Badger’s Bum Trials

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Badger’s Bum Trials

This topic has 14 replies, 5 voices, and was last updated 29 May 2011 at 13:32 by chris stephens.

Viewing 15 posts - 1 through 15 (of 15 total)

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28 May 2011 at 20:54 #69283

Hugh Gilhespie

Participant

@hughgilhespie56163

Inspired by Andew’s and mgj’s postings I did my own trials. Where possible I used identical conditions to those used by Andrew for a comparison. So, excuse my plagiarism and herewith the result. Photos (not very good) are in my Badger’s Bum album.

Lathe: Colchester Student 1800, running from an inverter supply.

Workholding: Burnerd Multi-size collet chuck

Material: 1.375″ diameter steel – horrible old gas or water pipe, probably galvanised.

Depth of Cut: 40 thou, ie, 80 thou off the diameter.

Feed: 4 thou per rev.

Coolant: Rocol Multisol, 20:1 Dilution

Tool Tips: I used two different inserts and M42 HSS tangential tool.

The inserts were:

Korloy	CCMT09	Grade NC3120	0.2 mm tip radius
Sumitomo	CCGT09	Grade T1200A	0.2 mm tip radius

The tangential tool is the Oz version from Eccentric Engineering. I gave it a quick sharpen and a slight radius.

The Sumitomo inserts are the Titanium Carbide grade that is claimed to be effective at much lower surface speeds than nor

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28 May 2011 at 20:54 #29437

Hugh Gilhespie

Participant

@hughgilhespie56163

28 May 2011 at 20:57 #69284

Hugh Gilhespie

Participant

@hughgilhespie56163

Useless site!! More –

The Sumitomo inserts are the Titanium Carbide grade that is claimed to be effective at much lower surface speeds than normal Tungsten Carbide.

The trials were:

1: Korloy, 230 rpm (83 sfm) with flood coolant

2: Korloy, 230 rpm (83 sfm), dry

3: Korloy, 1800 rpm (648 sfm) with flood coolant

4: Korloy, 1800 rpm (648 sfm), dry

5: Sumitomo, 305 rpm (110 sfm) with flood coolant

6: Sumitomo, 305 rpm (110 sfm), dry

7: Sumitomo, 1800 rpm (648 sfm) with flood coolant

8: Sumitomo, 1800 rpm (648 sfm), dry

9: M42 HSS, 230 rpm (83 sfm) with flood coolant

10: M42 HSS, 230 rpm (83 sfm), dry

As the results with this were – err badger’s bum – I tried progressively reducing the depth of cut from 40 to 20 then 10 thou.

11: M42 HSS, 94 rpm (34 sfm), dry

The results were

Trial 1

Korloy

230

rpm

Coolant

28 May 2011 at 20:58 #69285

Hugh Gilhespie

Participant

@hughgilhespie56163

More 2

The results were

Trial 1

Korloy

230

rpm

Coolant

General Appearance

Badgers bum.

28 May 2011 at 21:00 #69286

Anonymous

Oh, b****r, and I’ve just spent an evening doing more trials on different materials, only to be beaten to publication!

Mind you the evening hasn’t been entirely wasted, as the CNC mill has been whirring away in the background making another prototype bevel gear pinion for my traction engine.

Regards,

Andrew

28 May 2011 at 21:31 #69287

Hugh Gilhespie

Participant

@hughgilhespie56163

More 3 – After reformatting

The results were

1 to 4 Korloy

1: Badgers bum, rough appearance, rough feel. Small swarf, no oxide colour

2: Similar to 1. Slightly rougher. Very small chips, dark blue

3: Much better than 1 & 2. Smooth to touch but fine scoring felt with nail.

Small chips, gold colour.

4: Better than 3, feels smoother. Scoring as 3. Small chips, very dark gold.

5-8 Sumitomo

5: Best overall finish. Very smooth and no scoring although slightly more matt finish.

Small chips, no oxide colour.

6: Brighter than 5 but feels rougher and more scoring. Small chips, dark straw colour.

7: Very similar to 5, smooth to touch, very fine scoring. Long spirals, dark straw colour.

8: Better than 7, smooth and brighter. Same amount of scoring. Long spirals, very dark blue/straw colour.

9-11 M42 HSS

9: Matt finish, rough to touch, worst so far. Long spirals, no colour.

10. Rough, slightly shinier than 9. Gets slightly smoother with INCREASING depth of cut. Long spirals, no colour.

11: Best of the HSS finishes, smooth to touch but scratchy to fingernail. Long spirals, no colour.

Overall it was clear that the Sumitomo inserts gave the best results. I don’t have enough experience to know if the finishes I got were good, bad or indifferent but at least I could see – and feel – the difference. I was a bit surprised that the HSS results were not particularly good as I found when cutting 303 grade stainless that the tangential tool gave an excellent finish. Not having a surface roughness meter, the only criteria I could use was feel and appearance. Interesting that even where the surfaces of Trials 3 and 4 felt smooth to the fingertip, they still felt rough running my fingernail along them Not so with the Sumitomo finishes even though the surface had a more matt appearance.

If I get the energy, I will carry on and try a selection of tests on some ‘proper’ EN1A to see if this gives such a noticeable range of results. I would also like to compare how easy it is to make very fine cuts – say about 1 thou.

Regards, Hugh

28 May 2011 at 21:39 #69289

Hugh Gilhespie

Participant

@hughgilhespie56163

More 4- More of an apology really, I think I should devote more time to learning how to post instaed of playing with machines!

Andrew – I for one am looking forward to your next installment.

Regards, Hugh

28 May 2011 at 22:16 #69291

Anonymous

We could say that the formatting is badgered; must be using the wrong speeds and feeds.

Regards,

Andrew

29 May 2011 at 00:48 #69295

chris stephens

Participant

@chrisstephens63393

Hi Guys,

I will wholeheartedly concur re Sumitomo tips, their T1200a “cermet” are the muts nuts and Giraffes gonads too.

The finish that can be achieved is almost as though the metal had been polished and chromed. There is a caveat, if they

are used in a cavalier fashion they will chip very easily as they are extremely brittle, but with correct use they will last well.

I hope that Arc will decide to stock the right grades and chip breakers, now that they have decided to retail Sumitomo.

christephens

29 May 2011 at 09:41 #69297

mgj

Participant

@mgj

Thanks for that- I have long colums of print and an invitation to ignore or restore members? Apart form that!! its an excelelnt post.

Clealry Sumitomo are better in htis instance, and better wet at all speeds – and that speed isn everything. Buto f course that doesn’t mean to say that would be true for all materials.

What isclear is there is a difference between tips, I love SECO, but when I next buy some I will try these Sumitomo jobs – though I was looking faround Ebay for APKT milling tips, and see that ISCAR are sellincg CCMT0602 04 tips very cheaply. SECO wil chip too , but one is dealing with a brittle sintered material and that can happen.

There is probalby a great deal of difference between HSS – some being good, some being bad. Some being well ground, and some not. I will post a pic of what I reckon an HSS knife tool should look like a bit later.

Incidentally, one of the advantages of tipped (indexable) tooling which no one mentions is the shape of the holder. The cutting tip is alway clear of the shank so you never have to adjust the toolpost angle – you can set it square and swap between a knife or parting tool without any changes in set up. And it will face across any size of disc without fouling.

Chris – you got squished too!

Edited By mgj on 29/05/2011 09:47:41

Edited By mgj on 29/05/2011 09:48:42

29 May 2011 at 10:37 #69298

Ian S C

Participant

@iansc

Hi Hugh, all I can say is that you’v done well with galvanized water pipe, its a pig of a stuff to get a good finish on, although I have used it for a power cylinder on a large (2″ boer) hot air engine. The only problem I had was that just as I got the bore nearly true the weld let go and the pipe opened upabout 6 mm. I closed it up and welded it, then finished the cylinder, its still works OK, it took a while honing then lappingto get a good finish, it runs with a cast iron piston, with next to no lubrication. Ian S C

29 May 2011 at 10:49 #69300

Anonymous

A small point; I’ve found that the finger nail is an excellent comparative tool for surface roughness. It is possible to tell the difference between surfaces that vary by rather less than 1µm

Ra.

Regards,

Andrew

29 May 2011 at 12:44 #69314

chris stephens

Participant

@chrisstephens63393

Hi MGJ,

I have put a link to the Sumitomo catalogue, as you will no doubt know there are a myriad

of different tips to choose from. Personally I prefer “positive” tips ( it’s much easier to make holders that have horizontal seats for the tips) and a “finishing” or “fine finishing” chip breaker. Speaking of which, close scrutiny of the little graphs showing the chip breaker characteristics will be worth the effort, most enlightening.

When selecting one tip for a very large selection one has to be careful to pick the one that serves your purpose best. It should also be remembered that just because a manufacture produces some particularly good tips, it does not mean that every tip they produce is good, for your use. A rough milling tip will NOT produce a mirror finish when used for finish turning, and this I feel is the problem with buying surplus industrial tips, you have no idea what they are designed to do.

http://www.sumicarbide.com/pdf/turn/TB_insert_cc.pdf

chriStephens

PS what’s with the new post layout?

PPS I think that triangular tips are better value than rhomboid ones, three good points compared to two good ones and two (near) useless ones.

Edited By chris stephens on 29/05/2011 12:47:46

29 May 2011 at 13:17 #69317

mgj

Participant

@mgj

agreed.

Its like GTN tips. They are a negative rake parting tip. Dimensionally and in the catalogues they are interchangeable with GFNs – they look so similar. In fact the difference being that the GFNs are positve rake, whihc is a huge difference in characteristic.

If you look at SECOs on line cataloge they list in CCMT -06 30-40 different tips. Iscar about the same

Tips are a bit of a minefield!

29 May 2011 at 13:32 #69318

chris stephens

Participant

@chrisstephens63393

And I bet you know a few EOD personnel to help?

chriStephens

Viewing 15 posts - 1 through 15 (of 15 total)