Wood chipper blades Help

[epw314]

I have 4 double edged chipper blades to do for a tree surgeon.They are 1/2" thick which is no problem. I'm using the planer blade jig by removing 2 studs.The angle is to be 31 degrees.The factory grind is 7/8" inch long.I can't get it to go back that far,Am I doing something wrong or did the factory use a  very large wheel?Costomer states that the taper needs to be back that far.To me 31 degrees is 31 degrees.
Thanks,
Ed

[Jeff Farris]

Ed, check the angle with the AngleMaster check angles around the outside. Sounds like the angle is greater than 31 degrees, if you're setting it to 31, but the original bevel is longer.  

If the customer wants the bevel that long, just match the bevel, rather than setting the angle to the guide.

[Dadio13]

I have a landpride model WC 1504 chipper with four double sided blades, each about 6 inches long, 2 inches wide and 1/2 inch thick.  I have been sharpening these blades manually as no attachment I can find will hold the blade.  Which leads to an inconsistent edge/sharpness. The planer blade jig is not big enough to hold the landpride blades.  Can't see to modify the planer blade jib because it would entail damaged to the jig.  Any suggestions?

[Ken S]

Welcome to the forum, Dadio.

Let me state up front that I have no knowledge of chipper blades. That said:

I think it is important to differentiate between damage to the jig and intelligent modification to adapt the jig to another purpose, even if the modification means the jig will no longer work for the original purpose. This means you would need to purchase a second jig if you sharpen planer blades. You must judge if the amount of chipper blade work involved warrants the cost of the modification and possibly purchasing a second. From personal experience I would recommend working with a machinist unless you have the necessary skills.

Keep us posted!

Ken

This is a process which should be done thoughtfully, with an eye always on safety. Hopefully other forum members will chime in with ideas.

[SharpenADullWitt]

I am trying to wrap my head around this, as no pictures, makes it harder for me to understand.  How would you have to modify the jig, so it would be damaged and unusable as a planner jig?  Have any other jigs?
This is where I am picturing something like like Herman's or Ionut's small jig modifications, being useful for something larger:
http://forum.tormek.com/index.php?topic=1560.0
I am still trying to wrap my head around the holding of the blade (since two sided), as I am trying to picture it sandwiched, and my head keeps mentioning magnets, in some slot to allow movement back and forth.

[Jan]

Try to mount the knives in the Long knife jig where you have replaced the screw (3) and the tightening knob (4) for longer ones.



Jan

[RichColvin]

I recommend using the SVD-110 tool rest.  You could affix a block of wood to the tool rest using clamps, and the blade can be move side to side, holding it firmly against the wood block to keep the blade's edge straight.

Some examples are below.  The first one is for a blade which is less than 3½" wide


and the second one is for a blade which is greater than 3½" wide.

[Ken S]

Are chipper blades anything like miter guillotine blades? (See the illustration in the handbook). If so, just removing one or two of the Allen screws might solve the ptoblem.

Ken

[Jan]

Very nice pictures, Rich, appreciated! 
The situation shown in your sketches is for edge angles roughly 60°.

It may be challenging to ground an edge angle of 30° using the Tool rest. For this angle and vertically mounted USB the outer edge of the Tool rest cannot be positioned near the grindstone surface. For short tools the handbook mentions the following asymmetrical placement of the Toll rest.



In my opinion an edge angle of 30° can be sharpened when USB is mounted horizontally, but in this case the guiding effect of the wooden bloc will not be fully effective because the knife will be pulled towards the stone.

Jan

[Ken S]

A second thumbs up for your drawings, Rich.

My version of Herman's platform used the Tormek platform instead of the scissors jig. (Herman's works better, due to the lower center of gravity of the scissors jig.) Before attaching a longer platform, I tried turning the platform around. By substituting a 6mm flat head bolt for the Tormek locking screw, I could get closer to the grinding wheel. I could not get close enough for a fifteen degree bevel angle.

However, I believe the flat head bolt trick would work for a thirty degree bevel angle with the platform turned around (Imagine Rich's drawing with the long side facing the grinding wheel.)

I am presently away from home. I will try this when I return.

Ken

[Jan]

Yes, Ken, you are correct! 

When the long side of the Tool rest is facing the grindstone and the Tormek knob is substituted by a M6 flat head bolt you can grind a 30° edge angle.

Even better results you will get when you make two threaded holes near the side edges of the platform where they will not collide with the grindstone. In this case you can sharpen even a 20° edge angle. 



Jan

P:S.: Please note that the edge angles that we can sharpen depend on the thickness of the tool and on the diameter of the grindstone. The range of edge angles we can sharpen is diametrically different for a 1/2"  thick tool and a 1/8" thick tool! The difference is the same as between an edge angle and a heel angel.

[AlfA01]

Old thread here, but I'm looking into sharpening some chipper blades.  I believe hey are single edge at 40 degrees. 

It's a used chipper and will not feed limbs correctly, which I think has something to do with blade angle and sharpening angle. 

I was thinking to use the side sharpening jig MB100 for this that I've ordered off of eBay recently.  Any thoughts on using the side sharpening jig? 

[RickKrung]

No specific thoughts, other than it ought to work and that is what I would try doing.  Seems like the perfect tool for the job.  I am interested in hearing how it goes.  Please keep us posted. 

Rick