Problems toward the Spine.

E

EmbraceTheEdge

Joined
Apr 26, 2014
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I seem to be running into the same problem over and over as my bevel gets closer to the spine. It starts out well, to my eye, but the higher I go, it starts to become uneven and gets to high too fast.

Below are some pictures with sharpie marks left on so you can see each side more clearly. It this just my angle?

Sorry about the links (hopefully they work), I guess I'm supposed to pay to insert pics now.






The steel is O1. It's 2" wide and 3/16" thick. Blade is about 5-1/4" long and the overall length is bout 10-3/4". I'm using a JET 2x42" grinder and used a 40 and 60 grit belt to get it this far. I'm in my early 40's, have been doing this for a few months and love it! I work in an office so I'm not a natural hands on tool guy by nature. Oh and I use a tool rest.

I don't post much but I'm always around.

All critiques and suggestions are welcome. Thanks in advance.
 
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You need a Photobucket account or something similar. You can get a free account. Then upload your pics there. Next to the pictures in your library there will be various ways to link your picture. Click on the link shown and then paste it into your post. Easy Peasy.




Looks to me like the problem is just lack of practice. The more you do it the better feel you develop. Specifically the problem seems to be mechanics and consistency. On the side where your bevel goes high at the plunge line you are applying more pressure there than other areas of the bevel. This can be with the bevel flat to the belt but applying too much pressure with your hand or because you have the blade angled to the belt a bit which causes more pressure in that spot. Same on the other side. High spots on the bevel are areas that are getting more pressure than other areas.

Pay close attention to your body mechanics. Have your grinder set up at a height that is comfortable. You shouldn't be hunched over. You shouldn't have your hands up at your chest. Your hands should be about belly height. Stand with your feet roughly shoulder width apart. lock your elbows at your sides. With your knees slightly bent use your legs to shuttle your upper body back and forth. It helps to slow down a bit as your bevel gets towards the spine. Use less pressure and pay close attention to pulling the blade straight across the belt. Lift the tip off the belt before it runs off the edge of the belt. Draw a line on the blade to use as a target or reference line on both sides of the blade if it helps. This way, you have a visual of where you need to remove material and where to be more careful. Using the work table is ok. I think you have better freedom of movement and develop a better sense of feel for how and where to apply pressure when grinding freehand. But that is just my personal preference.

Time and practice is the remedy. And the usual advice applies here. Practice on scrap steel if you don't want to take chances with a blade into which you've put a lot of effort. Keep us updated with your progress.
 
Thanks for the reply iMarc. I am using image shack. They changed everything since I had been there last, plus it was late last night, so I couldn't figure it out. I looked again to today and got it.

EDIT: It looks as if Image Shack only allows thumbnail size for free now. I have to pay in order to get them bigger. Lame. I'll look into photo bucket. EDIT: And done.

I read your post and checked out my grinder height. I'm tall so it's low. The bottom of the platen is right about belt height. I'll try and figure out how to raise it. As you can see in the picture below, the flat platen is small so I don't have a lot of area to work with.



Here's the thing with the work table. There is also a gap at the bottom that I'm afraid my knife or fingers will get sucked in to.



It's kind of hard to see but that gap is fairly large. I'm willing to give it a shot, is just scares me a little bit. haha

Thanks again for all of your advice. I'll pay more attention to my mechanics.
 
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I'd be a little concerned about that gap too. Can the work table be removed completely if you wanted to? If you can't Id try to make a better work table using a piece of wide angle iron and a piece of mild steel or something. Make it adjustable so you can set it in position close to the belt with maybe a 1/16" gap. And have the table overlap the platen, not sit below it. Looking at the "from above" angle picture it appears that your work table, what there is of it, is not parallel to the platen. if you align your blade with the table and try to grind you will likely get the kind of results you showed earlier.
 
Whoops! Sorry, I wasn't clear, or I'm not understanding. The picture you see is without the tool rest. With the tool rest in place there isn't a gap. I could free hand with the tool rest in place I suppose but the platen is so small there isn't a ton of room. With the tool rest off, as you can see, there's a huge gap that my fingers are afraid of.

Here's a side Pic with the tool rest off:


With it on. It's sits a little higher then what I'm holding up.


When the tool rest is on I don't see that bottom gap.

I'll try and free hand with the tool rest on to see how it goes. I'm pretty sure I'll have to ben the plate forward (toward the belt) as it leans back a little.

Thanks again for your replies i4Marc. I really appreciate it.
 
That's a monster of a tool rest. You might be able to make a thinner, lower profile tool rest... or just a guard to block the gap.
You could certainly improve the platen. It could be as simple as attaching a longer piece of precision ground and hardened tool steel to the existing platen, or mild steel with a ceramic plate. That would give more working area but also smoother and more consistant grinds.
I know that adding a ceramic tile to my 2x42 Craftsman really improved my bevels.
 
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