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Getting started tool resharpening

burnthesky

Plastic
Joined
Nov 4, 2023
So I'm looking into starting up a small tool sharpening "side hustle". I work as a machinist now and I've talked my boss into giving me a shot at taking over our tool resharpening. Assuming I can match or improve the current quality of our resharps.

So it would be CEM's and HSS drill bits.

I'm trying to figure out what I should start with. I was looking at the Cuttermaster JXT for the endmills and Darex for the drill bits.
But i really have no idea where to start. Just looking for some good advice or opinions. Is there something better? Am I an idiot for thinking I can do this? Also I need to be able to set it up in a garage without any extra electrical work.
 
When I was a kid in college my dad ran the stores operation for the phone company in Birmingham, UK. "The Post Office".
Anyway, it used to bug him that so many of the tools the linemen used were scrapped when they were worn. So he did a deal with me where I would sharpen drill bits, screwdrivers, wood chisels, cold chisels etc by hand, for half the cost of new.
Also used to put new handles in hammers and axes.
Put the new handle backwards into an axe once - kept that one for myself.
All done by hand on a simple grinder.
For the screw drivers I put a white wheel in a drill press, set the table over to the angle, held the screw driver in a vice, and swung the table under the white wheel.
Made some pretty good money, for a kid.
Bob.
 
Hi burnthesky:
Cutter grinding has become one of those skills that is almost obsolete because the cost of a new cutter has become so inexpensive and because the widespread adoption of CNC has made it unnecessary to make as many specials as were necessary when everything was still done on manual machines.

So many modern shops never sharpen anything and just replace it when it's no longer serviceable.
It's cheaper for them to do it that way...at least that's the common wisdom.

So getting into cutter grinding as a side hustle may not pan out for you in 2023, whereas it was a perfectly viable business in the 1970's when I grew up in the trade.

However, if you do want to get into it, I'd look for two specific machines:
1) a Darex SP2500 drill grinder.
They are an obsolete model but are quick and accurate.
They cost about a thousand bucks if you can find one used on EBay...that's where I got mine.
I can grind a 1/4" drill in about a minute from when I turn the grinder on to where I turn it back off (yes, I've timed it when a colleague called bullshit on my claim.)

2) For general cutter grinding something like a Cincinnatti #2 or one of the many clones that are out there.
Alternatively, a Deckel S1, or if you're made of money, a Deckel S11 or a Christen AU150.
If you hope to do flute grinding on milling cutters, the Christen style workhead is super useful because it doesn't rely on a finger rest and air spindle to rotate the cutter past the wheel...there is a sine bar bar mechanism in it that you can adjust to get the helix angle right.

Be aware also that for any air spindle type flute grinder you will need a compressor, and it needs to be a decent sized one because air spindles are air hogs.
This gets to be a problem as soon as your business is in a residential area and your compressor is hammering away of an evening, pissing off all your neighbours.
You might have to spring for a screw compressor if you want to stay under the radar.
Last one I bought was ten grand Canadian but that was back in 2016.

Also, the Christen and the Deckel will be 3 phase machines as will a Cincinnatti or its clones, so you'll need a phase converter and some juice...I have 400 amps to run 9 machines in my shop.

That Cuttermaster JXT looks to be an OK machine from what I can see on the website, but I do have a criticism.
The wheel elevating mechanism looks unshielded...that's not gonna survive very long with carbide dust flying around before it's totally worn out.

Also, it's gonna get real old real quick to be setting up and tearing down the machine constantly as you switch from flute grinding to end flute gashing.
For 5 grand (the cost of that Cuttermaster) you can buy yourself 3 or more used EBay grinders and set each of them up to do one specific task.
You'll spend no more money, and if you choose well, you'll get better grinders that you can run far more efficiently.

Last, carbide dust is not good for you...it's got cobalt in it, which is toxic.
Necking a cutter occasionally won't do you much harm, but swimming in it all day every day will fuck you up eventually.
So you need dust control...two ways to achieve that:
1) coolant
2) a Torit or other vacuum system.

So much to ponder...it's not quite as simple as just dropping a couple of machines on the bench and going to town.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
I ageee with Just Dave and Marcus, Most of the youtubes are very short sighted.
Dont use the term CEM's but use the real name for things.
The Cincinnati manual on vintage machenery is the newer version so almost worthless. I tried to sent them the older version but the Email woud not go.

Grinding drill points (ends), end mill ends, and making a needed specials are things a handy fellow can do to make a simple TC grinder worth its floor space.
Grinding end mill ODs as one-ups are not worth the time.
Having a TC geinder it is good to mount a vice and a parting wheel so at not-use tims it becomes a cut-off machine.
A skilled tool sharpening hand is a valuable asset to a shop but he has to be able to sharpen a tool in less than 10 minuets and make a special in under a half hout to earn his salt..
A skilled Tc grinder hand can save a shop a ton of money with a simple conventional Tc grinder, but most likely would need a ton of experiance.
 
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Hi Michiganbuck:
I'd be really curious to see how that endmill cuts with that horrible undressed diamond wheel having gnawed at it and beaten it to ratshit.
As you've pointed out, it doesn't sound good, and my diagnosis is that the guy running the machine just popped on a 150 grit diamond wheel straight from the box without putting a brake dresser to it after it was mounted.

Frankly I'm kinda surprised Cuttermaster let that video out into the world.

I am unimpressed and it sounds like you are too.
That's not to say the grinder is no good...it's the lack of finesse in its use.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
How much of manual tool grinding do you know?
It takes a while.
Just for starters the 6 basic drill points, notching, etc.
Variable flute and variable helix end mills are common now.
Buck used to link to a manual for I believe the small Cincinnati, As he said you want the old version.
There is also one for the ancient LeBlond tool and cutter grinder that has lots of set-up info.
You can run the older tool and cutter grinders which are 3-phase off of a VFD on single phase as the spindle motors are very small.
Shop vacs can be used grinding carbide but a much quieter and easy to live with solution is an old furnace blower with a filter or two up front and do it yourself ductwork.
I have even made the ducting and box here out of drier vent tube, cardboard, and duct tape.
You will not get rich here but if you enjoy doing it and want some side money.....
How would you shop pay you? Cash, 1099, your own company name? Think about that your rich uncle Sam may want a cut here.
Who knows? Might grow into a bigger shop, handful of employees, a new cnc Walters......

Also not mentioned here is inspection equipment to check your work. This can get expensive.
Bob
 
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Thanks guys lots of good info here.
I'm definitely not trying to get rich here. Or do it full time. I have an addiction to buying new tools. And tools are expensive so I was just looking for a little bit of disposable income to support my addiction.

I don't have alot of experience tool grinding. Very little in fact. I can hand grind drill points. And I've been "perfecting" my technique on countersinks and spot drills.

Also I do realize this is probably a bit ambitious of an undertaking for a few bucks on the side.

I've seen what we pay for resharps and definitely think the opportunity is there as long as I can make a good product.

We use our carbide endmills almost exclusively for finishing diameters. So flute sharpening is the biggest thing. And we use 3/8 to 1" carbide end mills. I beleive they are variable helix as well.

I would really prefer a tabletop machine which is why I was looking hard at the JXT. But I am a bit worried about the grind quality. Although I think with practice and maybe some customization that could be worked out.

Could you set up a small lathe to do it? I'm guessing that would be a decent project.

As far as the drills I was thinking of finding a used Darex v390. We have one at work that pretty much no one uses but me and I've found it works really well and is pretty consistent as well as does a nice split point.

I can do it by hand pretty well. But not sure how consistent I can keep up if I'm cranking out 100-200 drills.
 
Hi again burnthesky:
Yeah, I'd worry about the grind quality too on several fronts:
1) The spindle bearings matter and on a direct drive machine like this one you will get only as good as the motor bearings which may or may not be good enough.

2) The evenness of the end flutes you grind depends on how well you snug the end float "collars" up against the air spindle housing and how smooth and square the end faces of the housings are and how much or little runout the collars have.
It's a cheapass way to press an air spindle into a service it was not designed for and I'm suspicious of it...I don't think you're going to be able to do good consistent end flutes with it unless the machine is very accurately built.

3) Like with a cylindrical grinder, the cross feed screw that moves the cutter toward and away from the wheel needs to be fine pitch if you hope to be able to control the cutter diameter accurately.
On a resharpened cutter it may not matter that much, but on a special it will, if you hope to hit the desired diameter with any consistency.

4) Grinders do better when they have some mass...I have a home built desktop cutter grinder, and it's too light (300 lbs) to be as smooth as my 2000 lb surface grinder.
It does pretty well but not as well as it would if it was 3 times the mass.
DSCN5760.JPG
A lightweight grinder is exquisitely sensitive to the smallest bump...just touching it wrong puts a small gouge in your workpiece, and on a cutter it shows up like a wart on a princess.

If you want to run a serious grinder, find a proper floor model cutter grinder in good condition.
There are lots of good brands out there and many of them have seen very little use, are well tooled and are available for cheap because nobody values them anymore.
Guys like michiganbuck, eKretz, cabide bob and others with a ton of grinder experience can chime in here with brand recommendations...I'm not sure a Cuttermaster will be on the top of any of their lists... not for over 5 grand:eek:

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
No way. Get a used #2 or something. You can do everything on that. And they really aren't that expensive if you do some looking.. you have a lot to learn if you want to get up to top speed. And if you can beat the CNC grinders at any real quantity, you're better than me.
 
No way. Get a used #2 or something. You can do everything on that. And they really aren't that expensive if you do some looking.. you have a lot to learn if you want to get up to top speed. And if you can beat the CNC grinders at any real quantity, you're better than me.
Won't I need 3 phase for that?
 
Hi again burnthesky:
Nope, you need a phase converter...even if you just cobble one together from an old 3 phase motor and a pull string like I ran for years.
Grinders don't have big spindle motors so they don't need much.
If you really want to go Cadillac for no good reason other than to spend money, you can spring for a Phase Perfect, but since you're not planning to run a whole 3 phase shop you can just run a Rotary Phase Converter (which is basically a 3 phase motor with start capacitors).
Plug it into the Lovely Wife's dryer circuit or range circuit and you'll be fine.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
Thanks guys lots of good info here.
I'm definitely not trying to get rich here. Or do it full time. I have an addiction to buying new tools. And tools are expensive so I was just looking for a little bit of disposable income to support my addiction.
I hear you there, same problem here :) How about this for an alternative - buy used tools at auction and resell them. Cutting tools, measuring tools, even material, anything that can safely fit in a flat rate box. Sort, clean, throw out the crap (or give it away), put it into lots that hobby or small shop machinists find useful and sell it on here or eBay. As long as you keep a lid on the auction bids you place (ha! I should talk) you can make some comfortable side money doing so AND you get to keep various bits and pieces for your own shop. No particular skill or investment in tooling required. A patient wife or landlady is a must however.
 
Do not forget the extras.
Diamond wheels $200 to $400 each and you will need several styles and grits.
Wheel adapters, collets, Tri-mics, toolmakers scope or compartor, plate, DTIs, St. Mary, etc.
Even at scrap metal prices for a Cinic 2 or its ilk you can easily have close to $10,000 invested here with needed fixtures, tooling and misc.
Have friends with such machines unused now that I could get. Still have to move it. Yes right about top weight for a lift gate Ryder truck and pallet jack on each end.
Done this for sure on the low buck. Do not recommend such if you have not done it before.
Maybe I could do the whole deal for $5000 in a squeeze. You do need those attachments.
This is not even looking at drills.
Just conical? The cinic type machines can handle the 4 facet with ease. One can split by hand with practice.
Welcome to the rabbit hole. Come on in says the mad hatter. It is a deep hole.
Overall I think you can make it work if you have a square head on your shoulders but there might be a few things that trip you up on the way.
Looks easy but it is full of small details here and there and the darn Devil lives in those details. Be prepared to fight him.

On this what happened to the Mountain Top re-sharp shop, a member here but not sure the user name.
 
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