Cheap Tools …….. Grrrrrrrr.!!!!!

[Chris DentonParticipant @chrisdenton53037]

I got through 4 angle grinders in two weeks once. Finally bought a Hitachi and it's been fine! The cheap ones are absolute rubbish.

[Roger Williams 2Participant @rogerwilliams2]

Hello all, I bought a lathe a few years ago that came with a Gepy, but it must have been abused, because the taper roller bearing was damaged . Ive stripped the thing, and the outer race looks like part of the main body, so unless it could be re-ground , with a new inner race as well, its U/S. .

[Mike PooleParticipant @mikepoole82104]

A friend of mine buys cheap power tools for site work as expensive ones get stolen before they wear out,if he breaks the tool they are guaranteed so he gets a years use at least and if it gets stolen it's not the end of the world.

Mike

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 08/12/2014 17:59:09:

But is the Gepy a slim body, looks to me like a standard sort of dia body …

.

Jason,

For info. Here is the Gepy version of slim:

Pictured alogside his lovely female companion.

I bought these two "pre-loved" at least 25 years ago.

I had hoped that they would be a breeding pair … so that I might get rich, selling the puppies

… but no joy so far.

MichaelG.

[JasonBModerator @jasonb]

Thanks Michael, looks like it gives a bit more tool clearance but the toolpost can still hit the larger dia bearing/body. I prefer to have an extended tool holder on Dickson and use my usual Skoda ctr.

J

PS I never had problems getting Guppies to breed

Edited By JasonB on 09/12/2014 19:29:57

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 09/12/2014 19:29:27:

PS I never had problems getting Guppies to breed

.

Brilliant response

MichaelG.

[Robin GrahamParticipant @robingraham42208]

Go on. – Tell me.! ……….. How many beer vouchers.?

Nick

Nick, you'e talking about 100 pint vouchers I think depending on your locality . https://shophardinge.co.uk/productGrid.aspx?catID=7943 .

I'd like one, but my tailstock is off by 12 microns anyway!

Rob.

[Michael GilliganParticipant @michaelgilligan61133]

UPDATE:

Nick kindly sent me his broken centre, and I have taken some close-up photos of the fracture [three posted here; more in my album].

I think this is best categorised as a Brittle, or Chalk Stick, fracture

There is no visible evidence of fatigue: The failure is typical of a brittle material subjected to a high unidirectional bending load.

The material has a granular structure, with some surface defects and some inclusions. … i.e. It looks more like cast iron than steel.

.

The fracture clearly originates at the edge of the narrow groove, and breaks-out diametrically opposite.

—

It is worth mentioning the surprisingly small dimensions of the component parts of this SlimBody centre.

Although the fitting is No.2MT, the major diameter of the rotating centre is just under 10mm, and its shank is only 6mm diameter. … The front bearing is a 626Z, and I presume there is another behind it.

—

In the New Year, I plan to section and polish the broken shank, for inspection under the microscope; in the hope of better identifying the material.

MichaelG.

 

 

 

 

 

Edited By Michael Gilligan on 14/12/2014 23:23:54

[Phil PParticipant @philp]

I have one of these centres and it failed in exactly the same way just like the one in the photo.

I made a new silver steel revolving part for it, but to be honest I have never got on with it since and tend to use my old J&S or Rohm ones.

[Ian S CParticipant @iansc]

It almost looks as if it was designed to fracture, the diameter must be about 5 mm at the bottom of the groove.

Ian S C

[JasonBModerator @jasonb]

I would like to know how the tip got bent (see last photo) and if this had any bearing on the fracture. You would expect that if it is an over brittle material the tip would not bend like that. Maybe when it was heat treated the thinner stem cooled quicker than the larger dia working end?

Michael, it would also be interesting if you could test the hardness at both ends

J

[Nick_GParticipant @nick_g]

Posted by JasonB on 15/12/2014 10:31:27:

I would like to know how the tip got bent (see last photo)

Ditto.!

It certainly was not there before I started turning and the rascal broke.

I was taper turning at the time of breakage using the compound slide if that helps with the investigation. Even taking into consideration when doing such the cut gets deeper as you progress the cut was quite light.

Nick

[Gordon WParticipant @gordonw]

Has it been used a lot for taper turning by offsetting the tailstock ?

[Nick_GParticipant @nick_g]

Posted by Gordon W on 15/12/2014 12:08:58:

Has it been used a lot for taper turning by offsetting the tailstock ?

Nope. Never.!

Nick

[John Stevenson 1Participant @johnstevenson1]

Michael,

Try a quick and dirty spark test to clear up whether or not this is cast iron.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Stevenson on 15/12/2014 13:12:05:

Michael,

Try a quick and dirty spark test to clear up whether or not this is cast iron.

.

O.K. … a few quick tests on the 10mm-ish body

• A good needle file will just mark the surface, but not really cut
• A scriber point will just produce a faint scratch
• Sparks from the grindstone are quite short, but white and sparkly

My preliminary conclusion is that this must therefore be a steel … despite the appearance of the fractured surface.

… Expert opinions welcome !!

MichaelG.

[Jon GibbsParticipant @jongibbs59756]

Hi Michael,

If you take a look at the Metcalfe experiment conducted here **LINK** you may get a clue to what may have happened.

In short I think it looks very much like a fracture of badly hardened steel.

HTH

Jon

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Jon Gibbs on 15/12/2014 16:24:14:

If you take a look at the Metcalfe experiment …

.

Many thanks for the link, Jon

… I will watch the videos tonight.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Jon,

Thanks again for the link

… I have watched the videos and learned a lot.

Assuming that I have understood correctly: the shank on Nick's centre was too hot prior to quenching, and was not [sufficiently] tempered after hardening. … I suspect that the heat treatment process is 'just right' for the head of the centre, and unfortunately wrong for the much smaller cross section of its shank.

Until I saw those Metcalfe results, I had no idea that steel could go so granular !

I do however remain concerned/confused by the surface defects, and the [graphite?] inclusions visible in these two photos:

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Note:

There is a small white hair visible in the upper left quarter of that second photo; but I thought the black lines were graphite inclusions. [getting worried now] … Might not be certain until I section it.

MichaelG.

[MEinThailandParticipant @meinthailand]

Posted by SteveW on 08/12/2014 08:24:21:

Nothing wrong with inexpensive but cheap is a different matter! I find inexpensive tools from the 'usual suppliers' generally OK; some of the 'best' are just too expensive for my budget.

SteveW

I am getting pretty fed up with the poor quality of tools from the "usual suppliers". it seems that all the focus is on price and hang the quality. I guess model engineers have brought this on themselves by always looking for the cheapest.

All these tools were purchased from the usual and well known suppliers:-

• NT30 Taper to MT2 converter. The two slots in the NT30 taper were not in line (by a good way) so the taper would not fit in the milling machine quill. Pretty basic requirement I would have thought.
• 1/2" x 32 ME Tap that proved so tight in use it stripped some teeth. On close examination there was no (as in zero) clearance relief angle. Again pretty basic. I have a box of theses taps – I hope they are not all the same. Needless to say, THAT supplier has lost my business for good.
• Wobbly drills purchased in a set. Same supplier as the tap.
• ER40 Collet Chuck to fit a Sieg C4 lathe spindle. After suffering unacceptable run-out of material held in the chuck I traced the reason to be a sloppy fit of the chuck register on the nose of the lathe spindle. Pretty fundamental for a collet chuck that the register is an accurate fit.

Mr supplier, i don't want cheap stuff. I want stuff that works!

[Chris TriceParticipant @christrice43267]

That's always been my battle cry but always get shot down by people saying you can send it back. I'm sure there is some good stuff out there but I like to buy 'with confidence'. I bought a boring head made in India that I later discovered was so far out of square I threw it away because the first time I came to use it was two years after I bought it and no dealer would entertain a complaint after that length of time, and an ER 25 collet chuck too tight to fit the lathe spindle went in the bin along with a set of unparallel expanding arbors expanded by a screw made out of cheese. Except for very simple items where the quality isn't critical, I nearly always buy good quality second hand western items and things like drills and cutters come from Dormer and their kin.

Edited By Chris Trice on 16/12/2014 11:08:23

[roy entwistleParticipant @royentwistle24699]

me dad used to say " buy cheap pay twice "

Roy

[MEinThailandParticipant @meinthailand]

Hi Chris,

Thanks for your support.

I live in Thailand so if I buy duff stuff from UK it has to go in the bin – no chance to send it back.

I love Japanese and Taiwanese tools, especially things like drills and taps from Japan. If it's Japanese or Taiwanese you can't go wrong.

I also bought a couple of Japanese carbide insert milling cutters from Ebay, 16 and 20 MM dia with the same Mitsubishi carbide insert. They cut steel like butter if you put on a good cut. Superb!

Recently I wanted an NT 30 taper tool holder to fit my Taiwanese Bridgeport clone – a superb machine – so I made my own. Now I make all my own insert tools for both bought carbide inserts and home-made silver steel or gauge plate inserts.

All newcomers to the hobby should have 'buy quality or struggle with cheap for ever more' drummed into them.

I know, my first lathe was a flat bed Drummond with the bearings so worn that you could lift up the spindle and take out the play with you hands. I had to take cuts so lightly that the spindle didn't lift. I have moved on since then (50 years ago) but it seems the industry hasn't.

[MuzzerParticipant @muzzer]

Hi MEiT

Mine's a Taiwanese BP clone too which also has the NMTB30 spindle. I've been able to find holders at reasonable cost and runout (doubtless some luck involved there!). Have you seen my quick change tool holder? Works a treat – one of the best tools I've made for it.

Murray

[Author]

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