Sharpening a large spirall router bit?

[Owen E Wheeler]

I burned a 3/4" spiral bit trying to plunge into end grain on a maple vise face. I didn't have a drill press, and the router seemed like the best choice. Didn't work, and burned the end of the flutes on the bit.

I bought a drill press and forstner bits for it; what a difference! So, my holes are cut, but I'm left with a $40 router bit with black ends on the flutes.

Is this worth sharpening? Where do I send it? I'm OK throwing it out (lesson learned) but if I can get it sharpened for less than the cost of a new one that would be a less wasteful choice.

Guide me, please....

[Cliff Rohrabacher]

Most good grinding shops can sharpen end mills and router bits. Call Forrest or whoever you send your blades to .

[Frank Drew]

Owen.

It the tool a spiral end mill? Two-flute or four? I ask because I've found that two-flute end mills do fine cutting into both side and end grain; four-flute, a bit slower cutting, so that could possibly cause a bit of burning.

I wonder if this was a mill made for opposite rotation?

[Owen E Wheeler]

Owen.

It the tool a spiral end mill? Two-flute or four? I ask because I've found that two-flute end mills do fine cutting into both side and end grain; four-flute, a bit slower cutting, so that could possibly cause a bit of burning.

I wonder if this was a mill made for opposite rotation?

Nope, it's a two flute upcut router bit, an Onsrud from Lee Valley.

[glenn bradley]

Nope, it's a two flute upcut router bit, an Onsrud from Lee Valley.

I have that bit. I use one of these (http://www.leevalley.com/US/wood/page.aspx?p=32954&cat=1,43072,43089) and these (http://www.rockler.com/product.cfm?page=2414&filter=sharpening). Sharpens the HSS right up and will take care of many chores for you in the future.

[Owen E Wheeler]

I have that bit. I use one of these (http://www.leevalley.com/US/wood/page.aspx?p=32954&cat=1,43072,43089) and these (http://www.rockler.com/product.cfm?page=2414&filter=sharpening). Sharpens the HSS right up and will take care of many chores for you in the future.

I own a small file set and that very diamond hone set. Thanks, I'll give that a go. Once I send it out and pay for sharpening, I'm spending at least 2/3 the cost of a new one, but this I can do at home.

[Joe Chritz]

I would say it is well worth while.

Dynamic saw is the service I use and I think it is like $11 for a two flute spiral router bit of HSS.

That bit has to be around $40 or $50 new.

Joe

[pat warner]

"Nope, it's a two flute upcut router bit, an Onsrud from Lee Valley. "
With a 3/4 CD? Sumpin' fishy here, steel maybe?

[Gerry Grzadzinski]

"Nope, it's a two flute upcut router bit, an Onsrud from Lee Valley. "
With a 3/4 CD? Sumpin' fishy here, steel maybe?

Yep, HSS.
http://www.leevalley.com/US/wood/page.aspx?p=42891&cat=1,46168,46173&ap=1

3/4" carbide spirals are $150+, and usually have 3/4" shanks.

[pat warner]

Owen E Wheeler "Is this worth sharpening?"

Probably not, however, don't scrap it yet.
If all you did was snooker the last 1/16", you have the whole flute left over for side cutting (only) apps. Use that up then scrap it.

[Frank Drew]

I'm still surprised that the bit wouldn't cut; HSS is harder than maple, after all.

[Thomas S Stockton]

Yes they can easily be sharpened by most sharpening shops. I would clean it up with some bit cleaner and see if that helps. You might just have a build up of charred wood and the bit is fine underneath it.
Tom

[glenn bradley]

I'm still surprised that the bit wouldn't cut; HSS is harder than maple, after all.

Too high a speed will heat up HSS pretty quick. Once you lose that leading edge profile, the heat goes up and cutting efficiency goes down. As soon as mine started to slow down I gave it a quick touch up. I did this 2 or 3 times for a couple dozen holes in 3" of laminated MDF. I ran the bit around 12k rpm (best guess).

[george wilson]

I didn't know you could sharpen HSS with a file!! I also don't advise a diamond lap. If you don't do it right,you may ruin your bit.

There is no harm in your bit getting blackened. That's just burned wood. HSS is tempered at such a high temperature that burning the wood wouldn't even come close to ruining it.

Clean off the black stuff. Try oven cleaner. Don't try to sand it,or abrade it off. You might end up with negative clearance,which would be very bad. I have sharpened spiral milling cutters by hand,but you need to know what you are doing,and make sure the cutting EDGE is the part that contacts the wood first,and NOT some area behind the cutting edge. Plus,the bit can only be touched up by hand a little before it is no longer parallel. Parallel is more critical in metal milling than in wood,though.

If the cutter is actually dull feeling after you get the black off,it needs to be resharpened in a proper machine like a tool and cutter grinder. It won't be a full 3/4" after that. You'll have to make 2 cuts if you want the full width with a reground bit.

You'd get a better deal if you had several cutters to sharpen. Years ago I could get them sharpened for a few dollars each,but since the 70's I've had my own tool and cutter grinder. My prices are probably way out of date.

Wood certainly will/can dull any bit if it contains silicon or other minerals that the tree sucked up while growing. Those little white specks sometime seen in mahogany are minerals. I don't think maple would have excessive minerals in it,though.

[Steve knight]

the problem with sharpening these bits is you change the size of them.