1st lathe questions….

[Chris RoseParticipant @chrisrose90563]

Hi All, i have just recently purchased a Chester cub 630 lathe, which came from a school, all is good with the machine. Ive converted the lathe to single phase with a tech inverter from drives direct….

I have a couple of queries regarding tooling… i purchased a cheap set of 12mm carbide tools from RDG, thinking they would be the right size to get me started.. looks like i was wrong…. I seem to have found that i have a tool post that will take a maximum of 24mm tool bars (measured), and it looks like from the bottom of the tool post slot to the point of the tailstock centre is just over 18mm…..so should i be using 16mm tooling???? with a shim to get the tool tip dead centre…..

Next question is does anyone know where i might be better to go too buy tools, as i'm now aware that buying the machine was the cheap bit !!

Could someone explain as to the difference regarding the types of tools with replacement tips i.e glanze TCMT etc….

Another question is ……should the tip of the cutting tool always be inline with centre of the work piece??

Where might i get hold of a set of change wheels for this lathe as they are missing…..

thanks all

[Chris RoseParticipant @chrisrose90563]

[john fletcher 1Participant @johnfletcher1]

Yes the lathe tool should be in line with centre of the work. Its easy to make a "stand " so that the lathe tool fits exactly underneath when at centre height. No harm done by asking RDG if you can exchange for the correct size, I've always found them helpful, after all there is no better advert than a satisfied customer and you might buy again.

Change wheels I'm not familiar with your lathe but when some comes up with the details of the gears, try HPC in Chesterfield or Davall of Hatfield. I have bought gears from HPC and they have a very useful catalogue. You could also try Chester, place an advert here or ebay. John

[JourneymanParticipant @journeyman]

Hi Chris, you could do worse than take out a subscription to MEW, Neil is currently doing a series on the beginners lathe. You are right! Getting the lathe was the cheap bit.

Good luck with the new machine

John

[not done it yetParticipant @notdoneityet]

12mm tooling might eventually be useful for some jobs. They just need that extra 4-6 mm thick ‘shim’ to get them to centre height. So no great deal if they cannot be refunded/exchanged. Learning on smaller cutters is cheaper than making mistakes with more expensive ones!

A good introduction to lathe cutting tools (just to confuse you further) might be the vid on this subject by ‘this old tony’ on u-toob. You might then understand that you need to start simple and progress at a rate that suits you. There are several explanations on the net for uses of the different inserts and tables explaining the codes for the letters.

What material you are going to be cutting might help sort out a few simple general purpose inserts, if you intend going this way.

Have fun making chips.

[John PParticipant @johnp77052]

 

 

Hi Chris,

The Chester cub range is the same as the GH range of lathes
sold by Warco about 20 years ago ,i think they stopped selling
them about 2004.
Warco may be able to get a set of change wheels for this machine.
The wheels listed in the manual are 12 gears 27 to 30 tooth
33 to 36 tooth 38,41,43 and 45. They are 2.5 module.

I wrote an article in MEW 257 page 9 showing how to
make simple splined hubs for some 127 tooth conversion
gears.
The text mentions Fig1 showing these but it was missing
in the published article.
The two photo's here are from the article.

John

Edited By John Pace on 08/02/2018 20:06:23

[BazyleParticipant @bazyle]

12mm tools are perfectly adequate as you are not meant to use the absolute biggest you can cram into the holder. You should always leave room to shim up to height . Most of the time 1/4" or 3/8" HSS are the best to use and available on ebay as a bunch of used ie ready ground to some weird shape for a quid each.

[HopperParticipant @hopper]

+1 on keep your 12mm tooling and add shims below to bring the point to centre height. 16mm tooling gets in the way on small jobs sometimes. Just get some 4mm flat bar and or a couple of bits of 2mm stacked to use for shims.

Yes, tool point is generally on centre, or sometimes slightly below. Not above or it will rub.

[Howard LewisParticipant @howardlewis46836]

+1 for making a Tool Centre Height Gauge. It will save you hours of frustration and wasted time, and probably material.

ANY chance that Chester (or Warco) could supply the missing changewheels?

Failing that, if you can't get them via the "Wanted" section on here, maybe you could find some kind soul who would make them for you, (you would learn as the work was done together). If you could, at least, get dimensions, DP / Mod no, it would be a start.

Whereabouts are you?

Can you find a Model Engineering Club nearby, where you may be able to get help?

Howard

[John PParticipant @johnp77052]

I see from an earlier posting a suggestion was made about
buying a set from HPC gears ,looking at their listing
of gears to replace all 12 indicated in my later posting
at 2.5 module would be £722.29 inc the vat.

The bought gears at 30 mm wide would need to be reduced to
10mm wide to fit on the machine additional work would be
required to modify the hubs to suit the machine fixings.

RDG tools don't list 2.5 module cutters but do have 10 dp
which would do providing a full set of gears were to be
made would be satisfactory ,only cutters 3 and 4 would
be required to do the gears needed and at about £23 each
would seem to be an economic way to go.

The original gears are cast iron and 20 deg pressure
angle ,the RDG cutters are 14.5 deg pressure angle
As the gears would most likely be made in steel the
slightly thinner tooth profile would be still strong
enough.

[Keith LongParticipant @keithlong89920]

John, before you buy gear cutters have a look at the following webpage – link – the cutters there are 20deg pressure angle so would run happily with your existing gears. I've found that meshing 14.5 deg pa with 20 deg pa the running characteristic feels very "notchy" as the gears do stick and then clear due to interference between the teeth. It could give you chatter problems.

It could also be worth contacting Chester Machine Tools if you haven't already as in the past they have had a box of miscellaneous gears, at their sales open days and at the occasional shows that they've done, for you have a rummage through. I don't know what those gears have come from but change wheels for your lathe might just be amongst them

I've not used gear cutters from CTC but other tooling (ER collets) have been excellent for my needs – just a happy customer.

[John RuddParticipant @johnrudd16576]

One more thing to consider for tooling size choice….if you start using 16mm hss blanks and grind your own, it takes a lot longer than making from smaller blanks like 12mm,which is big enough imho….plus 12mm stock is probably more readily available from the likes of Arc/RDG etc…..

+1 for contacting Chester re gears, I rummaged through their box when I was at Harrogate last. Managed to get a couple or three gears for my 9 x 20 to make a tumbler reverse…..cost about £10 iirc..Ask for Tony, very helpful he is…

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