Gadget for grinding gravers with rounded shapes from blanks

[rweigel]

Hello,
I made a simple gadget that allows to grind gravers with rounded shapes from blanks. Up to four radial stops permit to set start und stop angles. A round bottom graver would require two stops, an onglette or oval graver reqires four stops. The onglette in the pictures has got 120° tip angle, and 60° at the top. It was the first attempt with the new tool.

I put the heel onto the onglette graver with a second gadget I made. I might post pictures of it later. I have overdone the heel width at the top of the graver a bit, which is of no consequence for it‘s function.

Cheers

Ralf

 

[monk]

looks spiffy to me. perhaps you should post all this on the classified section of the forum.

 

[rweigel]

Hi Monk, can't post there, have not got the right membership...

 

[FANCYGUN]

I always found that just free handing the heel on an onglette with a simple twist of the wrist was the fastest easiest way to do that. Just lift up and twist. repeat for the other side by twisting the other way

 

[Webb]

For high precision I prefer gadgets. Rweigel

 

[papart1]

what motor are you using please?

 

[rweigel]

Hi Papart,

it is a 12V DC Motor from Bühler, also built by Johnson Electric. They where available at 1 Euro / pcs. at an surplus electronic shop. Years later I found where they are actually build in: pumps for parking brakes of Diesel cars, e.g. BMW. They are very quiet, have a high torque and very precise bearings. I use them also with flexible shafts. With a PWM power controller, I could rotate as slow as 60 rpm and up to several thousand rpm.

 

[papart1]

thank you sir

 

[rweigel]

There are now BLDC Motors for lawn mowers ect. which could run at low speed and full torque with a suitable controller. I was tempted to use one of those for the next minihone I‘m going to build, but with about 20 of the DC motors still in my stock I will stick to the Johnson motor.