New lathe arrived today : The ongoing saga

[AjohnwParticipant @ajohnw51620]

Posted by Ketan Swali on 16/11/2015 10:18:56:

Hi John,

I have just checked. Unfortunately, there isn't anything in ARCs current range which will fit Brians needs in respect of slitting saws and arbors for his lathe. All I would say to Brian is, what ever you choose, please be careful when using these products.

Ketan at ARC.

Doh – I assumed he had a 2 morse spindle. Not that chuck mounting matters that much, just that a morse fitting will cut more precisely.

I also meant to add that some people knock up a table to fit on the lathe so that it can be used as a sort of table saw.

John

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Edited By John W1 on 16/11/2015 11:01:09

[Brian JohnParticipant @brianjohn93961]

John : so with a morse taper abor, the chuck is removed altogether and mounted in the headstock spindle ? Both my headstock and tailstock are MT1.

[Ketan SwaliParticipant @ketanswali79440]

Posted by Brian John on 16/11/2015 10:54:35:

Ketan

1. Why ''be careful'' ? Are you referring to the danger of using spinning blades in the lathe or the possibility of buying the wrong thing ? Everything about the lathe is dangerous !

2. I have not tried the 8mm boring tool yet. I am more inclined to use either a 6mm indexable tip tool or an 8mm brazed carbide tip boring tool. I seem to get good results when turning with brazed carbide. I have been told that this is quite common with beginners as the HSS tools need to be kept very sharp to get good results. The brazed carbide is a bit more forgiving.

I am referring to danger of using spinning blades in the lathe, and how well they are secured before use, followed by regular checks to confirm that the nut has not come lose after each use.

Regarding boring, John W mentioned somewhere about the centre being somewhere around 7.8MM of something like that. I just wanted to know if the cutting point on the 8mm HSS boring tool was sitting at, below, or above centre of the material you wanted to bore.

Depending on various factors, the indexable carbide insert (based on radius at cutting point), or brazed carbide tool is more likely to chip in the hands of a beginner, so less forgiving than the HSS. This is not something I wish to debate. It is just an observation. Hence some of the suggestions on here to use the HSS could be a good starting point to learn and get the feel?, before progressing to carbide based products?.

Also, for the 8mm brazed carbide tipped tool, have you checked the minimum hole diameter you will need?.

For the 8mm HSS boring tool in your set, the minimum hole diameter suggests to be around 8.5mm, depending on how it sits in your tool post. May be it is still too high, but it would be good to know.

Ketan at ARC.

[JasonBModerator @jasonb]

I would think it has a larger minimum bore, say the cutting edge is at 7mm from the bottom of the tool then that is going to be a minimum of a 14mm hole depending on how much of the end is ground to give clearance below the cutting edge.

Ketans little set of 4mm bars work quite well in tight spaces

[Brian JohnParticipant @brianjohn93961]

It does not give the minimum hole diameter for the 8mm tool. There are two different types but I am not sure how they differ. It may be the hardness of the carbide tip.

**LINK**

That 6mm indexable boring bar may be a better bet. I think it might bore smaller holes.

When using a boring bar is it bored to within 0.1mm then finished with a reamer or is the reamer only used with drill bits ?

NOTE : the Arc Euro tool set is not with me now. It will be back in a few days.

 

Edited By Brian John on 16/11/2015 13:24:36

Edited By Brian John on 16/11/2015 13:24:57

Edited By Brian John on 16/11/2015 13:28:02

[JasonBModerator @jasonb]

The top one is for through boring, the lower for blind holes but could also be used for through holes.

You can ream after boring or just use the bored finish

The one in your existing set may actually not reach the full 27mm, may just do it if angled slightly but that will increase the minimum hole size

[AjohnwParticipant @ajohnw51620]

Posted by Brian John on 16/11/2015 11:04:04:

John : so with a morse taper abor, the chuck is removed altogether and mounted in the headstock spindle ? Both my headstock and tailstock are MT1.

Yes. There is usually a threaded hole in the end of the arbour so that it can be pulled back fairly firmly into the morse taper. Also handy for getting it out. There doesn't seem to be any MT1 ones about. There are MT1 arbours around that could be used to make one and I think Shereline also do one that is MT1.

The arbours are soft ended – morse taper end hardened and the part on the end left soft. They might be a bit much for your lathe and the dia of the ends may be too small for slitting saw support anyway.

You should be ok with a chuck held one. It's just that the morse taper types hold the saw more accurately.

John

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[Brian JohnParticipant @brianjohn93961]

Jason : I see, the lower one has a right angled tip. For the price, these seem like a good buy. I now have a bench grinder and a green wheel. I have found it very easy to give the brazed carbide tips a touch up to keep them sharp.

But I think the 6mm indexable boring bar would be able to cut a smaller hole. They do not give this information so I think it is a case of buy it and see !

UPDATE : minimum hole is 9mm for the 6mm indexable. Does that mean it will fit in a drilled 8.9mm hole ? I really need to know what size holes I have to drill to take the tool.

http://www.ebay.com.au/itm/RDG-TOOLS-INDEXABLE-LATHE-BORING-BAR-6MM-SHANK-TCMT-09-INSERTS-ENGINEERING-TOOLS-/351480492909?hash=item51d5deb36d:g:iOUAAOSwQJhUlC1c

 

Edited By Brian John on 16/11/2015 13:33:38

Edited By Brian John on 16/11/2015 13:40:35

Edited By Brian John on 16/11/2015 13:43:31

[AjohnwParticipant @ajohnw51620]

This is the typical min hole size for the smallest insert boring bar I can find. 3mm over shank size isn't that unusual. There may be smaller bars elsewhere on the site.

**LINK**

Remember though that when tips and bars are sold together it generally works out cheaper.

From Hopper's checks on your lathe drills and reamers are another option but do run the reamers as slow as you can and some sort of lubricants helps. Sets of reamers can be found fairly cheaply over a range of sizes. The super high precision ones tend to be rather expensive but often holes are made to accept things so the part that is to fit be it running, tight clearance or force fit it can be adjusted to suit.

Hand reamers have a taper on the end, Chucking and machine reamers don't.

John

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Edited By John W1 on 16/11/2015 13:51:39

[Brian JohnParticipant @brianjohn93961]

John : I am using hand reamers which I then mount in the tailstock drill chuck. This is probably not conventional but is it likely to cause problems or inaccuracy ?

[Neil WyattModerator @neilwyatt]

This is my smallest boring bar, the shank is 1/8" so good for ~>5mm+ holes.

I think it would work OK on your lathe Brian. I can't remember where it came from though. Perhaps Tracey or Chronos?

I also have an insert that needs a holder, a solid carbide boring bar for holes down to about 2.5mm, but only about 7mm depth, it even has a coolant hole in it!

[AjohnwParticipant @ajohnw51620]

Posted by Brian John on 16/11/2015 14:06:32:

John : I am using hand reamers which I then mount in the tailstock drill chuck. This is probably not conventional but is it likely to cause problems or inaccuracy ?

No. The only problem with hand reamers is that the tapered section on the end has to pass completely through the hole to get it parallel. Often that isn't a problem. I use either type in the lathe depending on what I have.

The usual instructions for using a reamer are, drill, bore and then ream. It assumes that the drilled hole might not be too good but with decent drills not just rammed in any old how and a reasonably set up lathe in respect to the headstock to tail stock alignment the difference is likely to be very marginal.

Really on you lathe one question that needs answering is how big a drill can you use on it. That might mean using several gradually opening up the hole. That and the tool post sets how big a boring bar you can use. The smallest size is set by what you might want to make. Sounds stupid but it wouldn't be difficult to make an HSS tool that would bore a 1/8 dia hole. Reamers may help you avoid having to make boring tools like that and larger ones. Sets might be a problem. For say 0.5mm steps from 3mm the only ones I have seen run up to 13mm. it may be better to buy as needed.

Parts can be made to fit in drilled holes as well. It's surprising how accurate they can be at times but a reamer gives a much better finish and that aspect is usually important.

1/8" holes and no reamer and didn't want to buy one? Many would make a d bit. The tolerance they give isn't all that much worse than a reamer. A reamer on well aligned gear should give a tolerance of it's actual size -0 +0.0005" usually relaxed a bit to 0.0007". A d bit should up that to around +0.0015". Good job too as accurate holes had to start some where to get where we are now. Once reamers get large the tolerances are usually increased.

John

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Edited By John W1 on 16/11/2015 15:50:42

[AjohnwParticipant @ajohnw51620]

This one has a 6mm shank and can bore an 8mm dia hole – Unusual for RDG to give info

**LINK**

There bars with the triangular tips going on the one I have wont face inside a hole as the tip isn't at the correct angle. The far edge is more or less square on.

John

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Edited By John W1 on 16/11/2015 16:18:41

[JasonBModerator @jasonb]

I have one of the Miniature CCMT ones that Glanze/Chronos do will go in a 7mm hole and will face the end of a blind hole, should be able to find them on e-bay.

EDIT, the ones at the bottom of the page

 

Edited By JasonB on 16/11/2015 17:30:02

[AjohnwParticipant @ajohnw51620]

I'll keep a link of that page Jason. The price of the tips for them isn't too bad either at £2 plus the usual each but they don't look like micro polished. Coated instead.

John

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[KWILParticipant @kwil]

John, you should note that the inserts offered are CCGT ie polished type for Al (and very good on S/S).

[JasonBModerator @jasonb]

Kwil it was the ones at the bottom of the page I was refering to which have a "Mini CCMT" tip which would equate to about an 04 size rather than the more common 06 and 09 and as far as I know they only come in MT though with an almost non existant tip radius so don't get pushed away too much. If I remember I'll bring one along on teh 28th if you are going.

 

EDIT

Pic of the "miniture CCMT" against a 6mm shank holder with CCGT 0602 tip

 

J

Edited By JasonB on 16/11/2015 17:28:19

[Brian JohnParticipant @brianjohn93961]

Today I purchased a 9.8mm drill bit and a 10H7 reamer for doing the smaller cylinder. I also bought the parallel shank arbor with three blades from Chronos so I know the blades will fit.

I think the 8mm brazed carbide boring bars will need a 10mm hole before I could even get them in there (my estimate). I think I will be better off with the 6mm indexable tip boring bar as that only needs an 8mm hole…or slightly less.

 

Edited By Brian John on 17/11/2015 08:00:38

[AjohnwParticipant @ajohnw51620]

You might find a drill set like this one useful on a lathe of your size Brian along with the boring bar at the top of the page that Jason linked to. The tips from the same source are well priced as well.

**LINK**

if nothing else the link lets you know that there are stub drills around. Much shorter than standard length. It's possible to turn the shanks down on drills if needed even using an HSS tool. Often people do that in the 3 jaw but for best accuracy on the hole they will produce it's better to use a 4 jaw and get them running true.

The ancient drill size for reaming is 1/64", circa 0.4mm less on the diameter but both less and a bit more can be used in practice. Maybe 1/2mm more if needed. Too close doesn't allow for slight drill run out that hopefully will be straightened by the reamer.

John

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Edited By John W1 on 17/11/2015 10:17:22

[Brian JohnParticipant @brianjohn93961]

So you think I should be buying a 9.6mm drill bit ? That seems a bit small to me. I almost bought the 9.9mm drill bit !

[VersabossParticipant @versaboss]

Posted by Brian John on 16/11/2015 13:32:50:

…

UPDATE : minimum hole is 9mm for the 6mm indexable. Does that mean it will fit in a drilled 8.9mm hole ? I really need to know what size holes I have to drill to take the tool.

…

As you usually use a boring tool to make a hole bigger, I don't see what you mean with this question. Do you want to open 8.9 mm up to 8.95? For anything bigger your question makes no sense.

Anyway, when you (or someone else) wants to bore really small holes, there are wonderful one-piece carbide tools around. Like these e.g.:

Regards, HansR.

Edit: this is just part of the catalogue, the diameters and lengths go up from this…
 

Edited By Versaboss on 17/11/2015 10:40:40

[Brian JohnParticipant @brianjohn93961]

Chronos have these two small ones on ebay. These are the same as on Jason's link.

**LINK**

**LINK**

I am not sure how readily available the inserts are but I will buy one of the mini boring tools to add to the slit saw and save on postage. I think the second one will be the easiest to buy inserts for.

 

Edited By Brian John on 17/11/2015 11:16:38

Edited By Brian John on 17/11/2015 11:18:43

[AjohnwParticipant @ajohnw51620]

The site Jason linked to is handled by Chronos Brian. You might not find the inserts for them on ebay – or you might. Payment can be made via paypal just like ebay.

£2 a piece is pretty good for insert but have to buy 10. but here we have to pay VAT. I believe that is usually included in ebay prices so you should get it refunded and wonder if you do.

Actually I just ordered a 16mm bar off the link that takes the same inserts. I had hoped to use the triangular ones I use for turning for boring as well but have the facing down holes problem with them. Insert price is something that should be considered carefully when buying holders – but the price difference wont cause me to switch to them for turning.

John

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Edited By John W1 on 17/11/2015 11:25:12

Edited By John W1 on 17/11/2015 11:29:43

[egaParticipant @ega]

John W1:

I'm pleased with the 16mm bar I recently bought from SPG – see opposite.

[Brian JohnParticipant @brianjohn93961]

John : thank you for that information. I bought the small mini tool from the Chronos/Glanze website ; it includes four inserts so that seemed the better buy.

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