What is the difference between these two boring bars ?

[Brian JohnParticipant @brianjohn93961]

This looks like a good buy but what is the difference between these boring bars ? Any idea what the minimum size hole would be for these ?

**LINK**

[Brian JohnParticipant @brianjohn93961]

Different types of boring bars ?

[mechman48Participant @mechman48]

Ok for roughing out cast iron/steel/brass bores, looks like one is for through bores & other for boring to a internal shoulder, flat bottom… most of our ilk tend to progress onto HSS or indexible tip, trouble with these is you need a silicon carbide grinding wheel to touch up the tips & these leave a lot of dust around ( very soft ) to get into all your machinery nooks & crannies. No doubt others have differing opinions, & many have made bars out of broken mills or taps to suit what they are doing… I have.

George.

[frank brownParticipant @frankbrown22225]

Top one 12mm, bottom 14mm ? Just scaling up by using the bar diamension of 8mm. If they are too tight just grind away the back of the tool. If you go deeply into a tight hole, the top and bottom corners of the square might need taking off.

Frankk

[Ady1Participant @ady1]

I have the box set of 8mm tooling containing them both, the minimum hole is about 11mm

They are prone to flexing and chipping, the carbide is slightly softer than my old blue set (more sparks on the green grit wheel)

Very useful though, in the hands of a skilled person

Edited By Ady1 on 07/06/2016 10:42:04

[Brian JohnParticipant @brianjohn93961]

I have one of these Glanze 8mm boring bars already.

**LINK**

I thought those other two might be less prone to flexing but apparently not.

Note : I already have a bench grinder fitted with a green wheel so that is not a problem.

[Raymond AndersonParticipant @raymondanderson34407]

Remember when boring with the biggest Ø bar you can fit in the hole, you MUST have clearance for swarf [unless it's a through bore ]. The Glanze is the better of the bars in your pics.

[Brian JohnParticipant @brianjohn93961]

Do these two boring bars use the same inserts ? I think they do.

The 790550 by Glanze which I have already :

**LINK**

and the ebay set . the boring bar here is 150mm which is 50mm longer than the Glanze.

**LINK**

[Ady1Participant @ady1]

If you want to bore small holes and reduce flex issues then learning about D-bits may be the way to go

[Jon GibbsParticipant @jongibbs59756]

I'm with George. I've never had any luck with the cheap TCT tipped boring bars for anything other than roughing at high-ish speeds.

I use preformed HSS tools like this…

for small holes with power feed and plenty of spring cuts cutting in one direction only.

For larger ones I use homemade MS boring bars with short HSS inserts of various geometries held in with set screws.

HTH

Jon

[Brian JohnParticipant @brianjohn93961]

Jon, I have a tool like that but I am not sure how to use it. I tried to set it up in the tool post but I had no luck with it (It would have been much too short anyway). Can you post a photo of your tool post setup with that tool. Is the tool tip set at centre height as per other cutting tools ?

[Steve PaveyParticipant @stevepavey65865]

I find it best to set the tool tip at a gnats above centre height on a boring bar. If there is any deflection it tends to decrease the depth of cut – if you set it below then the depth of cut increases as the load increases, causing more deflection, which increases the load, etc etc.

[Jon GibbsParticipant @jongibbs59756]

Hi Brian,

To avoid rubbing, the tools will satisfactorily only bore holes with diameter at least twice the tool-size, without modification. So, a 6mm tool will only bore 12mm or larger holes and so on. This is because the business-end looks very much like 1/4 circle. You can relieve them slightly but basically that's the limit.

I set mine to cut on-centre but can see that a gnats above also makes sense. I grind mine pretty much as they came so that they cut like a left hand knife tool as they are plunged into a hole – taking account of the necessary clearances inside the bore.

I'll take a photo when I get chance.

My other boring tools follow the sort of design described here using 7/16" or 1/2" MS…

**LINK**

The one described here is for refining a bore with shear-cutting.

Jon

[Jon GibbsParticipant @jongibbs59756]

Hi Brian,

Here is the small boring tool – in this case a 10mm one. I slightly angle the tool to create a bit more clearance behind the cutting edge but set it on-centre…

…and here's a homemade boring bar using a length of 7/16" square EN3B and a piece of 1/4" round HSS…

The cutting tool is held by a setscrew and rod down the inside length of the boring bar with a 5mm ball bearing onto the toolbit.

HTH

Jon

Edited By Jon Gibbs on 08/06/2016 16:19:39

[Steve PaveyParticipant @stevepavey65865]

 

These boring bars are nice, and not too different to the ones Jon shows above:

(Why is it so difficult to embed a link on an iPad? Something that takes me 2 seconds on a laptop and impossible on a tablet that thinks it knows best when it comes to selecting text, grrrr.)

 

Edited By JasonB on 09/06/2016 08:29:35

[Raymond AndersonParticipant @raymondanderson34407]

Brian, The 2 Glanze boring bars you linked to use different inserts from each other, the top one uses CC** and the bottom one uses WC** I will stick a few pics up of various types later on today so you can see the different inserts. SCLC are the most versatile type as they will do through holes and blind holes, other types are more specific.

[JasonBModerator @jasonb]

Raymon/Brian the first tool that you already have uses a small CCMT type tip.

From measuring mine would be something like CC?T 050202 thats 5mm face length, 2.4mm thick and 0.2mm tip.

Both those bars will face the bottom of a blind hole.

So brian you will need to keep another range of tips if you get the bigger indexable bar unless you have other tools that take the CC** 06**** inserts

 

Edited By JasonB on 09/06/2016 10:39:49

[Raymond AndersonParticipant @raymondanderson34407]

Jason / Brian, Slightly confused here, [probably down to me ] If Brian means both the types of bars on the same page as his link, the SCLC R and the SWUC R, then they are different inserts CC** 06's for the SCLC and WC's for the SWUC. unless of course, he means the one he already has compared to the e bay set. in his other link.

Cheers.

[JasonBModerator @jasonb]

Raymons, in the first link Brian is refering to the 790550 that is towards the bottom of the page, he already has one of these. Not the second one on the page which as you say has the W type bloated triangular inserts.

[Raymond AndersonParticipant @raymondanderson34407]

Thanks Jason I see the bar he has now. EPMW inserts are fairly rare. Having a look through the paper catalogues I have, the smallest size is 04 and the only makers I can see are Stellram and Sumitomo. although there will no doubt be others.

cheers

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