Material Removal From HT'd Blade?

A

AlongTheRazorsEdge

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Jul 8, 2021
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225
Hi,

What would be the best route to semi to heavy material removal from an already heat treated/tempered blade? In other words, how to radically reduce weight of an existing knife/tool without overheating the steel? I know of wet (coolant) bandsaws and have seen wet (coolant) grinding wheels, but are there wet belt sanding set ups that would make this task safe (avoiding overheating) and relatively easy (faster than by hand and precise)? I have a hatchet that I would like to radically lighten by removing material evenly and precisely from both sides of the head. Thank you!

ATRE
 
It is a really ghetto-grinding method, but I saw a video of a fellow who clamped the blade to a picnic table, put a brick on a hose that sprayed a small stream of water on it, and used an angle grinder to work down a hardened blade. IIRC, he was making a camp knife from a machete. I assume he went to the belt grinder and cleaned it up with the grind-and-dip method to make it smooth again.
 
Thank you for the replies! Not sure if using an angle grinder in/near spraying water is the safest (safety wise) but it probably did keep the work piece cool lol! I have seen the grind and dip method before but was wondering if there were any wet belt setups out there similar to the other wet tools described. When the time comes I will just take it easy (more, shorter passes) and keep dipping as suggested. Thank you again.

ATRE
 
That's kinda Iike using a blow dryer in the bathtub, not a good idea.
 
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Sorry, I thought you were looking for alternatives to using a 2X72 grinder,

Wet belt grinding is done with a mist spray setup called a Kool Mist system. There are very low-cost clones on Amazon and Ebay. I do recommend the Kool Mist concentrate, as it seems very good at creating the mist and reducing rust. You need a reasonable size compressor to create the mist. Many grinder belts are waterproof. Check the specs for the belts you use. Most ceramic belts are wet-or-dry.
 
Stacy E. Apelt - Bladesmith said:
Sorry, I thought you were looking for alternatives to using a 2X72 grinder,

Wet belt grinding is done with a mist spray setup called a Kool Mist system. There are very low-cost clones on Amazon and Ebay. I do recommend the Kool Mist concentrate, as it seems very good at creating the mist and reducing rust. You need a reasonable size compressor to create the mist. Many grinder belts are waterproof. Check the specs for the belts you use. Most ceramic belts are wet-or-dry.
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Looking to plan for the future which will include some sort of belted grinding setup. This particular project (not any time soon) will consist of removing large amounts of material from a ready made production hatchet, but I do want the removal to be even and appear factory so I think a belt would be the way to go to maintain the factory lines. Thank you for mentioning the Kool Mist system, using that in a search brought up what I was looking for!

I will be back at some point to ask about belted machines in general. From what I understand (limited lol) there are no off the shelf belt grinding setups optimized for knife and tool making, so I will need some help. I will also be looking for some type of jig/fixture setup for consistency (even/symetrical and repeatable grinds).

Thank you again!

ATRE
 
There are dozens of "off the shelf" knifemaking belt grinders. Bader, KMG, Reeder, Northridge, TW-90, Burr King, ........and on and on. At any one time there are usually two or three threads running on Shop Talk about them. A starter belt grinder is around $1000USD. A full function grinder with the needed accessories and power is $2000-5000. There are some cheaper alternatives, but they won't do the task you are desribing.

Jigs are a help and a curse. They may do one task OK, but limit what you can do and don't teach you how to do it properly by hand. Most of the time hand grinding is smoother and better than a jig.

You didn't fill out your profile with any info on where you live. That is important for getting good advice. Someone near you might offer to do it for you or help you do it.
 
Stacy E. Apelt - Bladesmith said:
There are dozens of "off the shelf" knifemaking belt grinders. Bader, KMG, Reeder, Northridge, TW-90, Burr King, ........and on and on. At any one time there are usually two or three threads running on Shop Talk about them. A starter belt grinder is around $1000USD. A full function grinder with the needed accessories and power is $2000-5000. There are some cheaper alternatives, but they won't do the task you are desribing.

Jigs are a help and a curse. They may do one task OK, but limit what you can do and don't teach you how to do it properly by hand. Most of the time hand grinding is smoother and better than a jig.

You didn't fill out your profile with any info on where you live. That is important for getting good advice. Someone near you might offer to do it for you or help you do it.
Click to expand...

Thank you. I have a lot to learn. I had heard that folks generally fabricate their belt set ups, maybe that was for specific, non standard belt widths etc. I will look into the ones you mentioned and also do a lot more reading in general. My experience with belts is limited to wood and pedestal style, general purpose shop set ups (hard backer, no slack) doing things like shaping rough cut metal brackets, shortening fasteners etc.

As far as jigs/fixtures, I think I understand what you mean. It's seems that they can be a crutch in a way. Like a guided sharpening system v.s. hand sharpening on stones; a guided system will be very precise and repeatable with blades styles that work well (clamp well etc.), but what about blades that are outside the limitations of the system? Hand sharpening may be the only option in that case and knowing how to do it properly gives the skill to sharpen any blade, either at home/shop at a work bench in comfort or in field conditions if necessary. I can see how having skill grinding free hand would likely mean better results even when using a jig/fixture for repeatable volume production.

Thank you again for everyone's help and suggestions, I do appreciate it.

By the way, this is the hatchet in question

Evidently it is drop forged 1055 carbon steel, differentially heat treated. The hatchet is a bit over 2 lbs in factory form, I'd like to reduce that significantly while maintaining the same shape by taking material evenly off of the cheeks and at the butt/poll. There is a ton of excess material. This hatchet hits hard and bites very deep (granted at least partly due to the factory weight), I believe the straight cutting edge and squared heel/toe play a big part in it's performance. Significantly reducing the weight will hopefully make it easier to haul around and swing without negatively impacting performance in my use.

ATRE
 
For that hatchet job you could just use a cheap Harbor Freight belt grinder. It's gonna eat a few belts though!
 
if the steel is in fact 1055 anneal it and re forge it how you want it to be .. the heat treat of that steel is real easy..
heat to 1495 /1500 ( check temp with table salt) quench in hot oil temper ands be done with it..
you could build a small forge out of a pipe or couple of old coffe cans.. a burner or 2 is easy to make and connect to a bar b que propane tank..
often times people try too hard to reuse a material instead of using the original item as a base metal that is close to the size/shape you want.
pounding it thinner would take the minimum of effort..
 
All these would be good suggestions if the OP was a smith with a forge and shop. But he is not.
He is looking for a simple and cheap way to thin the head. I don't think that is a good idea, but it is his hatchet.
The best suggestion is an HF belt grinder.

Maybe someone in Florida will invite him over to do it together in their shop.
 
Stacy E. Apelt - Bladesmith said:
All these would be good suggestions if the OP was a smith with a forge and shop. But he is not.
He is looking for a simple and cheap way to thin the head. I don't think that is a good idea, but it is his hatchet.
The best suggestion is an HF belt grinder.

Maybe someone in Florida will invite him over to do it together in their shop.
Click to expand...

Correct, not a smith by any stretch lol! I would love to make knives and tools maybe one day, I have ideas for knives/tools that I would love to have but aren't currently or readily availible. It would likely be years before I would be able to do so though. In the mean time I'll try my hand at some modification of existing knives/tools and try to learn as much as I can.

The HF belt grinder sounds like the ticket for me at this time and I could use it for other projects. I may try to piece together a DIY misting setup just for peace of mind in not ruining the HT/temper. Otherwise, I will just take it very slow, small amount of material removal at a time, dip in water and repeat until complete.

Thank you!

ATRE
 
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