Author Topic: How do "They" serrate cutlery knives ?  (Read 788 times)

Offline awemawson

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How do "They" serrate cutlery knives ?
« on: November 04, 2018, 05:32:52 AM »
We have a set of  stainless steel cutlery given to us as a wedding present over 40 years ago. Over the years the knives, particularly the serrated ones, have become less stainless probably due to aggressive dish washer chemicals, and pits are forming where one of the constituents is being dissolved.

Now these aren't particularly 'special' but they do have a sentimental value, so I have had an eBay 'search' set up for the last few years for replacements of the same pattern (Jonelle Dulwich) and nothing has turned up until yesterday. A set of 6 knives, supposedly serrated, popped up, so I snapped them up, but then an apologetic seller  told me that in fact they were plain and not serrated (Tea knives not Dinner knives). I've said go ahead anyway as they are almost identical except for the serrations.

A House guest staying with us this week end said - 'well you have a work shop - serrate them' He's right of course theoretically I could, but how is it actually done commercially - I can see a home brew set up making a right mess potentially !
Andrew Mawson
East Sussex

Online John Rudd

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Re: How do "They" serrate cutlery knives ?
« Reply #1 on: November 04, 2018, 05:37:56 AM »
I guess one potential method would be to grind the "hollows" with a small radius wheel?
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Offline Jo

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Re: How do "They" serrate cutlery knives ?
« Reply #2 on: November 04, 2018, 08:54:05 AM »
I'd clamp a distance piece against the back of the knife to act as an angle guide and use a triangular diamond file - sharpening away from the blade.

Jo
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Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #4 on: November 04, 2018, 10:08:30 AM »
I'll put one on my Christmas list  :lol:

I bet those are priced to make a grown man cry !
Andrew Mawson
East Sussex

Offline Will_D

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Re: How do "They" serrate cutlery knives ?
« Reply #5 on: November 04, 2018, 12:55:18 PM »
I bet those are priced to make a grown man cry !
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Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #6 on: November 08, 2018, 11:28:22 AM »
Got the quotation back this afternoon from Germany - 175 Euros plus VAT and carriage for a 1 off, so that's not going to happen  :bugeye:
Andrew Mawson
East Sussex

Offline timby

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Re: How do "They" serrate cutlery knives ?
« Reply #7 on: November 08, 2018, 11:41:43 AM »

Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #8 on: November 08, 2018, 12:25:43 PM »
Many thanks for the link, I've just spoken to them.

Sadly they can sharpen serrated knives but not put serrations into unserrated knives  :(
Andrew Mawson
East Sussex

Online j1312v

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Re: How do "They" serrate cutlery knives ?
« Reply #9 on: November 08, 2018, 12:41:53 PM »
Andrew,

If you fancy get your hands dirty or as a last resource you can wire EDM the profile.
Also grinding may be another option.

Best,

Benardo

Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #10 on: November 08, 2018, 12:58:43 PM »
Bernardo,

I was sitting here daydreaming how I could fixture a knife held vertically in my CNC mill, with a 90 degree horizontal cutter held in the vertical spindle.

The slight curve on the profile could be accommodated in the program, stepping the spindle down 1 mm each iteration with appropriate X & Y moves.

Certainly need to make up a dummy to test it on before the live test !
Andrew Mawson
East Sussex

Offline AdeV

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Re: How do "They" serrate cutlery knives ?
« Reply #11 on: November 08, 2018, 01:03:27 PM »
Certainly need to make up a dummy to test it on before the live test !

I should think you'd want a pretty damn good fixture too! I can just imagine a freshly-sharpened 6" knife firing out of the side of your mill at high velocity....
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Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #12 on: November 08, 2018, 01:44:18 PM »
I have a box, secreted away somewhere, from when I had a horizontal mill, with a fair few odd angle cutters, hopefully something will be suitable.

I do however envision an angle plate  with a custom clamp towards the top allowing the vertical knife to rest on the mill table as a reference height, but just clamping the blade itself.

Also I'd reckon to run the spindle pretty slowly so hopefully not too many dramas  :clap:


Now where's my cache of spare time - haven't seen it in a while !
Andrew Mawson
East Sussex

Online j1312v

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Re: How do "They" serrate cutlery knives ?
« Reply #13 on: November 09, 2018, 01:48:04 PM »
You are on the right path Andrew :thumbup:,

You just need to have a nice rigid setup :poke:, the right cutter  :dremel: and some spare time :scratch:

bEst

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Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #14 on: November 09, 2018, 05:41:28 PM »
I found the box of horizontal milling cutters, and in it is a nice 90 degree cutter, but the tip radius it too large for this application. Then hunting around I found an internal threading bar with inserted tips that I think can be pressed into service. OK the gash will be 60 degrees not my estimated 90, but i'ts very shallow so I don't think that it will notice.

The bar can go in a collet held vertically and spun. I did today run a digital caliper over the curvature of the serrated bit. (Fortunately the bit of the blade opposite the serrations is a straight line to use as reference.) The width varies from 18 mm down to 9 mm at the point, with serrations every 1 mm. The Excel spread sheet that I put the data into will be the basis for a program to follow the curve cutting constant depth scallops. The blade where the serrations are is only 0.5 mm thick, and the cut is 1 mm long at 45 degrees so the cuts start deep and tail off to zero at the cutting edge.
Andrew Mawson
East Sussex

Offline hanermo

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Re: How do "They" serrate cutlery knives ?
« Reply #15 on: November 10, 2018, 03:47:06 PM »
I suspect any grinding wheel held in any mill will nicely cut serrations in any cutlery.
Like a 115 mm grinding disc for a hand held grinder.

Before you dismiss this, a major toolmaker uses 3-5 haas milling machines to make carbide tooling, and custom stuff, like this.
Youtube videos.
He says no filtration matters and in 5 years the linears wear out, in industrial production.

Offline RodW

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Re: How do "They" serrate cutlery knives ?
« Reply #16 on: November 14, 2018, 04:18:24 AM »
Hmm, I read this and immediately thought of a chainsaw sharpener I have and then found people actually used them for serrations.



This is actually a pretty cool project.
RodW
Brisbane, Australia

Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #17 on: November 14, 2018, 08:59:50 AM »
Well I've solved the problem and serrated my first knife  :ddb:

It's so simple it's silly, when you know how. You use a "Chequering File" which looks like a normal fine cut hand file, but has grooves cut along it's length, so as you gently file you leave a series of 'teeth'. Cutting wider than the file is no problem as you just locate the file in the previously cut teeth and carry on.

Pictures to follow, but I'm preparing for a dinner party so time's short (starter done, table laid, white wine chilling, red wine acclimatising  :thumbup:) - I'll do the other knives tomorrow and take pictures.

Chequering files are rare beasts, but I had a visit on Sunday from a friend who knew what they were and moreover had one of suitable pitch which I have on loan against my life as security.
« Last Edit: November 14, 2018, 11:04:43 AM by awemawson »
Andrew Mawson
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Offline Jo

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Re: How do "They" serrate cutlery knives ?
« Reply #18 on: November 14, 2018, 12:34:10 PM »
What's the difference between that and a thread file  :scratch:

Jo
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Online seadog

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Re: How do "They" serrate cutlery knives ?
« Reply #19 on: November 14, 2018, 01:02:40 PM »
The price, probably  :lol:

Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #20 on: November 15, 2018, 08:50:56 AM »
As promised, pictures of the Chequering File and the knives now serrated  :thumbup:
Andrew Mawson
East Sussex

Online John Rudd

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Re: How do "They" serrate cutlery knives ?
« Reply #21 on: November 15, 2018, 10:07:54 AM »
Well a song n dance about nowt.... :lol: Looks a mighty fine job from where I'm sitting...easy-peasy when you know how.. :dremel:
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Offline philf

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Re: How do "They" serrate cutlery knives ?
« Reply #22 on: November 15, 2018, 12:28:37 PM »
Well done Andrew,

Wash them by hand in future.

We bought some Robert Welch cutlery and were advised to hand wash the knives as they're a different grade of stainless. Either that or take them out of the dishwasher the moment the cycle has finished and dry them by hand.

Phil.
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Offline awemawson

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Re: How do "They" serrate cutlery knives ?
« Reply #23 on: November 15, 2018, 01:34:44 PM »
Phil,

In fairness to the Japanese steel maker (yes not Sheffield even then !) it has taken 45 years - or will be in December  :bugeye:
Andrew Mawson
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Offline philf

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Re: How do "They" serrate cutlery knives ?
« Reply #24 on: November 15, 2018, 01:47:43 PM »
Phil,

In fairness to the Japanese steel maker (yes not Sheffield even then !) it has taken 45 years - or will be in December  :bugeye:

We bought our Robert Welch cutlery to replace the Oneida cutlery we got when we got married (40 years in December) because the knives were pitted! The forks and spoons were fine.
Phil Fern
Location: Marple, Cheshire