How do you flatten your blade without a surface grinder?

LARRYZ10

LARRYZ10

Joined
Feb 6, 2010
Messages
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I do not have a surface grinder and have no space for one so I have been flattening my blades with a combination of 4x36 sander to start, a flat platen with chiller to pretty flat and smooth, and a 9 inch disc sander to smooth and flat. Then I grind and drill and heat treat and go back to the disc with several grits. Lastly I use a Lucite block with fine papers before a buffing.

What do the rest of you do to get a nice flat ricasso and area above the grind? I take a lot of time doing this and would like some suggestions to speed up the process just a touch. I am currently looking at the Travis Wuertz attachment for a KMG grinder. Thanks, Larry
 
to have a single flat surface, a disk sander would handle the issue pretty well...problem is when you have to get 2 plane surfaces and parallel.
Without a surface grinder (or a TW like attachment) it isn't impossible, but it will require measurements and lot of precision hand work.
best option is a granite plate (or other true plane) and a dial or at least a micrometer if we are talking about little surface like the ricasso.
 
I approach the disk very slowly to where it's barley touching(won't grind)at that point
the steel will usually settle in flat.I also use a large magnet to hold the steel and
sometimes use a bubble level to help keep me flat on approach.It can be slow tho.
Medium speed using 9'' vari.
 
I have a surface grinder but I dislike using it (miserable contraption). For fixed blades that don't need to be perfectly flat I do it lengthwise on a flat platen. I remove the top wheel and angle the platen back, stand to the side and lay it down flat lengthwise.

The platen needs to be very flat, obviously, but in my mind this is similar to using paper and a surface plate. Leading and trailing edges can still be rounded because the belt (or paper) can bunch up, so you want to use sharp belts, high tension and moderate pressure. It's better to do it before you've finished your profile and finished grinding your bevels.

I don't know if this is adequate for what you're going for, but it works for me.
 
I use a 3/4x5 magnet to hold the blade and them hold it against my ceramic platen. Make sure to cover the magnet face with tape and blow it off when switching sides or you will scratch the side you just completed.
 
Nathan the Machinist said:
I have a surface grinder but I dislike using it (miserable contraption). For fixed blades that don't need to be perfectly flat I do it lengthwise on a flat platen. I remove the top wheel and angle the platen back, stand to the side and lay it down flat lengthwise.

The platen needs to be very flat, obviously, but in my mind this is similar to using paper and a surface plate. Leading and trailing edges can still be rounded because the belt (or paper) can bunch up, so you want to use sharp belts, high tension and moderate pressure. It's better to do it before you've finished your profile and finished grinding your bevels.

I don't know if this is adequate for what you're going for, but it works for me.
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Good idea Nate! What type of belt do you use? Jflex like when vertically finish grinding the bevels on your machined blades in your other thread? What speed do you run at for this?
 
JG Custom Metal Works said:
Good idea Nate! What type of belt do you use? Jflex like when vertically finish grinding the bevels on your machined blades in your other thread? What speed do you run at for this?
Click to expand...

I do. That's not to say it's the best belt for the job, I don't really know, but it's what I use. I usually start with 120 grit and go from there. Sometimes I need to start with 80. The finer grits are run slower. So I might start at 3000 SFM but finish at 300.

I sometimes flatten scales this way too.
 
I actually purchased one of Nathan large radius flat platens with this in mind.
May have to experiment with one 4-5'' longer for bigger blades.I seem to get
a bit of a funky grind towards the top on bigger blades unless I keep it moving pretty fast.
 
I use a Bubble Jig to align all the control surfaces of a blade especially blades that have been forged. Flatten one side of the ricasso, set the bubble in the Bubble Jig to match the platen surface, then place it on the flattened side of the ricasso and grind the opposite side. It produces a ricasso that mics 4 places. I then go on to grind the tang, and the distal taper using the same technique, before the bevels are ground. By using this technique you end up with a blade that has all matching surfaces, "before" the bevels are ground and when you go to fit it all together everything matches up. It makes it easy.
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Brett. I used a 1 degree disc for about a year and I sold it and bought the standard flat disc. For me it works with less trouble BUT I wish that I had the 1 degree off set disc back to grind long pieces. When I make parts for work rests and other jobs I need to sand a 10 inch long piece sometimes. I think I will buy another one. I am using a Rob Nielsen magnetic disc system with four discs but it saves very little time using four discs instead of one. But it looks cool. Thanks, Larry
 
Hey Larry I get what your saying. To be fair I have not used a 1 deg. taper disk much. The ones I had where actually made buy RW Wilson and .5 deg. These where great I wish he still made them as they where very close to using a flat disk. Honestly if I want something flat with out going to the surface grinder I use a 6"x48" with a glass platen and 220 belt. Just like any grinding it takes time to develop the light touch needed and some will never be able to do it. Often after much practice I can get with in a thou. measured in four place on a knife blade with the above method.
LARRYZ10 said:
Brett. I used a 1 degree disc for about a year and I sold it and bought the standard flat disc. For me it works with less trouble BUT I wish that I had the 1 degree off set disc back to grind long pieces. When I make parts for work rests and other jobs I need to sand a 10 inch long piece sometimes. I think I will buy another one. I am using a Rob Nielsen magnetic disc system with four discs but it saves very little time using four discs instead of one. But it looks cool. Thanks, Larry
Click to expand...
 
Brett, I have a second platen for my horizontal grinder and I bought a Nathan Carother D2 platen for it. I have wanted to try pyro ceramic glass but I must confess that I am afraid of it breaking and putting "Freddy Kruger" slashes on my legs and feet. Am I being overly cautious here? Some say that the hardened platens (RC 63) wear longer and work as smooth as a glass platen. What do you think? Larry
 
the hardened platen can be resurfaced, to ensure long life is better using low pressure and keep the thing and the back of the belts clean from gunk
 
Larry I say put you man pants on and put the glass platen liner on. LOL I have had many many on my grinders and the worst thing I have had is the crack. I use I high quality double sided tape to attach them and on my personal grinders get just strait plate glass as it is much cheaper and works just as well. As for which is better glass or hardened Im not sure never had the need for a hardened platen but Im pretty sure glass is harder then 62 rc.
 
Brett,
What size is the flat platen on your 6x48? I just restored and am finishing a 3hp Kalamazoo and have thought about doing Pyroceram on it. Don't know if a have the needed depth to accomplish this. Does your platen sit proud of the drive and idler wheel? What type of belt are you using? I just picked up a few ceramic belts in 60, 80 and 120 but would want a 220 for better finish but I don't think ceramic is available in 6x48. Thanks for the help.
 
Last edited:
PT Doc said:
Brett,
What size is the flat platen on your 6x48? I just restored and am finishing a 3hp Kalamazoo and have thought about doing Pyroceram on it. Don't know if a have the needed depth to accomplish this. Does your platen sit proud of the drive and idler wheel? What type of belt are you using? I just picked up a few ceramic belts in 60, 80 and 120 but would want a 220 for better finish but I don't think ceramic is available in 6x48. Thanks for the help.
Click to expand...

Pt Doc, To be honest I would just use plate glass no need for the Pyroceram. When I had them cut I had 3 made for the price of one Pyroceram would have cost. I never have used the other two as the first one lasted very well. Yes they do sit proud of the wheels a bit but to help with this I had the glass cut 47" this way the belt was not making a sharp transition from the wheels to the glass liner. I also used a a diamond file to brake the sharp edges on the ends. I also used this grinder a lot for cleaning up flat grinds. I would go to like 150 grit on the 2x72 and move to a 220 on the 6"x48" to clean everything up and true the grinds.(No two inch marks) In my opinion it works better then using the disk grinder for this. After I came of the 220 belt I hand sand the rest of the blade.
I believe the belt I was using then where the Norton norzon belts.

Hope this helps
Brett Mathews
Esteem Grinders
 
OK Brett, I am going to install some glass on my KMG stock platen. ( I will have man pants then!) Where should I buy the tape? Here are a couple photos of the blade I ground this afternoon. I finished the grind to 1200 grit on the 8 inch wheel and the flats to 600 grit on a 9" disc. After heat treat I will go through the finer grits again and grind down the 0.40 edge I left. This has taken all afternoon because I started to let the flat platen grind the one side not quite parallel so I went back to the 9 inch disc and went through all the grits to get it flat on the ricasso and the area above the grind. I will try the glass platen next. Thanks, Larry PS Do I need to install a ledge for the glass to sit on?

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Brett Mathews said:
Pt Doc, To be honest I would just use plate glass no need for the Pyroceram. When I had them cut I had 3 made for the price of one Pyroceram would have cost. I never have used the other two as the first one lasted very well. Yes they do sit proud of the wheels a bit but to help with this I had the glass cut 47" this way the belt was not making a sharp transition from the wheels to the glass liner. I also used a a diamond file to brake the sharp edges on the ends. I also used this grinder a lot for cleaning up flat grinds. I would go to like 150 grit on the 2x72 and move to a 220 on the 6"x48" to clean everything up and true the grinds.(No two inch marks) In my opinion it works better then using the disk grinder for this. After I came of the 220 belt I hand sand the rest of the blade.
I believe the belt I was using then where the Norton norzon belts.

Hope this helps
Brett Mathews
Esteem Grinders
Click to expand...

Thanks for the info.
 
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