How To Magnacut surface grinding question...

A

AbLonewolf

Joined
Jan 30, 2020
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So I ordered some Magnacut bars : 3/32"/1.5" material. I proceeded to surface grind some blades before sending it out for heat treat. Part of the bar was deeply "pitted". I don't want to go too deep in fear of screwing it up as most know, this stuff ain't cheap.

1) Did I get a bad bar? If so, is this a common occurrence with Magnacut?
2) Suggestions on how I could fix the blades the best way I can prior to sending them out for heat treat?

Thanx...
 
Here's a couple of pics.

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No, it isn't a bad bar. You purchased unground stock, which has the mill finish still present. To avoid this order flat ground stock, which will have the mill scale removed
 
Usually when a supplier sells unground stock it is a bit thicker than the listed thickness to accommodate surface imperfection removal. I would mic out the bars to see what the actual thickness is. I wouldn't be surprised if it is .100 or so if it was sold as 3/32 (.094).
 
Usually, but not always. Alpha lists thickness in thousandths, some others do not. The scale on magnacut is very rough on belts. It's worth it to buy flat ground stock
 
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I don't find Magnacut mill scale to be any worse then any of the other CPM steels and I personally would never buy flat ground from a middle man as the prices are outrageous.
 
AbLonewolf said:
1) Did I get a bad bar? If so, is this a common occurrence with Magnacut?
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We process thousands of pounds of blade steel every month. The surface defects shown in your photos are common. We see defects from every steel manufacturer we buy from. The exceptions are cold rolled alloys.

Surface defects, thickness run out and HIP can are the major reasons why we chose to flat grind all expensive alloys. We want knifemakers to receive material that is ready to use. This is the same philosophy we have regarding annealing.

Each piece of flat ground steel is measured in multiple places. We define “flat ground” as +-.001" over 12 inches. There is needless confusion about flat ground steel. Ignore what it is called and look at the tolerances. If no tolerances are listed or if the tolerances are excessive, keep looking

Seedy Lot said:
I personally would never buy flat ground from a middle man as the prices are outrageous.
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I don't know if we are a middle man but our pricing for flat ground Magnacut is less than some competitors unground Magnacut.

Chuck
 
Alpha Knife Supply said:
We process thousands of pounds of blade steel every month. The surface defects shown in your photos are common. We see defects from every steel manufacturer we buy from. The exceptions are cold rolled alloys.

Surface defects, thickness run out and HIP can are the major reasons why we chose to flat grind all expensive alloys. We want knifemakers to receive material that is ready to use. This is the same philosophy we have regarding annealing.

Each piece of flat ground steel is measured in multiple places. We define “flat ground” as +-.001" over 12 inches. There is needless confusion about flat ground steel. Ignore what it is called and look at the tolerances. If no tolerances are listed or if the tolerances are excessive, keep looking


I don't know if we are a middle man but our pricing for flat ground Magnacut is less than some competitors unground Magnacut.

Chuck
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On what size stock are you comparing price? You don’t even sell full length bars, when you compare your prices to prices of full length bars every supplier I’ve purchased magnacut from is cheaper for a longer bar than what your prices would be for the same length of material chopped up. Personally I’d prefer surface grinding to be an option rather than standard so I can choose if I want that done or not.
 
Joshua Fisher said:
On what size stock are you comparing price? You don’t even sell full length bars, when you compare your prices to prices of full length bars every supplier I’ve purchased magnacut from is cheaper for a longer bar than what your prices would be for the same length of material chopped up. Personally I’d prefer surface grinding to be an option rather than standard so I can choose if I want that done or not.
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Did you post as a shill for Pop's again or are you posting for yourself?

This thread is about surface imperfections in steel, not about your personal problems with my business. Stay on topic and do not distract from the topic of this thread.

Chuck
 
Alpha Knife Supply said:
Did you post as a shill for Pop's again or are you posting for yourself?

This thread is about surface imperfections in steel, not about your personal problems with my business. Stay on topic and do not distract from the topic of this thread.

Chuck
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You were the one that mentioned price in your post, I’m sorry that the statement you said was incorrect/misleading. I’m my own person and any recommendations or endorsements I give are because I’ve had good interactions with a given supplier, maybe instead of taking the time to insult someone you should give thought to the criticism to improve your business and how you interact with potential customers. As for staying on topic I’ve noticed the mill scale on magnacut seems to vary a good bit, but that said I’ve not used a lot of other cpm steels in a large enough quantity to be able to fully compare. For the Original poster you should be able to grind a bit deeper to remove any imperfections you don’t want, it will only result in a thinner blade just be sure to remove an equal amount of material from both sides. The mill scale is definitely harder to grind off after heat treating.
 
Alpha Knife Supply Alpha Knife Supply I am no middle man just thrifty. I have bought thousands of dollars of steel from you over the years Chuck.

Taking your current prices it would cost me $27.60 per knife in flat ground Magnacut for a pattern that I can get 2 blanks from given your standard steel sizing. From a competitor of yours I am paying $13.21 per blank for mill scale finish with same pattern.

If i get into a bigger pattern then price difference is going to be much larger as your standard size lengths, while being convenient for shipping, end up often leading to much wasted steel.
 
I will clarify topics brought up in previous posts.

Magnacut flat ground pricing
After my first post I searched and verified that my flat ground pricing is less than some other supplier’s mill finish pricing.

You don’t even sell full length bars
The longest billet of blade steel we sell is 35.5”. The longest flat ground piece is about 30”. There are two reasons for the length difference:
1) Longer bars will not fit on our Blanchard grinder
2) We do not have room for the additional pieces
Both problems will be resolved. When the new grinder is installed we can grind up to 60” long. When we move to our new office we will have lots more room for materials.

I’d prefer surface grinding to be an option
We are continually collecting requests from our customers. One of the advantages of being in business for more than 20 years is we have lots of data to work with. One frequent request is for precise flat ground steel.

Buying flat ground steel from us is like buying an insurance policy. All the imperfections, runout and potential problems have been removed. All that remains is clean precise steel that is ready to be used.

Some knifemakers do not want flat ground steel. Others do not feel buying flat ground steel is a good value. To these knifemakers I ask that they let us know what they want. We may not have it in stock today, but we will have it in the future if there is enough demand.

I have bought thousands of dollars of steel from you over the years
I appreciate your many orders.

Chuck
 
All I’ll say is I’ve been happy with the magnacut I’ve ordered from New Jersey Steel Baron and Pops for 36” long bars, and if I want full 22-25”x36” sheets Niagara specialty metals. I can’t give exact prices due to forum rules, but if someone was looking for magnacut those would be my suggestions of reputable suppliers. The mill scale isn’t too bad to deal with, I’ve found runout to be negligible, plus if I need precision ground stock I’d want to do that myself so everything is the same thickness. Personally for other steels 48” long bars I’ve found to be the most ideal, the shorter 12-24” bars just create a ton of waste
 
Oh I should add since the OP is in Canada, Maritime Knife supply and Knife Maker Direct are also great sources for magnacut up north.
 
OK fellows, we are getting far away from the OP topic. Lets drop the back and forth. I do thank both of you for the info you provided. I had not noticed the OP was in Canada.

I'll sum it up:
1) Mill finish can be ground away in shaping the knife and bevels, but it takes time and belts. The bars may vary in thickness.
2) Mill finish can be removed by surface grinder - if you have access to one. You have to dial in the desired thickness.
3) Precision ground flat stock is reliably available in precise thickness and has a clean surface. AKS specializes in this. This is a good choice for most makers.
4) There are many steel suppliers. It pays to check pricing on steel from several. Be sure to compare the same grade finish and sizes.
 
Alpha Knife Supply said:
I will clarify topics brought up in previous posts.

Magnacut flat ground pricing
After my first post I searched and verified that my flat ground pricing is less than some other supplier’s mill finish pricing.

You don’t even sell full length bars
The longest billet of blade steel we sell is 35.5”. The longest flat ground piece is about 30”. There are two reasons for the length difference:
1) Longer bars will not fit on our Blanchard grinder
2) We do not have room for the additional pieces
Both problems will be resolved. When the new grinder is installed we can grind up to 60” long. When we move to our new office we will have lots more room for materials.

I’d prefer surface grinding to be an option
We are continually collecting requests from our customers. One of the advantages of being in business for more than 20 years is we have lots of data to work with. One frequent request is for precise flat ground steel.

Buying flat ground steel from us is like buying an insurance policy. All the imperfections, runout and potential problems have been removed. All that remains is clean precise steel that is ready to be used.

Some knifemakers do not want flat ground steel. Others do not feel buying flat ground steel is a good value. To these knifemakers I ask that they let us know what they want. We may not have it in stock today, but we will have it in the future if there is enough demand.

I have bought thousands of dollars of steel from you over the years
I appreciate your many orders.

Chuck
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I'm glad you are going to get some longer stock, as others said that will help save waste. I prefer minimum 36" .
4-foot is nice
 
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Joshua Fisher said:
Oh I should add since the OP is in Canada, Maritime Knife supply and Knife Maker Direct are also great sources for magnacut up north.
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Yeah I have dealt with them many times. In fact I bought one of your carbide straightening hammers from Direct.

So I managed to clean out the blades using my platen, and hand. Quite the chore due to some deeper pitting. But I managed to keep it withing reasonable thickness at a shade under .094.

So I pulled the trigger and ordered a TR Maker surface grinder. Looking forward to try that out.

I'm sure this has been discussed before, so while on the Magnacut topic, will ask here. Pros and cons with surface grinding pre and post heat treat. Thanx!
 
I hear people say less warp if you surface grind post heat treat but I thin all stock down to desired thickness before heat treat.

Post heat treat I will use surface grinder to distal taper and taper tangs, need to keep eye on temps so I use a spray bottle and constant mist of water for all post heat treat work on the surface grinder.
 
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