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Marko Tsourkan
05-21-2011, 04:45 PM
How do you guys go about cutting knife blanks (for stock removal) from a sheet? I have a Milwaukee Deep Cut portable band saw that I am to use for some cutting, but I don't think it will allow me to cut a strip from a sheet.

If using an angle grinder with a cutoff wheel, does the cut generate a lot of heat so that might affect the straightness of the blank? The steel I have is oversize 5/32 52100. Pretty thick stuff.

Thanks,

Marko

El Pescador
05-21-2011, 05:50 PM
Never cut knife blanks but angle grinder with the hose running on the sheet gets me through 3/8 plate just fine...just know that you go through discs faster than you can change them.

Pesky

SpikeC
05-21-2011, 05:54 PM
Diamond coated discs are available for angle grinders, I wonder how one of those would work?

Marko Tsourkan
05-21-2011, 06:10 PM
... angle grinder with the hose running on the sheet ...

Pesky

Care to elaborate?

Bill T
05-21-2011, 07:49 PM
It's tedious , but drilling holes then playing connect the dots works for some .

El Pescador
05-21-2011, 07:53 PM
Duct tape the end of the hose so the water runs across the sheet of steel. I set this up outside clamped to a table. Use a carbide cutting wheel. This isn't something I do very often. Most of the time just the wheel w/o the water.

Pesky

l r harner
05-21-2011, 07:57 PM
i had a little HF 4x6 saw and killed it then got a clark 4x6 (they are all about the same) after finding a new way to brake that saw i bucked up and found a used roll n saw
800LB of killer band saw with self feed

El Pescador
05-21-2011, 07:59 PM
Water and electricity don't mix...unless you're kinda stupid like me! The big thing is you're not cutting through a stream of water...you're using it as heat sink close to the cut.

Pesky

Marko Tsourkan
05-21-2011, 08:16 PM
i had a little HF 4x6 saw and killed it then got a clark 4x6 (they are all about the same) after finding a new way to brake that saw i bucked up and found a used roll n saw
800LB of killer band saw with self feed

Yeah, I would love to get a rollnsaw, but not in the plans for a while. So, angle grinder with a cutoff wheel and clean up on a Milwaukee hand held band saw.

:)

Delbert Ealy
05-21-2011, 08:17 PM
I don't,
Now I know that may not sound very helpful, but I just don't buy stock larger than I can cut with the tools I already have. I don't buy plate, I buy strip. The only real reason to buy plate is for waterjet cutting blanks, where the cost/benifit is on your side. On the other hand, if you got the material at substantial savings or it was the only way to get that thickness, than I understand. In that case, find a local fab shop with a shear. Tell them what you need and if they can do it. Shear to a width that you can cut blanks out of and you are all set. In a pinch call Aldo Bruno, I think he has a shear that can handle that stuff.
Del

watercrawl
05-21-2011, 08:17 PM
I have a HF 4x6 that cost me all of $180 with their sale and a coupon. You can set it vertically and put a work table on it turning it into a vertical band saw which is something not really clear or at least wasn't to me until I saw one in the store. Works good, but cutting metal with a bandsaw is tediously slow. An angle grinder is faster but not nearly as accurate and throws sparks all over the place and makes the steel red hot and throws tiny shards of steel all over and is generally far more not good IMHO. I started with the angle grinder, but quickly bought the metal cutting bandsaw and am far happier with it.

Marko Tsourkan
05-21-2011, 08:34 PM
...In a pinch call Aldo Bruno, I think he has a shear that can handle that stuff.
Del

Damn, that is where I go the steel from. Should have asked him to shear it.

Is there any risk to cut the blank with a grinder? Heat build up, warping, etc?

Any of you guys use Milwaukee hand held band saw mounted vertically? I think I saw it in Stefan's video.
I have one but need to build a custom table for it.

M

watercrawl
05-21-2011, 08:57 PM
There is a guy that makes stands for the Milwaukee band saw that look real nice and aren't too spendy.

watercrawl
05-21-2011, 08:59 PM
http://www.swagoffroad.com/Porta_band_Modular_Mount_Product.html

Rottman
05-21-2011, 09:12 PM
Is there any risk to cut the blank with a grinder? Heat build up, warping, etc?

Cutting strips with a shear is more likely to give you warping than any angle grinder could produce.

RRLOVER
05-21-2011, 09:18 PM
I have an angle grinder in my right hand and a spray bottle to keep things cool in my left hand.A welding jacket is a must unless you want to put holes in your cloths.

watercrawl
05-21-2011, 09:29 PM
I have an angle grinder in my right hand and a spray bottle to keep things cool in my left hand.A welding jacket is a must unless you want to put holes in your cloths.

Speaking of that kind of thing, I don't wear anything but cotton when I'm working with things that make sparks.

Marko Tsourkan
05-21-2011, 09:32 PM
Speaking of that kind of thing, I don't wear anything but cotton when I'm working with things that make sparks.

I have a 46" welder's leather apron (inspired by Bob Kramer video, though he has a blacksmith apron :) ). It comes very handy in metal working as well as wood working.

I am mostly concerned about whether I need to normalize steel after cutting out the blank.This is a thick steel, so there will be heat created by cutting and possible warping.

Looks pretty good (the table for Milwaukee) Adam. I might get one after all.

M

JohnnyChance
05-21-2011, 10:45 PM
Cutting strips with a shear is more likely to give you warping than any angle grinder could produce.

Not a giant stomp shear. Handheld shears on thin sheet metal yes, but a stomp shear or break will cut them cleanly.

Michael Rader
05-22-2011, 02:02 AM
Know anyone with a plasma cutter? Cut it 3/16" over-sized and grind out the heated zone. Shouldn't warp much. Plan on doing more of these? Definitely water/laser cut next time. Or get your own Plasma cutter. I use mine a lot.
-M

JohnnyChance
05-22-2011, 02:17 AM
I dont have a plasma, just a torch. Much bigger heated zone I am sure. But 5/32" is pretty thin, it would cut pretty quick.

2 saw horses, a couple of clamps, and a sawzall?

Rottman
05-22-2011, 08:27 AM
Not a giant stomp shear. Handheld shears on thin sheet metal yes, but a stomp shear or break will cut them cleanly.
I was talking about a stomp shear. It will cut cleanly but thinner strips tend to corkscrew.

l r harner
05-22-2011, 09:22 AM
if you shear cpm steels at room temp you risk shattering the sheet (ask aldo about that or carpenter for that matter)

sawzalls seem to move the blade too fast for a a nice cut and blade life is jsut plain bad

safest way tho a bit slow depending on the settings is that little 4x6 tupe saw witha big thick table put o it and a seat in the vice part you jsut have to know how to mark the steel so as to deal with ath only 4 inch wide max cut

i did get lucky and picked up my "new" saw used and for about half price (USA built tools are not cheap)

Marko Tsourkan
05-22-2011, 09:41 AM
Thanks everybody. Just one more question.
If there is warping after cutting steel with an angle grinder, can it be straightened by hand (and later ground flat after HT), or other steps are required to relieve stress before HT.

M

rockbox
05-22-2011, 10:20 AM
I use an angle grinder now. It does create a lot of sparks but I have no problems with warping. Heat is not a problem since you are going to heat treat afterwards anyway. However I was thinking of using a jig saw or a reciprocating saw. Jigsaw would be better since I could actually steer the it.


http://www.youtube.com/watch?v=fWpHzf1I0BI

Marko Tsourkan
05-22-2011, 11:17 AM
Sparks don't bother me as much, my concern is warping that needs to be dealt with through stress relieving, hand straightening, or grinding off.

M

PierreRodrigue
05-22-2011, 11:22 AM
An angle grinder, with a good quality thin zip wheel, leave a wheels width of metal outside your scribe lines, and finish grind to profileafter. On thicher material, I make a few passes along the length of the cut so as not to go full thickness on the first pass. never had any warping, and never had any issues with the heat generated. Very rare to see the steel turn red if you make a couple light passes. I started buying sheets because no matter who cuts it, they want to add cost. I ordered the last sheet from Aldo. the sheet is nice because you can "nest" a few different patterns when laying them out to reduce a large percentage of the wast associated with buying strips of set widths.

Marko Tsourkan
05-22-2011, 11:41 AM
Hi Pierre,
I think I have seen your name and a phone # on a sticky pad in Aldo's office. I was wondering if it was you.

I have an angle grinder with a cutoff wheel, so this is how I will proceed for now. No plans for plasma cutter at the moment, have other priorities. Water jet blanking sounds interesting, but I have no companies (that I know of) in the area and schlepping back to NJ sounds like an ordeal. So, I will have to use what I have.

A nice bandsaw would be great down the road, but might take a while, as I would look for a quality saw.

Thanks folks,

M

JohnnyChance
05-22-2011, 12:00 PM
i cant recall ever having warping after cutting with an angle grinder. i like the thin discs, and buy them in bulk when possible. i know they are a couple bucks each, but i prefer switching to a fresh disc than trying to squeak every millimeter out of each disc. the sparks dont bother me either.

Marko Tsourkan
05-22-2011, 01:30 PM
Does it matter which way you lay out your knives on a sheet ?

SpikeC
05-22-2011, 02:02 PM
I cut with a regular hand held jig saw and use about one blade per piece. I have done more hand planes than knives, butt the knives are catching up fast!

rockbox
05-22-2011, 02:07 PM
I cut with a regular hand held jig saw and use about one blade per piece. I have done more hand planes than knives, butt the knives are catching up fast!

I wanted to start using my jig saw instead of my grinder. Can I turn the blade on metal like wood and what kind of blades do you use?

Aldo Bruno
05-22-2011, 02:54 PM
Marko,

http://www.leadingedgefab.com/knife-makers

It's all you need to know.

Your concerned steel provider :)

Marko Tsourkan
05-22-2011, 03:05 PM
Aldo, I can't wait till you offer this service yourself in house. Shipping to MI would be a killer.

M

SpikeC
05-22-2011, 04:49 PM
I wanted to start using my jig saw instead of my grinder. Can I turn the blade on metal like wood and what kind of blades do you use?

I use Bosch blades and drill holes where I need to change directions. Curves are problematic, but gentle ones or no problem, as in the cutting edge profile.

SpikeC
05-22-2011, 04:51 PM
Marko,

http://www.leadingedgefab.com/knife-makers

It's all you need to know.

Your concerned steel provider :)

Do you have any idea how much a single prototype blade might cost, ballpark?

Aldo Bruno
05-22-2011, 06:23 PM
Do you mean starting up a $200,000 dollar water jet machine and making "1" piece?

SpikeC
05-22-2011, 06:30 PM
yup!

Marko Tsourkan
05-22-2011, 08:31 PM
Do you mean starting up a $200,000 dollar water jet machine and making "1" piece?

Have a number of makers commit to your service (in writing) for the minimum of two years in exchange for top notch customer service and good price. No?

M

rockbox
05-22-2011, 10:31 PM
From what I've seen, most companies charge 5-10 dollars a piece depending on quantity. Sometimes there is also a setup fee. I imagine once the cad drawings are in the system, the setup fee is waved on subsequent orders.

l r harner
05-23-2011, 08:09 AM
the real short of it is less you are getting 20 or more parts cut its almost not worth sending out
i thin most of you are jsut used to cutting wood on wood saws band sawing steel is much slower but its not bad on long slow curves (think of all the tringles you need to cut out of a complex shape cause metal saws can turn as nicley as a wood saw with thin blade

one thing that can help you get a part count up is making a "stock" handle shape then jsut haveing an oversized blade like shape that you can do a bit of moding on to make a few types knives. i have razors lasercut with jsut the tang shaped and the blade a big rectangle that i can shape in house to the needs of the buyer (the tang is the time eater at the saw)

Marko Tsourkan
05-23-2011, 08:31 AM
So is it really $5-10 a blank if laser cut? Sounds reasonable (if $5), given the amount of work that goes in particularly on thicker steels.

M

rockbox
05-23-2011, 08:53 AM
Yes it is if you are doing a whole sheet at a time but you also have to factor shipping and setup. If setups 50 bucks and shipping is 10 dollars each way. Then it wouldnt make sense for anything less than 10.

Marko Tsourkan
05-23-2011, 09:06 AM
Yes it is if you are doing a whole sheet at a time but you also have to factor shipping and setup. If setups 50 bucks and shipping is 10 dollars each way. Then it wouldnt make sense for anything less than 10.

Right. I thought of what Butch said, of getting handle and general shape and then do variations on a grinder.

I will try to look if there is a company near by and somebody with Cad software skills.

Not a big fan of an angle grinder. Smell, sparks and a gushing wound on my index finger from not paying attention.

M

watercrawl
05-23-2011, 09:19 AM
Marko -

Call this guy:

http://www.greatlakeswaterjetinc.com/

l r harner
05-23-2011, 10:28 AM
so we will keep with the razor setup as thats the only thing i have ever had cut out for me
steel 52100 400$+S&H
the cut was about 5 bucks a razor and i needed 50 to get no art fee and ended up getting 114 made from that sheet (i also got to keep the web of the sheet to later use in a dammy mix)

the cutter was local so i saved on that part of shipping
you can see how you can start getting a really nice chunk of change needed for the batch and all that $$ is up front and only for one patteren. while the blades dont rot like food im still working on blades from that batch now nearly 2 years later. kind of need to ask yourself what you want to invest in cause at that point you are investing and hopping that you can sell the pattern/ steel type you picked VS maybe a new grinder or saw thats a bit slower but gives you more options down the road

Marko Tsourkan
05-23-2011, 12:32 PM
Makes sense. I was just exploring the options. I have 2x4 sheet of 52100 and a smaller sheet of W2 so it's not really that critical for me to outsource blanking. And besides, I will be getting some of my steel from Devin, so it will be in strips. A good bandsaw would be preferable, but for now I will make a use of a Milwaukee handheld saw.

Thanks again, everybody -

M