Author Topic: Show us your scraper sharpening devices  (Read 1677 times)

Offline Mover

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Show us your scraper sharpening devices
« on: January 02, 2018, 03:09:45 AM »
Im trying to come up with ideas for a sharpening / lapping station for carbide scraper blades. So what are you useing?


Offline Graham Stabler

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Re: Show us your scraper sharpening devices
« Reply #1 on: January 02, 2018, 03:27:04 AM »
I bought a record wet stone sharpener with the idea of mounting a diamond lapping disc on the side of one of the wheels, I didn't like the quality for the price so it is going back to the supplier, I might get a Triton instead or scratch build something.

I really like this concept: https://www.woodsmithplans.com/plan/drill-press-sharpening-station/

The drill press provides the drive and doesn't have ways to worry about contaminating.

Otherwise I am thinking of home brewing something, possibly using the drive mechanism of the Record grinder (see attached) and maybe a fridge fan motor:

Fridge fan motor on ebay

Cheers,

Graham



Offline Mover

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Re: Show us your scraper sharpening devices
« Reply #2 on: January 02, 2018, 03:52:02 AM »
Scratch built is looking more and more likely as there doesnt seem to be much available off the shelf.

Offline mattinker

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Re: Show us your scraper sharpening devices
« Reply #3 on: January 02, 2018, 07:18:26 AM »
I've just bought this solution to to the problem. After the Richard King class where I used Pete's low speed grinder, I decided that it was a better way to go.I had previously bought a cheap bench grinder, to make a Stephan Gotteswinter type 3000grit, 2450 rpm grinder. I made a 8mm steel plate as a backing plate, but the shaft was so bad that it's run-out made it unusable! So, it's a cheap low speed "wet" grinder, with a standard speed other end that I will probably put a green wheel on. I used the original spacers to mount the 3000 grit disk just to try it. The shaft is 12mm, whereas the disk and spacer and disk are 12.7mm (1/2") The 0.7mm out of round poses no problems!!

Offline RotarySMP

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Re: Show us your scraper sharpening devices
« Reply #4 on: January 03, 2018, 09:52:29 AM »
To grind the -5 rake into my blades, I just set up a temporary rest at that angle on the Clarkson, and use a diamond wheel to free hand the radius.

My scraper is an old Coborn 1817 Type 1. Not sure how old it is, but it has the power unit separate from the handpiece, with the power transmitted by a flex shaft. The stroke is adjustable with just a large screw driver through the hole in the hand peice. The Coborn is pretty nice to use. I haven't used a Biax, but the weight is about the same as my friends Biax (gets heavy fast). The nice thing is that the Coborn is so quiet.

One advantage of that remote motor, is that there is a cast iron lapping plate moounted on it for touching up the blades. I got some fine diamond lapping paste from Ebay. There is also a radius jig, which is adustable for cutting rake angle but unfortunately the radius is built into the ball bearing tool holder. To lap a different radius, you would need a different tool holder assembly.

Since the only tool holder I have is a very large radius (about 150mm / 6"), so I don't use it. I'll remove that jig, and make up a fixed -5 jig which I can switch between the Clarkson for grinding, and the Corborn for lapping and touching up.
Mark

Offline PekkaNF

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Re: Show us your scraper sharpening devices
« Reply #5 on: January 03, 2018, 02:37:13 PM »
Well, I have semifinished contraption. I have multiple width scrapers, made jig for each one. There is a cast iron disc that can be covered with different grit thin diamond disc.

It is not finished yet. Mainly it is missing hold down magnets for radius plinth. That has some holes for three different radiuses.

Pekka

Offline Graham Stabler

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Re: Show us your scraper sharpening devices
« Reply #6 on: January 26, 2018, 04:56:41 AM »

Offline Pete.

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Re: Show us your scraper sharpening devices
« Reply #7 on: January 26, 2018, 07:54:40 AM »
That's been advertised quite a lot but never sold. I think the main reason is it's 415v.

Offline Pete.

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Re: Show us your scraper sharpening devices
« Reply #8 on: January 30, 2018, 06:36:41 PM »
 If you were at the class you will recognise this:

http://r.ebay.com/xmvdUv

I have one spare stand left so if someone fancies buying it for lapping their scrapers they can have the stand for the cost of postage.

Offline awemawson

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Re: Show us your scraper sharpening devices
« Reply #9 on: January 31, 2018, 02:58:28 AM »
I can cut more stands out on the CNC Plasma table if the demand is overwhelming Pete !
Andrew Mawson
East Sussex

Offline Pete.

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Re: Show us your scraper sharpening devices
« Reply #10 on: February 05, 2018, 03:30:00 PM »
Who is going to be the first to try one of these?

https://www.lidl.co.uk/en/Non-Food-Offers.htm?articleId=10590

Offline mattinker

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Re: Show us your scraper sharpening devices
« Reply #11 on: February 05, 2018, 03:56:41 PM »
You'd need 3000 grit disks at that speed!

Cheers, Matthew

Offline Pete.

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Re: Show us your scraper sharpening devices
« Reply #12 on: February 05, 2018, 04:03:37 PM »
Variable speed Matt. Doesn't say the minimum rpm though.

Offline RotarySMP

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Re: Show us your scraper sharpening devices
« Reply #13 on: April 03, 2018, 03:06:02 AM »
On Friday a mate dropped of the laser cut steel bits to make the scraper honing rest.

I tried furnace brazing them in my casting furnace. Not the prettiest result, as I put the base in the cold oven, but the brazing rod didn't melt till over 900C. Despite painting the steel with a coating to prevent oxidation, it was in so long that it got rather heavily oxidised.

The top part went into the preheated oven, and went much faster. The oxidation on it was much reduced. Unfortunately, once it was out I found a bit of braze which hadn't melted, but it will hold.

Soaked them in dilute HCl for about a half hour to get most of the oxidation off them, and will probably sand blast them once finished. The look pitted in the last photos, but that is just the water and WD-40 on the surface, as I sprayed them immediately after neutralizing the acid and washing.

Still need to make the adjustable radius swinging scraper holder widget to go on top of it, and some shorter bolts to lock the angle.
Mark

Offline awemawson

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Re: Show us your scraper sharpening devices
« Reply #14 on: April 03, 2018, 04:17:46 AM »
Looks nice and solid, and should clean up a treat  :thumbup:
Andrew Mawson
East Sussex

Offline RotarySMP

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Re: Show us your scraper sharpening devices
« Reply #15 on: April 05, 2018, 11:20:48 AM »
Thanks. Wonder how many years till I finish this job :)
Mark