belt sanders -- worth getting one?

C

cognitivefun

Joined
Oct 24, 2004
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I am not intending on making knives. I use a Sharpmaker but would like to put convex edges in my blades and the sandpaper on mouse pad seems to take a long time. I see belt sanders for $40 at Harbor Frieight.

Question: what's the minimum you have to spend to get a belt sander that will work to sharpen knives effectively?

edited to add: I have read a lot of archival threads. Most are for knifemakers. I have no intention of making knives. Would a 1" X 42" work? Thanks!
 
Thombrogan, paging Mr. Thombrogan, paging Mr. Thombrogan, your presence is required. Please report in Mr. Thombrogan. :)
 
Your $40 belt grinder should work fine for sharpening. But you really have no interest at all in making your own knife? Not even a little bit?
Make sure your belts are split-but because they will be less bumpy.
-KC
 
The only sander I've ever used is a Delta 1x42, 1/3 HP. The first one I saw was at the MWKK last year, and once I got a chance I bought one for myself at Lowes. Mine was $55, but they retail for $100. I got the floor model since they were sold out. It works great, and I think the more powerful motor, bigger belts, and disc sander make it worth the extra $$ over the harbor freight offerings.
 
This thing may overheat blade and it will require HT again - especially tip. For sharpening I think manual tools are preferable.

Thanks, Vassili.
 
I agree with nozh. Start with coarser sand paper to speed up hand sharpening. I do have one of the cheap HF belt sanders and they will work just fine for sharpening but you do need to be careful.
 
Good point guys, I should have mentioned that as well. cognitivefun, I notice you've been pretty active in the HI forum. Are you interested in using this sander for khukuris? If so, overheating isn't a big concern since they're so thick and heavy. Dunk the blade in water after every pass, don't work on one area for too long and you'll have no worries.
 
Also - because of the power of this things in comparison with manual sharpening it is much easy to scrue it up and actually damage the blade - just one little mistake and edge is ruined. I heart that sandpaper on some soft surface is one of the way to sharpen convex edge.

Thanks, Vassili.
 
I'll tell you the scenario :)

"cognitivefun bought a cheep belt sander, and after sharpening 2 knives he realized that this is fantastic tool. Now it was all clear: He want to make a knife, but the sander is to small and has no power.... :( "

Choose your destiny :) :rolleyes:
 
Roadrunner said:
Good point guys, I should have mentioned that as well. cognitivefun, I notice you've been pretty active in the HI forum. Are you interested in using this sander for khukuris? If so, overheating isn't a big concern since they're so thick and heavy. Dunk the blade in water after every pass, don't work on one area for too long and you'll have no worries.
Click to expand...

Yes, this is a biggie for me...khukris, my new love (sigh).

Whatever I do I will work on my beaters first until I get the hang of things. I notice with the sandpaper mouse pad method that it works but it takes a long time and burns through a lot of sandpaper. I can't see myself sharpening my knives this way for very long.

G3d said:
I'll tell you the scenario

"cognitivefun bought a cheep belt sander, and after sharpening 2 knives he realized that this is fantastic tool. Now it was all clear: He want to make a knife, but the sander is to small and has no power.... "

Choose your destiny
Click to expand...

My destiny chooses me. Seriously, I have nothing to do with it :)

The options in the cheapie department if one move up from the Harbor Freight ultra cheapie are the Delta or the Craftsman. They are 42" belts so there are a variety of replacement belts available...anyone have any opinions on those?



Thanks very much for your very helpful responses!
 
I have a Craftsman 2x42. It works great for convex grinding and shaping handles. The platen vibrates way too much to do a decent flat grind. For an $80 grinder I'd say I got my money's worth, but I'll probably get a Grizzly 2x72 this year and just use the craftsman for shaping handles.

And I agree with G3d, once you start down this path you'll probably want to make a knife or ten. :D
 
Thanks, Easy.

Cognitivefun,

It's worth the $38 shipped to get a Harbor Freight sander. Also, go to some place like www.leevalley.com and get some higher-grit belts. Currently, I'm using the stock 80x belt, 15micron belts from Lee Valley, and a homemade strop with CrO/AO from www.buffingunlimited.com ($11 for three pounds shipped. What a deal!) and the results are great.

Move the blade smoothly, lightly, and quickly across the belt. Do one pass, wait 10-30 seconds, repeat on the other side. This will let you remove as much steel as needed without overheating the blade. Do not dip the knife in water. Move the knife quickly, lightly, and smoothly to prevent overheating and take the extra time to let the knife cool in the air just in case. Quenching in water can cause the edge to do undesireable things (going from too hot to too cold).

Do not use the platen and try to flat grind. It doesn't work so well. For that, you'll need to buy a higher-quality (read "much more expensive than two EdgePro Pro models without the angle matching of the EdgePro Pro model") belt sander.

For convex grinds, the Harbor Freight 1x30 is the bee's scary-sharp convexed knees.

Oh yeah, protective eye wear and a respirator are always good ideas as is sharpening tool steel just to watch the sparks.
 
thombrogan said:
It's worth the $38 shipped to get a Harbor Freight sander. Also, go to some place like www.leevalley.com and get some higher-grit belts. Currently, I'm using the stock 80x belt, 15micron belts from Lee Valley, and a homemade strop with CrO/AO from www.buffingunlimited.com ($11 for three pounds shipped. What a deal!) and the results are great.
Click to expand...

Thanks!! Much appreciated.
 
You may want to check out Grizzly Industrial also.
They offer some nice belt sanders at reasonable prices.
I bought a 1x42" (not offered by them anymore) about 8 years ago.
It has been a true workhorse.
Tracks great, enough power for most jobs.
Extremely reliable, I have never had a seconds problem with it.
I can take a lawn mower blade that has been beat up completely, and have it super sharp in a matter of minutes.
Unbeatable for large hatchets/axes.
There are MANY senerios where a sander is just the right tool.
I find it indispensable.
With a large selection of grits (I have seen 2400 for the 1x42"), and even leather belts that can be charged with rouge (for sharpening), and scotchbright belts for removing rust, or finishing blades, you just can't go wrong with a belt sander.
Everyone should own one, as they are simply an amazing tool for a knifenut!
 
Where would you keep a sander in your house if you lacked a workshop? I have spare bedroom or a laundry room. I wonder if it's something that you can set up easily when you need it? Does it require a dedicated table?

These may be dumb questions but I just do not know the answers. Thanks.
 
Take it outside or the garage... belt sanding will leave a coat of fine metal or other material all over the apartment...

Really! :eek: I know from experience...
 
I keep my sander in the garage since I use it a lot. When I take it to a friend's house to sharpen all of their kitchen knives I work outside. When I take it to the local soup kitchen to sharpen all of their knives I work on a dining table and do a lot of cleaning afterward. If it's real cold in the garage and I am only sharpening one knife I'll do it in the family room.

My tips to avoid burning and damaging the blade are--
--Work with enough light on your sander.
--Use a light touch.
--Hold both the handle and the blade, not just the handle.
--Do not wear gloves so you feel blade heat (and this is safer).
--Use the side of your finger or thumb that is holding the blade to just slightly skim the belt occasionally to control your grinding angle.
--Always grind with the edge upwards running into the belt so that you transfer heat away from the edge into the body of the blade. (When you grind edge-first cold grit contacts the edge area and the removed metal gets hotter as it moves towards the spine of the blade. Since the blade gets thicker as you move up the bevel towards the spine this part of the blade will not get as hot as if the equivalent heat went into the miniscule edge. If you grind edge-trailing this hot metal comes from the back of your bevel and reaches maximum temperature at your edge.) This also reduces excess burr formation.
--Be particularly light as you approach the point. The curvature in that region makes the grinding fast there and the heat is concentrated into a smaller volume. This is the commonest place to burn your blade.

Finish your sharpening manually. This gets rid of any burr and insures that the final microscopic edge does not have a compromised heat treatment. A Sharpmaker does a good job for this. It only takes a few strokes.
 
It use to be that a cheap belt sander was cheap. Now days the difference between the cheaper ones and the good ones has gotten a little "fuzzy". If you look at a craftsman, delta, or harbor freight, you may find allot of similarities between them. Many of them are now made in China, or taiwan!

I have an old delta that has a cast iron base, american made motor, been around since the 60's. The ones I have seen now, are not much different then the chinese made ones. Much of that stuff is made overseas now. There is no comparison between the quality of my old one, and th new ones. My old one is much better. However, the ones you get now from harbor freight are decent enough to use. You do not have to buy an expensive one to get good results. Its hard if you cannot look at it first before you buy it. We have a harbor freight here, so if I want something, I try and go look at it in the store (also saves on shipping).

Even some of metal bandsaws that HF is selling are pretty decent. That country is practically putting america ouf of business in may areas now (different subject though).
 
For regular sanding belts that aren't made from leather, Scotch-Brite, or mithril mined from the darkest regions of Mordor and Narnia (such as 3M's 15 micron 1x30 belts sold by Lee Valley), edge-leading is a superior choice for the reasons mentioned by Jeff Clark. I tried it with a 15 micron belt, heard a frightening pop, and went back to edge-trailing after replacing the belt.

If you use such non-standard belts, you'll still be using the coarse belts for the majority of your reprofiling efforts, so sticking with edge-trailing is a better idea (despite slightly inferior performance and larger burr formation) only because your tough-belt habits can end up accidentally destroying your delicate belts.
 
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