Thread: DIY power scraper

Stu, I imagine you had a look at this thread: Power scraping. Anyone tried to convert a Makita HK0500 for metal? - Practical Machinist - Largest Manufacturing Technology Forum on the Web just making sure....
Here is a close-up of my blade mount adapter (sorry about fuzzy - taken with phone):

Hi Stuart, Joe,

Interesting idea, I don't see why it won't work, that's a flash of genius to add a spacer..

Instead of a dovetail slide, could you use the extra height to mount the drive pin on an eccentric, so as you rotate the mount the distance between the center and the pin would vary to adjust the stroke. Might be possible to come up with a shape that maintains the balance as it rotates.

Regards
Ray

Hi Joe,
I have seen that thread but I'm not sure I have as much thickness to play with, I'd be worried that the slide wouldnt have enough meat to support the shortened pin, but it seems to be working for him. I'll have another look. I'd like to be able to do the adjusting and locking from the side. Thanks for the picture.

Hi Ray,
Thanks
MkI might be something like you discribe. I've realised the balance might not be as much of an issue as I thought as I will be adding a fair amount of weight with the blade mount adapter so that will help even things out.

Stuart

One important thing is you have to keep the blade stiff.. When you look at Phil's Renz it uses a rectangular guide to keep the blade motion back and forth with no sideways or twisting movement...

Biax uses two hardened steel guides on a taper (for adjustment) either side of the blade to keep the blade running straight and true... http://www.practicalmachinist.com/vb...e-pads-205519/

Hi RC,
That could be a little hard to do as the plates that stop the twisting are inside, but I'll keep an eye on it.

Got the spacer made today.(I'll leave it as is on the outside as it might come in handy if more support is needed)
The "simple little job" of extending the slot in the body ended up taking a while as I had to do it with the motors rotate in the way.

I'll have to pick up some M5 bolts the right length before I can test it.

Stuart

Hi Stuart,
I am watching your progress with interest.
I am not sure if you have already seen it, but there is one somewhere on the net that the guy had a dovetail piece in it for stroke adjustment. I can't remember if it worked out or not.

Dave

Hi Stuart,

Looks promising, I can cook up ( heat treat) some M2 (HSS) for the final version when the design is finalized.

Regards
Ray

Dave,
did you see the link in message #2?

Originally Posted by jhovel

Dave,
did you see the link in message #2?

Hi,
I never followed that link, but thats the exact one I was talking about.
I remember reading it when it was posted, though I didn't realise it was that long ago, LOL

Dave

Hi Guys,
As I dont have the bolts to finish it today I think I might skip MkI and go straight to MKII. This is the current thinking, with a M6 grub screw from one end and a M5 from the other.

Thanks Ray, you've got me thinking more about the plate RC pointed out. Although it might be a bit of a gold tooth on a pig

Stuart

HI Stuart,

I was just thinking, that if yourself and Joe were doing the same modifications, I could provide a small contribution of M2, Joe has already got a good supply of M2 here, and it would be a perfect application for a few small pieces.

Hardened precision ground slides are always nice.

Regards
Ray

Originally Posted by Stustoys

Hi Guys,
.....This is the current thinking, with a M6 grub screw from one end and a M5 from the other.
....Stuart

Stu,
I'm not sure if I understand the sketch. What's the rebated slot for? Does the T-shaped slide run in it? Would that mean you will have to cut a T-slot throught the spindle?
Where will the two screws go you mention? Is one of them a kind of leadscrew and the other a locking screw?
Can you take a photo of the "shuttle" (the U-shaped thingi the needle roller beating runs in) and the mating surface on the cover?
I had to fill the back of my shuttle with bronze to remove most of the play between it and the cover to stop the tool rocking. I may yet have to come up with a more rigid "rubbing block" in the cover...

Hi Joe,
The T-shaped slide does run in the rebated slot.
The reason I added the spacer into the body was so I could add these pasts onto whats there(the pictures of what I have done today should help).
The two screws, one in come from each end of the rebated slot and press against the T-shaped slide.(why two sizes you ask? Because you wont be able to see what is going on, so turning the M6 grub screw clockwise will increase the stroke, anti clockwise will shorten it.(assuming I get them on the correct end lol)
I think I'd have to glue some bronze to the shuttle on mine, but I'm thinking about adding plates externally. I think it will be used up side down. (I cant turn the handle on mine either but at least it has a trigger lock)

I'd be lost without the DRO on my mill

Stuart

p.s. the little drill marks in the thrid last picture are just to help set it up vertically when I am drilling the holes for the grub screws.

Originally Posted by Stustoys

Hi Joe,
.....I think I'd have to glue some bronze to the shuttle on mine, but I'm thinking about adding plates externally......
Stuart

Thanks for the explanation and the photos. Now all is clear!
Great work! You are really getting into it now!
The shuttle and guides are the same as mine. I think milling the two narrow diecast guide ribs off and replaing them with bolted in much wider bronze or cast iron stips would work well. Wide enough to just clear the reciprocating rod, and wide enough to rupport the shuttle all the way to the little 'wingtip' ends. Running in grease would keep the wear in check.
Mine has already developed notable play again after using it for maybe 12 hours or so since my build-up mod.
Joe