Selecting wheels and cups for sharpening tool cutters

The cutting tool becomes dull during operation. This is a natural process. The quality of the metal of the cutter or saw can only affect the rate of wear, but in any case, sharpening cannot be avoided. It is for this procedure that there are special diamond grinding wheels. They are mounted on a sharpening machine or angle grinder.

The designs of sharpening discs are different, for example, there is a diamond plate, a tool in the form of a cup, just a flat disc or any other shape. All this variety of configurations is due to the goal of making it convenient to grind or sharpen various tools.

Diamond wheels are most in demand for sharpening circular saws. They are designed to work with hard pobedite tips, which are difficult for a conventional sharpening tool to handle. Let's try to understand the questions of how diamond wheels are structured, what they are, and what exactly this or that type of product is intended for.

Types of Diamond Sharpening Blades

Diamond wheels for sharpening tools have their own classification. Abrasive tool manufacturing plants produce diamond discs in three shapes:

1. In the form of a cup, it is a hollow cone inside with a metal base and a layer of diamond chips sprayed onto the working part.
2. Like a plate, where there is one-sided or two-sided recess, the profile looks semicircular-convex.
3. Discs with straight profile.

In addition, there are two main groups of tools, each of which uses a different diamond material for sharpening:

1. An abrasive made from individually created diamonds, which is characterized by high grain uniformity.
2. An abrasive made from natural diamond crystals, which are classified as technical.

And one of the most important categories that determines the purpose of a diamond disc for tool processing is the category based on the size of the bulk of the grain in the sprayed layer:

1. A fine fraction of abrasive diamond used for grinding, finishing and finishing work on material processing (100/80).
2. Medium abrasive diamond fraction used for targeted sharpening tasks, as well as for finishing grinding operations (125/100).
3. A large fraction of abrasive diamond used in rough grinding or rough abrasion of the material being processed (200/160–160/125).

In addition to all of the above, when choosing a diamond disc for a specific grinding machine, you need to take into account the diameter of the seat, the width of the working surface of the abrasive, and the base material of the tool.

2 Device for sharpening turning tools

Sharpening tools involves not only wheels, but also the use of additional devices - boring machines.

Jig boring machines bore, drill, countersink, cut internal and external threads, grind cylindrical surfaces and trim ends.

Tool sharpening machine

A distinctive feature of the machines is a horizontal (or vertical) spindle, which makes axial feed movements. The necessary tool is fixed into the spindle hole - a boring bar with a cutter, a reamer, a drill, a milling cutter, etc.

• horizontal boring;
• coordinate boring;
• diamond boring;
• vertical boring.

Specialized models of jig boring machines:

1. Jig boring machine 2D450.
2. Jig boring machine 2V440A.
3. Jig boring machine 2431.
4. Jig boring machine 2421.

2.1 Sharpening technology

1. Main back surface.
2. Auxiliary back surface.
3. Front surface.
4. The radius of curvature of the ring.

At the end, the sharpening angles are checked using a template.

Types of sharpening of cutters

To obtain an even and smooth edge, the tool must be constantly in motion along the grinding surface. With this kind of work, the circles will last longer.

The tool can be processed dry or with water. The flow of water must be sufficient and continuous. A dry tool should not be immersed in water, as this may cause destruction of the working edge.

• fine-grained whetstone (technical oil is also used);
• copper wheel (boron carbide paste and technical oil are also used).

Finishing can only be done on cutting tools (edge ​​width up to 3mm).

2.2 Safety precautions

1. Do not use grinding wheels whose operation is accompanied by beating.
2. The tool rest should be securely fixed closer to the circle.
3. Use a tool rest to support the cutter.
4. Do not press the cutter too hard (uneven heating can cause cracks; under high pressure the wheel can quickly deteriorate).
5. Do not sharpen without a protective guard.
6. Wear safety glasses.
7. The workplace must have local ventilation.

2.3 Diamond wheel for sharpening tools (video)

The effectiveness of a cutting device depends on the quality and timeliness of sharpening. The latter is due to the fact that with constant use, functional resources are lost over time. Experience over the past decade has shown that the best abrasive tool for this job is diamond sharpening wheels. They process all known types of materials, and product wear is ten times less.

Design of diamond wheels for tool sharpening

Diamond grinding discs are round-shaped products with a metal base and a coating of diamond powder applied to it, which is fixed to the metal with a binder, and there is also a filler.
The disc brand is characterized by:

• the configuration of the body and the type of material from which it is made;
• circumference size;
• the concentration of abrasive grains;
• diamond fraction;
• the type of substance used as a binder;
• degree of accuracy;
• class of imbalance.

One of the important parameters is the wear resistance of the disc.

The bodies of diamond grinding wheels can be made of steel blanks, grades St-25, 30, 20 or 3, or aluminum alloys AK-6 or D-16, or polymer materials. For some grinding wheels of type A1PP, AGC, shanks are also made from steel grades U7 and U8.

As for the binders used, which hold the diamond grains together into a single form, discs are produced based on:

1. Metallic bonds based on aluminum, copper, zinc or tin. The marking of such products indicates the letter M.
2. Ceramic bundles based on fireclay or glass, to which an aluminum component is added. The marking here will contain the letter K.
3. Organic-based binders are pulverbakelite and carbolite substances. The presence of such a link is indicated in the marking code by the letters KB.

Electrocorundum, graphite powder, copper, boron carbide and alumina are used as fillers.

Types of grain size depending on the type of processing

Grit size refers to the size of the bulk of grains among the total number of diamond particles in the abrasive.
The grain size is usually determined by three parameters: height, width and thickness, but in practice the width is taken as the basis. The surface finish of the material depends on the grain size of the sharpening wheel. This parameter also affects the efficiency of the work, the amount of metal that can be removed in one pass of the tool over the workpiece, and the wear of the working area of ​​the diamond blade for sharpening. According to the international standardization standards FEPA, the marking of a diamond sharpening tool must contain a grit code: a combination of the letter F and a certain number following it. An increasing number indicates the presence of finer grains in the abrasive. To choose the right wheel for sharpening, you need to know the grade of material, what roughness you need to achieve in the end, and the allowable allowance.

There is an inversely proportional relationship between the grain size in the abrasive and the cleanliness of the metal surface after processing. Therefore, for finishing work, grinding wheels with the smallest diamond grains are used.

The most correct approach to processing and sharpening a tool lies in the sequential use of diamond wheels, starting with the rougher ones and ending with the finishing ones. The use of only the latter can lead to burning of the treated surface, clogging and rapid failure of the grinding wheel.

Based on the size of the grain fraction, it can be classified as one or another type of grain size:

1. 100/80 – fine diamond grains. They are used to perform final finishing of thin blades, sharpening of metalworking cutters, and finishing grinding operations.
2. 125/100 – medium diamond grains. Sharpening products to the required sharpness.
3. 160/125 – large.
4. 200/160 – very large diamond grains. Abrasives are suitable for smoothing the surface of a cutting tool.

Main types of abrasive wheels

Types of abrasive wheels and basic surface treatment methods.

Let's look at the most popular ones:

• cylindrical grinding - surfaces are processed whose cross-section in a plane perpendicular to the axis of rotation is a circle;
• flat grinding - processing of any flat surfaces;
• centerless grinding - usually used at enterprises involved in processing external and internal surfaces such as, for example: camshafts, bearing races;
• abrasive wheels are used to cut and cut workpieces;
• abrasive grinding of surfaces (for example, the seat and needle of a diesel injector);
• honing - processing of round surfaces (holes) using special honing heads. Used when processing engine cylinders or
• surfaces of hydraulic pumps;
• polishing wheels - used to give the surface a low roughness and mirror shine;

Cut-off

Designed for cutting hard materials with little effort. Most often they are used in hand-held angle grinders (grinders), but can also be installed on stationary cutting devices.

They are a flat (up to several millimeters thick) disc made of abrasive material, bonded with a bond and reinforced with reinforcement.

The working edge of the disk scrapes chips from the surface of the material being processed, forming a cut. In this case, the diameter of the disk decreases, and the surface always remains ready for use, i.e. The disc is self-sharpening.

Divided by type of material processed:

• used for cutting pipes, profiles and sheet metal;
• for concrete and reinforced concrete, when cutting grooves in concrete structures;
• working with stone to give the required shape to stone and ceramic workpieces;

The variety of sizes is impressive

Grinding wheels

Used for emery. With the help of such discs, you can sharpen tools made without the use of hard alloys, as well as finishing workpieces of various shapes.

Cross-sectional grinding wheels come in the following geometric shapes:

1. Straight profile. Used for sharpening knives, axes, external and internal grinding, roughing and cleaning work. Flat grinding can be done.
2. Cone-shaped profile. Used for sharpening the teeth of non-circular saws.
3. Double-sided cone-shaped profile. They are used for finishing the profiles of shavers and cutters, gear wheels, and grinding threads.
4. Straight profile with recess, single or double sided. Used for circular, flat and internal grinding, neck and end processing.
5. Single-sided or double-sided cone-shaped recess. They are used for trimming the end with simultaneous cylindrical grinding, as well as cylindrical grinding of the neck and end.

Cup

1. Cylindrical. They are used for flat grinding with the end part and sharpening the teeth of cutting tools, for example, circular saws.
2. Conical. Used for grinding flat guides and sharpening cutting tool teeth.
3. Disc-shaped. Used for processing and sharpening multi-edge cutting tools and finishing gear teeth.

Conical grinding stones

For household sharpening machines, as a rule, universal straight profile sanding wheels are used, which can easily be changed to cup wheels if necessary to sharpen a circular saw. In general, the main advantage of abrasive wheels is their wide application possibilities.

Abrasive grinding wheels, when used correctly, require some equipment to secure the surface being processed, or at least guides.

Features of circles on organic bonds

All organic bonds cannot do without filler.
They have weak hardness, resistance to elevated temperatures and conduct heat poorly, but they are characterized by good productivity and high speed of tool sharpening operations. Diamond blades based on an organic component are purposefully used in finishing operations and when performing finishing work. They do an excellent job of sharpening pobedite materials, hard-component alloys, any metals and materials with super-hard structures. Bring the surface to be treated to levels 12 and 11 of roughness class. Discs are less susceptible to greasing, but wear out very quickly.

Recommendations!

To sharpen manicure and medical instruments, we recommend using non-diamond filler, since it is crystalline carbon and is embedded in steel at high temperatures (the chemical reaction of diamond is caricature). This process makes the workpiece brittle, resulting in chipping of the cutting edge.

It is recommended to sharpen steel cutting tools with diamond wheels based on Elbor (cubic boron nitrite). They do not cause burns.

And the most important recommendation - for diamond and CBN plates - is to use high-speed sharpening machines (2800-3200 rpm), otherwise the diamond-bearing layer will quickly become clogged.

Using our advice, you can choose the right diamond tool for yourself, saving your time and money.

Profiles on ceramic bonds

Diamond-nickel coating is used in ceramic bonds.
This coating can be single-layer or can be applied in several layers. The thickness of the ceramic-based binder does not exceed 2/3 the size of diamond grains. Due to the fact that there is a free gap between the tops of the crystals and the bond, chips removed from the surface being processed are automatically removed without creating additional obstacles to the sharpening process. Main properties of ceramic bonded grinding wheels:

• excellent ability to remove a layer of metal during sharpening;
• the ability to create abrasive tools of any configuration;
• high heat conductivity;
• acceptable cost of products.

Characteristics and features of diamond wheels for sharpening cutters

Diamond wheels for sharpening lathe cutters and other cutting tools, depending on the profile shape and type of abrasive, are specifically suitable for the following operations:

1. With the shape of a straight flat profile of grade 1A1 - for processing cylindrical products, flat parts and sharpening cutters made of hard structure alloys.
2. With the shape of a disc profile 12A2-20* - for sharpening the front part of a tool that has many blades made of hard structure alloys, cutters consisting of assembly units or all-metal, worm-type cutters, circular saws.
3. With cup profile shape 12A2-45* - for working with the back and front surfaces of carbide cutters and grinding ends.
4. With the shape of a 12R4 disc profile - for carrying out finishing and sharpening operations, as is the case with a 12A2-20* disc.
5. With a straight flat profile shape and grooves of grade 9A3 arranged on both sides - for working with cutters made of hard alloys, structural elements of machines, semiconductor structure materials, and measuring tools.
6. With the shape of a flat convex-semicircular profile of grade 1FF1 - for sharpening and grinding products made of hard alloys.
7. With a flat conical profile on both sides for working with shaped surfaces and threads.

It should be said about the concentration of the diamond component, which has an impact on the sharpening mode. With a 100% performance, the wheels have high productivity and are able to withstand harsh processing conditions without being subject to deformation. With a 50% indicator, discs are most often used for any type of work. At 20% - finishing wheels for manual tool feeding.

What characteristics are indicated on the grinding wheel?

• Abbreviation of the manufacturer.
• The material from which the abrasive wheel is made.

The grain size (roughness) of the abrasive material is in accordance with GOST R 52381-2005 or FEPA (ISO 8486) according to the European certification system. Marked within a very wide range. The finest grain F220 corresponds to a size of 50 microns. Average grain F46 – 400 microns. Large F4 is measured in millimeters.

The hardness of the grinding wheel according to GOST R 52587-2006, that is, the ability of the grain to be held together. Has mutually exclusive properties. Such a disk wears out less, but heats up the workpiece greatly, up to the so-called. "burns".

Soft - gentle on the material, but quickly loses its shape and requires frequent editing. Wheels are classified according to hardness using the Latin alphabet, in ascending order:

1. F, G, H, I, J – soft
2. K, L, M, N – medium
3. O, P, Q, R, S – solid
4. T, U, V, W, X, Y, Z – very hard

Structure of the material (density of the abrasive relative to the volume of the wheel). The higher the value, the lower the density and, accordingly, the heat dissipation. Not always indicated.

1. 0, 1, 2, 3, 4 density 68-54%
2. 5, 6, 7, 8 density 53-48%
3. 9, 10, 11, 12 density 44-38%
4. 13, 14 and more density 36-34% and less

Main types of ligament material. In fact, there are many more binding materials, but no more than three are used in the mass production of abrasive wheels.

1. V – ceramic bond
2. B – bakelite bond
3. R – vulcanite bond

Geometric circle shape . For example: PP - straight profile, PVK - with a conical groove, ChK - cup conical. The circle shape is obvious, so this type of marking is not that significant.

The manufacturer can also indicate the geometric dimensions, where the diameter of the mounting hole is especially important, and the maximum rotation speed of the wheel.

About the types and types of creative circles in detail in this video

- How do you sharpen your knives? - I have diamond bars! - Ah, you probably don’t know that they are not suitable for every knife...

(From a conversation with a blacksmith)

Quickly correct the sharpening of a knife while hunting or fishing, or sharpen the cutting edge on a newly made or completely ruined knife - with the help of a diamond stone you can do this easily and simply. Only two conditions...

• You have chosen the right diamond stone for your tasks.
• And he mastered the basic techniques of straightening and sharpening on diamonds.

Let's talk about this. The article will not contain any complex terms and concepts, for example, “deposition of diamond abrasive powder on the steel surface of a bar using an epoxy compound” or “holding diamonds using electrolytically deposited nickel”)). No, I'm not talking about that today.

The purpose of this material is to teach you how to choose a diamond stone to suit your needs and use it if necessary.

And to make our conversation easier, watch the comic video that we specially filmed for this purpose. Yes, this video is about diamond bars.

VIDEO: Diamond bars. The main thing is not to get carried away))

Well, now let's continue. What is a “diamond block”? Typically, this is a plastic or aluminum base on which two metal plates are fixed, on which abrasive diamond grains are planted and held using chemical methods.

Read also: Welding with a tungsten electrode without gas

Rice. 1 Structure of a double-sided diamond whetstone for sharpening and dressing knives

The great advantage of diamond whetstones is that even a “seasoned” whetstone that has seen dozens of knives remains absolutely flat. “What other advantages do these bars have?” you ask.

Diamond bars: advantages

• Diamond abrasive grains have sharper edges compared to other abrasives and do not change their shape during operation.
• Diamond stones are not brittle; they will not break under impact, like natural or artificial sharpening stones.
• Sharpening with diamond stones does not require special oil - just lightly moisten it with water.
• The diamond block will not become clogged when sharpening with particles of the knife being processed. To clean the bar, just rinse it in water and wipe dry with a rag or fiber.
• Diamond whetstones grind down steel very quickly. This allows you to preserve the working surface (length) of the bar for a longer time compared to ceramics or natural abrasives.

But don’t rush to run to the store or surf the Internet to buy a diamond stone. These bars have two disadvantages that may be important to you:

Diamond bars: disadvantages

• Effective grinding of knife steel during sharpening on diamond stones can lead to irreparable damage to the blade in inept hands.
• And the second drawback is the “price”. Yes, diamond stones are somewhat expensive compared to natural abrasives, since the technology for producing good (read branded) diamond stones is quite expensive. And prices usually start at 800 rubles (11/02/2016). Have you seen it cheaper? Avoid this block! After 5-10 sharpenings it will be bald - you’ll have to throw it away, but you don’t want that, do you?

We’ll fix your hands now)) – more on that below. And the second drawback, “price,” is more problematic to correct. Everything is in your hands here. Sorry for the pun.

Diamond bars: designation and marking

But first, let's learn how to choose a diamond stone. Have you seen their designation? Look: 2500/2000, 2000/1600, 1600/1250, 1250/1000, 1000/80, 800/630, 630/500, 500/400, 400/351, 315/250, 250/200, 200/160, 160/125, 125/100, 100/80, 80/63, 63/50, 50/40, 40/28, 28/20, 20/14, 14/10, 10/7, 7/5, 5/ 3, 1/0.

Confused? Nothing complicated really. These designations are adopted according to GOST 9206-81 (diamonds) and are divided into:

• 12345 — Diamond bars for repair work associated with intensive metal removal, namely, restoration and change in the shape and profile of the blade and cutting edge.
• 12345 — Diamond bars for removing traces of roughing operations, grinding and basic sharpening work, namely obtaining the specified parameters of the blade and cutting edge.
• 12345 — Diamond bars for removing grinding from the blade surface, finishing sharpening and finishing of cutting tools.
• 12345 — Diamond stones for straightening cutting edges and polishing surfaces.

Now fine? And the marking is deciphered as follows, for example, “125/100” means that on this side of the bar there are diamond grains of at least 100, maximum 125 microns.

Usually, the manufacturer puts a mark on the bars (on both sides), which indicates its grain size. Like this:

Rice. 2 Diamond stone marking

Considering that we are talking about double-sided diamond bars, you understand that one side is intended for rougher sharpening operations, the other for straightening and polishing the cutting edge.

"Cool! One diamond block for two operations! - you exclaim.

Yes, that’s right, “two in one”. As a rule, the greenish side of the bar is rougher, and the brown side is thinner. If there is no marking, you can feel it tactilely with your fingernail, or take a magnifying glass and feel it visually.

Universal diamond stone

Now, listen to the advice of experienced people. A diamond block with one side marked “100/80” and the other “50/40” covers 99% of sharpening operations. Believe me, this bar will be enough!

Do you have little experience in sharpening operations or is there no need to sharpen the cutting edge before planing the hair? Buy this particular block! He will always be with you. Put it in your backpack when going “out into nature”, take it with you when hunting and fishing – a universal diamond whetstone will give sharpness to your knife while cutting up a wild boar carcass, a rich catch, or when slicing food in the kitchen.

Do you make your own knives? Or is sharpening knives your hobby? Use our “Abrasives Table” to select diamond or other stones to suit your needs.

Rice. 3 The table of abrasives will help you navigate when choosing a sharpening material to suit your needs

Download it in high resolution from this link.

How to sharpen with diamond stones?

We have more or less figured out the choice of diamond stone. If anything, write to me by email. I'll help you with advice. Let’s start “editing our hands,” namely, competent sharpening on diamond stones. The rules here are simple and strict. I'll list everything at once:

• Before sharpening, wet the diamond stone with water. You can put a drop of detergent on the bar, for example, Fairy (not advertising).
• During the sharpening process, after every 15-20 movements, wash off the resulting emulsion from the block under running water and continue.
• Tired? Decided to have a smoke break? Place the block in a bowl of water for a while.
• When you sharpen a knife, do not hold the block in your hands. It is better to place it on a wooden plank with a slight stop so that the block does not slide on it.
• It is allowed to hold the block in your hand when editing a knife in field conditions. But watch your fingers! Even if your knife becomes dull, it will still be able to cause severe cuts to your fingers.
• When sharpening, try to use the entire surface of the block, rather than sharpening the knife along one edge or in the middle of the block. In this case, the diamond layer on the block will be ground down evenly.
• There is no need to press hard on the knife during the sharpening process - this is perhaps the most important rule! With strong pressure, you will break out abrasive crystals from the surface of the stone, which is not very good. And you can simply ruin an expensive diamond block.
• The last rule is most relevant for a new (newly acquired) diamond stone, which you first have to “break in” or grind in.
• Remember that a new diamond stone will initially remove steel more aggressively, but will begin to lose that aggressiveness with each knife sharpened. This is normal. After sharpening 5-10 knives, the diamond bar will reach its intended condition and will serve and delight you for many years.

Read also: Soldering stainless steel with copper-phosphorus solder

Now let's start practicing. I won’t talk about how to initially mark the cutting edge on a newly made knife. A lot has been written about this on various knife forms. And there are special devices. But if you have come to this, then most likely you already understand sharpening with diamond and other stones.

And if you are just learning the basics, then a video on how to correct the sharpening of a knife on a diamond whetstone will be useful for you. Look:

VIDEO: Dressing a knife on a diamond stone

Where to buy double-sided diamond stones?

Did you like the article? Did you get anything useful from it?

Let's move on to shopping! Here is a link to the section of the online store where diamond stones are sold. And not just any stones, but diamond stones of good quality (branded, branded) and from a Russian manufacturer. All of them have been tested not only by us, but also by hundreds of buyers who have never expressed a negative opinion about them. Read the reviews on these product pages:

Diamond whetstones in the online store Zlatoust knives

PS Did you notice that there are two sizes of diamond stones? 200x35x10 and 120x35x10 . Personally, I recommend taking a larger size. Why? It's just more convenient to sharpen! Small bars are more convenient to take with you on a hike or hunting due to their light weight and size. And if you sharpen at home, then doing it on a large block is more comfortable.

PSS Do you remember the excerpt from the conversation with the blacksmith at the beginning of the article? So, knowledgeable people do not recommend using diamond stones for sharpening and straightening knives made of cast damask steel.

This is due to the fact that... (I’ll write soon).

Feel free to sharpen knives made of other steels on diamonds! Good luck!

Leather belt for straightening Spannstreichriemen Böker, Germany

Double-sided bovine leather tension belt for final edge dressing

Blank 25 mm wide for sharpening stones (for Apex type machines), Russia

Wide stone blank, for use in Apex sharpening systems

Suede polishing block, for Apex V type machines >

Suede block for polishing pastes

Leather polishing block, for Apex V type machines >

Leather block for polishing pastes

Blade Grinding Attachment for Knife & Tool Sharpener Ken Onion Edition Work Sharp, USA

Knife & Tool Sharpener Ken Onion Edition attachment makes work easier and faster

Set of sanding belts (of 6 pcs.) for electric machines Sharp Knife & Tool Sharpener Work Sharp, USA

Set of abrasive belts of different grit levels

Sanding belts P80 (6 pcs.) for electric machines Sharp Knife & Tool Sharpener Work Sharp, USA

Set of coarse abrasive belts

Sanding belts P220 (6 pcs.) for electric machines Sharp Knife & Tool Sharpener Work Sharp, USA

Set of medium grit sanding belts

Sanding belts P6000 (6 pcs.) for electric machines Sharp Knife & Tool Sharpener Work Sharp, USA

Replaceable fine grit abrasive belts

Sanding belt set (P120,X65,X22,X4,12000) for Work Sharp Knife & Tool Sharpener Ken Onion Edition, USA

For correcting the cutting edge, sharpening and final finishing of any cutting tool

Sanding belt P120 for electric machines Sharp Knife & Tool Sharpener Work Sharp, USA

High quality coarse sanding belt

Diamond sanding belt P180 for electric machines Sharp Knife & Tool Sharpener Work Sharp, USA

Coarse diamond grinding belt for sharpening ceramic knives

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What to look for when choosing a diamond blade

The convenience and speed of working on a sharpening machine directly depends on the correct choice of diamond blade. In some cases, the wrong choice can cause deformation of the disc or damage to the cutter. Here's what you need to analyze before choosing a specific drive:

• the grade of metal that will be sharpened or the type of carbide;
• revolutions and power of the sharpening machine;
• shape of the surface being treated;
• degree of permissible roughness.

The diamond blade you purchase must strictly comply with all these parameters.

If you are a professional who works with turning equipment or someone who has experience using diamond grinding wheels, take part in the discussion of the topic in the comments. Expert knowledge is always valuable!