Surface grinder attachment tips

[Signalprick]

Quick update from earlier. I pulled a blade out of the bin. This blade was rough profiled, surface ground with a 180 ceramic trizact, nick cut, stamped and heat treated. Here are my measurements. From here I will do final profile and knock the scale off with a 400 grit ceramic trizact on the SGA. I'll shoot for no more than .002 per side from here. Not a bad tolerance though. I'd say my process is decent. FYI I am using an Ameribrade SGA.

 

[Hubert S.]

Quick update from earlier. I pulled a blade out of the bin. This blade was rough profiled, surface ground with a 180 ceramic trizact, nick cut, stamped and heat treated. Here are my measurements. From here I will do final profile and knock the scale off with a 400 grit ceramic trizact on the SGA. I'll shoot for no more than .002 per side from here. Not a bad tolerance though. I'd say my process is decent. FYI I am using an Ameribrade SGA.

View attachment 1844119

That is really impressive, I don't even have a micrometer that can measure down to that level.

Are you using the 3M 953FA belts? I think my trizact belts are aluminum oxide, 347FC if I remember right.

 

[Signalprick]

That is really impressive, I don't even have a micrometer that can measure down to that level.

Are you using the 3M 953FA belts? I think my trizact belts are aluminum oxide, 347FC if I remember right.

Thank you. Correct 953fa trizacts. It took me a bit to get those results. There is def. a learning curve to using a SGA.

 

[Natlek]

I remember seeing a video where someone removed the grit from the area where the belt is spliced for that reason. I think it may have been in one of Travis Wuertz's videos.

Do you mean parallel lines going across the blade or along the length? I had a line pattern going across the blade before I trued up my contact wheel, now it is almost gone.

Yes , parallel lines across the blade . My contact wheel is trued as it can be , first we make shaft for wheel on CNC and then put wheel on that shaft without removing shaft from CNC .
Yes , almost gone lines is what I am talking about .I think that they are from joint on belt and I need to make extremely light pass so they disappear....
Reason you get rolls over edges with rubber contact wheel is because rubber compress no mater how hard it is .In first contact with steel it is not compressed , that fraction of time is when belt remove more steel there and then it is under constant pressure / compressed/ and belt remove steel even . Same with holes , rubber expand over hole ...................if I have well explained what I think ?

 

[Hubert S.]

Yes , parallel lines across the blade . My contact wheel is trued as it can be , first we make shaft for wheel on CNC and then put wheel on that shaft without removing shaft from CNC .
Yes , almost gone lines is what I am talking about .I think that they are from joint on belt and I need to make extremely light pass so they disappear....
Reason you get rolls over edges with rubber contact wheel is because rubber compress no mater how hard it is .In first contact with steel it is not compressed , that fraction of time is when belt remove more steel there and then it is under constant pressure / compressed/ and belt remove steel even . Same with holes , rubber expand over hole ...................if I have well explained what I think ?

Yes, I got it. It would make sense that the thicker belt splice has the same effect as a wheel that is slightly out of round. I have to take some more measurements now that I have trued up my wheel, the surface looks a lot flatter without the parallel lines. Signalprick 's results are really impressive, and I think the Ameribrade SGA he uses comes with a high durometer rubber wheel. Maybe really light passes and the right belt is all it takes. I have an aluminum wheel that is crowned for a new tracking mechanism I plan on building at some point, but I might turn it flat and put it on the SGA to see how big a difference it makes.

 

[Natlek]

One more thing , I don t think that serrated contact wheel is best choice for this .Solid rubber would be my choice if I use rubber wheel .

 

[HSC ///]

No , reason is rubber on wheel ,no mater how hard it is it is rubber and will compress every time . I use aluminium wheel and have no problem with rounding .With Al wheel problem is part where belt is glued .If you really at end want nice clean finish you need to make extremely light pass to catch just that part of belt where it s glued with that sticker?...........
if you see parallel lines across the blade they are from sticker because the belt is thicker there .......I use 100 grit ceramic belt for finish and simple i can fell that problem , even on 32 m/s belt speed .

I have an aluminum wheel on the SGA I built. Works pretty good for keeping a flat surface.

I have a surface grinder attachment here on my grinder in France, it's new to me,
highly productive but I get rounding which will be unacceptable for folders.

I'm going to get an aluminum wheel made, anything specific about this I should know before I get it made?

thanks

 

[N.W. Gean]

I have a surface grinder attachment here on my grinder in France, it's new to me,
highly productive but I get rounding which will be unacceptable for folders.

I'm going to get an aluminum wheel made, anything specific about this I should know before I get it made?

thanks

The issue I have with my aluminum wheel is that it makes kind of a washboard effect of divots across the blade. Like Natlek says, I think taking lighter passes and taking the time to remove the belt seam would fix that.

Otherwise, it's much better than the 75 duro rubber wheel I was using. The edges are nice and flat

 

[Scaniaman]

I have a surface grinder attachment here on my grinder in France, it's new to me,
highly productive but I get rounding which will be unacceptable for folders.

I'm going to get an aluminum wheel made, anything specific about this I should know before I get it made?

thanks

Would it not be a bit complicated changing between the aluminium wheel and the rubber one, since that is mounted as the drive wheel on that grinder? Maybe a solid/smooth 90 Shore rubber wheel could be a good compromise? L Paladin has them for around 60 euros with bearings installed.

 

[HSC ///]

Would it not be a bit complicated changing between the aluminium wheel and the rubber one, since that is mounted as the drive wheel on that grinder? Maybe a solid/smooth 90 Shore rubber wheel could be a good compromise? L Paladin has them for around 60 euros with bearings installed.

I don’t know, I’ll ask Tobin

 

[Ken H>]

This is from my homemade SGA using a 90 duro poly wheel. I take a small <.001 pass each time for final passes, perhaps 400 grit belt?
Here's what I got a few year back.
Tang:

Middle

Tip

 

[HSC ///]

This is from my homemade SGA using a 90 duro poly wheel. I take a small <.001 pass each time for final passes, perhaps 400 grit belt?
Here's what I got a few year back.
Tang:

Middle

Tip

What is a poly wheel? Polyurethane?

 

[HSC ///]

Would it not be a bit complicated changing between the aluminium wheel and the rubber one, since that is mounted as the drive wheel on that grinder? Maybe a solid/smooth 90 Shore rubber wheel could be a good compromise? L Paladin has them for around 60 euros with bearings installed.

The answer is, no it’s not complicated, it’s just three screws easily accessible to loosen and remove

 

[Ken H>]

What is a poly wheel? Polyurethane?

Yep, just the cheap Polyurethane wheels ordered from China

 

[DanF]

If you use precision ground billets do you “need” a SGA?

 

[HSC ///]

If you use precision ground billets do you “need” a SGA?

Maybe not. But I don’t want to be limited to precision ground material.
A surface grinder attachment allows you to do distal tapers, this is helpful on a long 9-10” kitchen knife. I can taper full tangs. And I forge half the time so I can work with uneven surfaces on a the SGA.

As far as folders, I’d rather be able to control the thickness I want