Need to cut small grooves

[derekwarner_decoy]

OK PD's.....& Steve has explained a few things here....but a few questions for our more qualified members   
I remember 

1) for HSS we used al/oxide wheels & try to not let the stock get beyond STRAW colour prior to quenching

2) for tungsten carbide inserts we used a silicon carbide wheel + water cooling

30 years later ....walking around the machine shop I see many of these triangular cemented carbide inserts waiting for the rubish bin....could these not be re surfaced via a silicon carbide wheel + water cooling? or is this just a THROW away engineering society? ...

I have priced these tips for home use & @ AUD$9.00 per insert & divided by 6 = $1.50 per cutting face...which is still good $ value

A 10x10 mm x 80 mm long HSS shank in OZ is $7.00 ....see what I mean 

It seems that the HSS tool grinding processes we were taught 30 years ago....back rake, fore rake, chip rake etc .......are all near a thing of the past  Derek



 

[derekwarner_decoy]

OK PD's ...for the second time this evening

1) have reread to comments from Steve...looks like a periodontal error on my part. ...sorry.....any person responsible for 650 tonnes of steam condensate/hour is looking after a BIG number of units...is it all PLC controlled?

2) stick with PD's Steve... & after twenty postings or so  ........you may open your own FOLDER in Steam & comment on the Boyles & Charles Laws of Gas Equation's.....

[bogstandard]

Derek,

for tungsten carbide inserts we used a silicon carbide wheel + water cooling

I think we are getting slightly confused here. Green grit wheels are used for brazed carbide tipped tools, not for cemented carbide tip inserts.

Inserts are generally considered disposable once they have been chipped or dulled by use. Certain types can be resurfaced, and I do it myself, but really needs a diamond impregnated wheel or flat laps, with water as the lubricant.

I actually sharpen some new ones before use to allow me to do much finer turning work on difficult materials.

I think you will find, the old flat triangular six tipped ones are starting to go out of fashion. The types being used now come with toprake and front rake ready moulded in, but are usually single sided.

There is no comparison between tips and HSS tool bars. The HSS last many times longer than the tungsten tips. I have a favourite HSS tool that I have been grinding and touching up for a few years. In the UK I can get a length of HSS tooling for the same price as one cemented carbide tip.

http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/High-Speed-Steel-Toolbits

http://rdgtools.co.uk/acatalog/TIPS1_FOR_INDEXABLE_TOOLS.html

As I stated in the article on the other site, for most work done by model engineers, HSS toolbits will be a lot more effective than carbide.

John

[smuttley]

1) have reread to comments from Steve...looks like a periodontal error on my part. ...sorry.....any person responsible for 650 tonnes of steam condensate/hour is looking after a BIG number of units...is it all PLC controlled?

2) stick with PD's Steve... & after twenty postings or so  ........you may open your own FOLDER in Steam & comment on the Boyles & Charles Laws of Gas Equation's.....

No PLC's Derek, refineries of any size use something like this, main frame computer systems running controls and feed back to many central control rooms, for processing.

I think it will take a lot of skill to grind my own cutting tool, but as my machine is small, I must investigate this further. I would rather do things that suits my needs, and that is accuracy, very close tolerance and final product finish, no good building an engine and it looks like it's been turned and scratched with a pen knife,

[derekwarner_decoy]

Hi PD's....well I think that steamboatmodel & bogstandard have sorted us out .... ...just use HSS & be happy with it

Steve ...you must get the cleaners to look at those two floor tiles to the left...... ...............& keep a sharp eye on those LCD display's.............regards Derek

[smuttley]

Steve ...you must get the cleaners to look at those two floor tiles to the left...... ...............& keep a sharp eye on those LCD display's.............regards Derek

LOL

[antopia]

Hi Steve ,
I have been following this thread a little I have a very small lathe similar to the mini lathe, I can recommend that hss tools are much better,
your indexable tool will cut very well on brass,but their use on small machines are a bit more challenging on steel,for steel say 3/4 dia I would look
for about 3 to 4 thou of feed and 1000 to 1500 rpm with a 10 thou cut,this would be my starting point.These small machines cannot do much more on a cut as it will vibrate or deflect,I usually tell people hss cuts, carbide rubs it off,normally this is true as most indexable tips have no sharp cutting edge unlike a sharp knife.try it, an indexable tip will not cut your finger like a stanley knife will.

http://www.cromwell.co.uk/KEN0100120K
you can buy hss like this,I have used these and can recomend them,it is easy to regrind them as you can just follow the original angles
but the 3/4 dia steel bar you would want about 400 rpm and use a brush with coolant on.


Regards Steven

ps if you ever come across lots of used broken indexable tips don't throw them away 1 lbs of tips will fetch i think about £10.00 scrap value.     

[smuttley]

Hi Steve ,
I have been following this thread a little I have a very small lathe similar to the mini lathe, I can recommend that hss tools are much better,
you can buy hss like this,I have used these and can recomend them,it is easy to regrind them as you can just follow the original angles
but the 3/4 dia steel bar you would want about 400 rpm and use a brush with coolant on.

Ok, I am now getting what you guys have been trying to tell me, I did a lot of reading last night and I now understand a little more. Here is a link to my machine. https://www.machineryhouse.com.au/Products?stockCode=L148

It takes 12mm size tools and I was looking at getting a small set of pre ground, but I can only find Tungsten tipped types like this in Australia so far, https://www.machineryhouse.com.au/Products?stockCode=L008 Will they do the jobs?

I will have to do a lot more searching to find an Australian suppliers. Thanks for you help and guidance with this,

Regards

Steve

[bogstandard]

Steve,

Now you are talking about a different type of beastie from the cemented tipped tools.

The ones you are showing are the generally available 'brazed tip' variety, and are treated and used in a totally different way. Cheap and cheerful I would describe them.

The grade of solid carbide that is used is totally different to the moulded cemented type, and these can have a very sharp edge put on them.

I use a few of this type, mainly for single point screwcutting, and if treated with respect and set up correctly can do sterling service for a model engineer.

Remember the 'set up correctly bit'. They need to be set up perfectly on centre height, any deviation, and they will chip their edges quite rapidly. Unless you go for the big industrial jobbies, they should be treated like light, very sharp versions of HSS tooling, with a capability to cope with harder materials. No heavy cuts and keep them cool and well lubricated, otherwise the brazed joint is liable to melt and the tip will fall off. They can't stand up to the rigours of replaceable tipped tooling, which sometimes I use for very hard materials and I have sparks coming from the cutting face, try it with these and you are onto a loser.

It is this type, like Derek commented on, that can be resharpened on front and side faces with a green grit wheel. The top face should be dressed with a diamond lap with water as the lubricant as the final act. One swipe across the top face with a lap can bring all edges to a razor like sharpness.

If you are going down this route, you will require an offhand grinder with a fine green grit wheel and a small 'credit card' diamond lap (very cheap nowadays) to keep them sharp. If that is the case, buy a few HSS bits as well, and practise grinding your own, but not on the green grit side, that is a very soft wheel designed for grinding very hard materials such as tungsten, but on the 'grey' wheel side that normally they come mounted with. I don't want to start quoting grades and materials for wheels as it will only confuse the issue even further, grey and green is fine for the moment, and is the standard used on most model engineering tooling sites.

http://rdgtools.co.uk/acatalog/EVERYTHING_ELSE_ABRASIVE.html

http://rdgtools.co.uk/acatalog/DIAMOND_TOOLS.html

http://rdgtools.co.uk/acatalog/TOOL_STEEL___BLANK_S_.html

http://rdgtools.co.uk/acatalog/BRAZED_LATHE_TOOLS.html

http://rdgtools.co.uk/acatalog/worldwide_shipping.html

I use these people all the time, and a lot of my American colleagues have used them for special items that aren't available in the US, and they have all said that they have received good and fast service, and very reasonable postage rates. It might be worth sending them an email to get a few quotes for those unobtainable bits and pieces.

John

[antopia]

Hi Steve,

I have seen this type of tooling and I would agree with John they would need re-grinding too be of any use!.

here is a link that will help you
http://www.ameng.com.au/suppliers.htm


as always the choice of tooling is up to you,your machine is larger than mine so you may get carbide to work ok,on mini lathes it can be difficult.
but I would always advise on either hss or carbon steel tools in the beginning as they are less demanding on technique and more forgiving and will
produce good results.the hard part in todays world is not many people know how to grind them correctly and there are fewer people to "visit" and
be shown,make a good off hand grinding rest at least 3" x 4" ,there are plenty of designs on the web.I gave one away to someone who had been
modeling for many years,I ground a tool for him on his grinder and it surpassed anything he had tried but there was no grinding rest, he just did it free hand and had not got the angles correct.later on in the year I visited the individuals garden railway he showed me proudly the grinding rest and some tools he had ground.one of his words were "I wish I had,had that grinding rest 20 years ago",he is in his mid 80s ,it is a shame but this  does often happen, some people don't like model engineering clubs or cannot access them and don't have access to someone that knows.

most of my tools are old myford boat types which I have collected from either shows second hand or boot sales these are only carbon steel but
will produce very good results and some will be 30+ years old and more,I just re harden and temper when i reach the end of the "hard bit".
because I am a Yorkshire man it has to be cheap and cheerful (successful).

I do have some carbide tooling but these are for use on cast iron castings as I would ruin carbon tool steel if I used them.

Regards Steven

   

[smuttley]

Thanks Guys,

Very helpful info here, I will grab some HSS and have a go at grinding my own, practise, practise and more practise,

Thanks again

Regards

Steve
 

[MikeR C]

For a reasonable compromise between the ease of replacing inserts and the durability of high speed steel you might consider something like this:

http://littlemachineshop.com/products/product_view.php?ProductID=1724

The are not cheap, but neither are carbide inserts. I have access to a wide variety of carbide inserts from a machine shop and frequently they are tossed with one or two unused edges. I sharpen with a diamond hone and get quite a bit of use from them.

I have one of these diamond tool holders and while they don't do any one type of cut perfectly, as would a purpose ground bit, they do many things pretty well without having to change the toolholder angle. It comes with a sharpening jig that makes sharpening very quick.

http://www.bay-com.com/index.php?main_page=index&cPath=2&zenid=b9e7b0f76909ffead7b116a4f71772b2

I feel it was well worth what I paid.

Thanx
MikeR C