5mm which gives the eight degrees total oscillation.

Only thing I am not sure of is which way the drive shaft rotates. I will go check that out in due course.

It is a Swiss/German machine so that is why the measurements came out at whole mm dimensions.

View attachment 171148

Wow! Thanks a lot, the drawing is great!

My setup does have the 2mm rotary "stroke", so I'll just add a simple swash plate collar around the existing eccentric cam portion, along with a bearing at the bottom of the slotted block and I should be in business.

Looks like I owe you a pint (do Aussie's call it a pint?)! Thanks much RC!

jhovel · May 12, 2016

Very interesting! I'm planning on converting a jigsaw that has a mechanism for blade foreward and backward motion (most do). I intend to use it's vertical motion to rock the blade spindle/guide side to side and its for-aft motion for the blade fore-aft. Thanks for the measurements RC!
As a point of interest: I don't believe the Renz flaker we have both used has that foreward - backward motion. I'm prettycertain it ONLY rocks the blade.

zipfactor · May 12, 2016

deleted double post.

pbrubaker · May 12, 2016

Has anyone put together a set of plans to build scrapers/flakers from commonly available surplus motors? Like say NEMA frame AC speed control motors? I know there have been a number of modifications to existing tools, but I haven't seen a from scratch design (albeit I'm pretty new here.)

I'd need some help with dimensions of the mechanisms but I'd be happy to model them up and distribute the drawings. I can't imagine that the patents for these devices are still current.

zipfactor · May 12, 2016

pbrubaker said:
Has anyone put together a set of plans to build scrapers/flakers from commonly available surplus motors? Like say NEMA frame AC speed control motors? I know there have been a number of modifications to existing tools, but I haven't seen a from scratch design (albeit I'm pretty new here.)

I'd need some help with dimensions of the mechanisms but I'd be happy to model them up and distribute the drawings. I can't imagine that the patents for these devices are still current.

I thought of going that route, but by the time you factor in the raw material costs, component costs such as bearings, and machining time, you'd be better off buying a used Biax.

No offense meant to others that have made power scrapers, but the designs are rough. Using a sawzall's mechanics for power scraping is like using a jackhammer to wipe off a kitchen counter. The vibrations are harsh after using the tool for more than a few minutes. Better would be to copy the gold standard design (i.e. Biax), and apply those mechanics to a commonly-available tool. This approach also saves a lot of time and money. Also, your using the manufactured tool's economies of scale instead of your economies of scale (which is nonexistent).

DanLinsch · May 13, 2016

zipfactor said:
I thought of going that route, but by the time you factor in the raw material costs, component costs such as bearings, and machining time, you'd be better off buying a used Biax.

No offense meant to others that have made power scrapers, but the designs are rough. Using a sawzall's mechanics for power scraping is like using a jackhammer to wipe off a kitchen counter. The vibrations are harsh after using the tool for more than a few minutes. Better would be to copy the gold standard design (i.e. Biax), and apply those mechanics to a commonly-available tool. This approach also saves a lot of time and money. Also, your using the manufactured tool's economies of scale instead of your economies of scale (which is nonexistent).

I agree with you on this. Also, I'm not sure making an adjustable length stroke unit starting with a sawzall would be a trivial matter.

Dan

PDW · May 13, 2016

DanLinsch said:
I agree with you on this. Also, I'm not sure making an adjustable length stroke unit starting with a sawzall would be a trivial matter.

Dan

It's been done by a few people. I had a crack at it myself. Partial success, PITA though.

I bought an old Biax and am much happier.

PDW

Zahnrad Kopf · May 13, 2016

DanLinsch said:
I agree with you on this. Also, I'm not sure making an adjustable length stroke unit starting with a sawzall would be a trivial matter.
Dan

Actually, it is almost trivial. The biggest issue with all of the offerings is that the front bearing area ( almost always a bushing ) offers little if any precision fitment and prevention against wobble/deflection.

I am very intimate with the inner workings of sawzalls and their mechanisms. I had considered a conversion myself as some models offer not only adjustable stroke, but also conversion between linear and orbital stroke. The bottom line is that I would rather buy a Biax or Renz than spend the time and effort to do the conversion and am on the hunt for one now in effort to finish up my Monarch.

Monarchist · May 13, 2016

Zahnrad Kopf said:
The bottom line is that I would rather buy a Biax or Renz than spend the time and effort to do the conversion and am on the hunt for one now in effort to finish up my Monarch.

Whilst I am still in denial as to getting far enough along to NEED one... and slowly losing that battle..

What this community needs is a stone-soup style rental program... ELSE all the needfuls get snapped up, and don't come back into the pool/market 'til some Pilgrim or another ups and retires 'fully' (if ever even this lot DO that..). Or dies.

Bill

bmikkalson · May 13, 2016

Awesome!! Love it!

rotarySMP · May 14, 2016

THis is pretty cool. There are a few good illustrated posts on converting saber saws to scrapers, but it looks like you are the first to do a flaker.

Just getting a Biax is a great idea, but at least here in europe, they go for big bucks even used and only rarely come up for sale. For a tool which is only used for a single project, it is probably okay to buy one, use it, and the sell it to recoup the money. In practice, I know I wouldn't sell one again. great that guys like Ben are showing alternatives.

Mark

Shop Made Power Flaker

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