Author Topic: Insert Boring Bars - any hints or tips please?  (Read 5907 times)

Offline propforward

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Insert Boring Bars - any hints or tips please?
« on: August 31, 2018, 01:22:05 AM »
Can anyone give me some advice on what to look for in boring bars that use inserts?

I have not had much luck with my cheap set of brazed carbide boring bars. I haven't given up with that, but I want to be able to machine smaller bores than my set will allow, so I was looking around for small boring bars sets and found this:

https://www.travers.com/everede-set-1-steel-boring-bar-set-3-different-316oslash-34oslash-with-cdcd-07-cvm2-coated-inserts-right-hand/p/24-570-786/

It looks like a good, general purpose set, that will cover a good range of model engineering bores.

Comments, thoughts? I have zero experience of insert tools. I grind my own HSS tools for external machining - works plenty well enough, but I need something a bit better for boring.
Stuart

Forging ahead regardless.

Offline b.lindsey

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Re: Insert Boring Bars - any hints or tips please?
« Reply #1 on: August 31, 2018, 02:02:48 AM »
Well the description say 3 boring bars, the picture shows four but also only lists two diameters. Curious as to what is actually included :thinking:

Bill

Edit: what minimum and maximum bore sizes do you contemplate making over time?

Offline zeeprogrammer

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Re: Insert Boring Bars - any hints or tips please?
« Reply #2 on: August 31, 2018, 02:36:13 AM »
A bit pricey for me but I'm interested in seeing what you find out.

I'd bought an accusize off amazon and it's done what I want but I'm still learning.
Keep in mind...I have near 0 experience with such things.
I've had more 'luck' with cheapo carbide I got from LMS.

If you're thinking to try index versus carbide...maybe go for something cheaper or smaller and try it out?

I do like index for turning/facing but others may argue that other cutters are better.

I'm no help. I know.
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Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #3 on: August 31, 2018, 02:50:32 AM »
I'll take any opinions right now. I don't mind spending a bit on the "right" tool if it's good quality and will last, but the range of available tools is overwhelming and I don't know where to start.

I'm going to look into that accusize, just to see what it is.

Edit - that accusize looks like what I am after for larger bores.  :ThumbsUp:
« Last Edit: August 31, 2018, 02:55:29 AM by propforward »
Stuart

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Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #4 on: August 31, 2018, 02:53:19 AM »
Well the description say 3 boring bars, the picture shows four but also only lists two diameters. Curious as to what is actually included :thinking:

Bill

Edit: what minimum and maximum bore sizes do you contemplate making over time?

Travers descriptions are poor, they seem to use the same heading for multiple items. The set I showed has 4 different boring holders in it. At least when I read the product spec that's what it looks like to me.

I would like to bore 1/4" upwards - or do people generally just drill and ream that size, and start boring on larger diameters?
« Last Edit: August 31, 2018, 02:56:21 AM by propforward »
Stuart

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Offline Ian S C

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Re: Insert Boring Bars - any hints or tips please?
« Reply #5 on: August 31, 2018, 03:02:53 AM »
For the smaller sizes, stick with HSS, apiece of 1/4" HSS will grind up to make a boring bar from(in my case) 3/16" up, and seems to last for ever.  I do use carbide tools, but only for larger stuff, or as in the last big job, boring out 30 mm holes that had been gas cut to 35 mm.

Ian S C

Offline zeeprogrammer

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Re: Insert Boring Bars - any hints or tips please?
« Reply #6 on: August 31, 2018, 03:09:13 AM »
1/4" bore is pretty small. Drill then ream?
My problem with boring has been getting a large enough hole that the boring bar will fit into.
Generally on the order 7/16".
But I know some members make their own boring bars (and I don't) so their range is much different.

Please keep in mind...I really don't have the experience of others.
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Online crueby

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Re: Insert Boring Bars - any hints or tips please?
« Reply #7 on: August 31, 2018, 03:14:38 AM »
I like the small boring bars, mine goes to about 5/16". Great for doing sizes that I dont have reamers for, as well as square bottom holes. They also dont wander on long holes like drills can.

Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #8 on: August 31, 2018, 03:16:55 AM »
Maybe I'm trying to go too small? Maybe I should start with a 1/2" bore and figure that out first?

EDIT: crueby posted while I was typing, and sums up exactly my interest in boring holes to size.
Stuart

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Offline zeeprogrammer

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Re: Insert Boring Bars - any hints or tips please?
« Reply #9 on: August 31, 2018, 03:45:14 AM »
One of the things that I ran into...wasn't just the boring hole size but the depth. Keep that in mind too.
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Offline Steamer5

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Re: Insert Boring Bars - any hints or tips please?
« Reply #10 on: August 31, 2018, 09:54:25 AM »
Hi Stuart,
 I’m no expert, I got mine from Greenwood tools in the U.K. ( not the cheapest )there bars start with one that will do 6 mm.
Range runs 6,8,10,12 mm. There site will tell you the max depth etc.
recently used my 12mm to bore a tube, 100mm, to a nice sliding fit on a 19mm rod, lots of passes with no adjustment to take out the spring.
The QCTH I made for the 20mm bar of had for 15 years is going to help lots for any bigger holes in the future! Thinking of getting some more bars to fill in the gap!

Cheers Kerrin
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Offline kvom

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Re: Insert Boring Bars - any hints or tips please?
« Reply #11 on: August 31, 2018, 12:35:58 PM »
The travers set is 4 bars with 3 different size inserts.  For small bars I use solid micro carbide bars.  Can fit a 1/4" hole but obviously limited in depth.  My goto bar for long bores uses inserts and is 3/4" diameter.

Offline Ian S C

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Re: Insert Boring Bars - any hints or tips please?
« Reply #12 on: August 31, 2018, 01:52:49 PM »
This reminds me that there is a boring bar with a carbide insert with the Box - Ford A at the Menzshed, must get it out and see what size, got about a dozen spare tips for it.
Ian S C

Offline Baner

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Re: Insert Boring Bars - any hints or tips please?
« Reply #13 on: August 31, 2018, 02:17:53 PM »
Using insert tooling in hobby situations is one of those 'can of worms' topics. The usual argument runs something like: Insert tooling is developed for high speed, high rigidity, high accuracy CNC and doesn't suit the slower, less rigid, less accurate typical hobby lathes. However, plenty of home workshop's use them successfully . You can google HSS vs Inserts and find out all about it... :o

The main flaw for the home shop user, I feel, is the cost.

For Boring Bars, a simple clamp type HSS boring bar is incredibly versatile - one bar can be used for boring, internal threading, internal grooving etc. by simply grinding the tool bit to different shapes. In the case of indexable tooling a different bar plus a different insert is needed for each of the above operations.

I think it also comes down to how you work. When I use my indexable tooling the lathe is normally screaming at top speed, showering hot blue chips everywhere. I prefer the slower, gentler HSS cuts.
But there is a time and a place for both, and plenty of pros and cons to each.

My own boring bar collection is weighted to the side of indexable tooling (for no good reason), though making a better selection of HSS clamp types is high on the 'round tuit' list.

Anyway I'd suggest buying just the one indexable bar and a couple of different inserts and try them out before dropping a ton of money on a set.

But which one to get?

There are all kinds codes that refer to different holders and inserts, but for hobby use one of the more common (and the ones I use) are designated SCLCR for the holder and CCMT 6020x (Metric) or  21.5x (US)for inserts. The codes all refer to tool geometry.

SCLCR boring bar holders for CCMT 6020x (21.5x) are available from 6mm-20mm. You can also get regular turning tool holders from 8mm-16mm. This means you only need to buy one insert style for a wide range of holders. I don't think any other common inserts fit such a range.

There are various options for CCMT. For instance, the last number in the code (x) designates corner radius at the cutting tip: 60202 (21.50) is 0.2mm, 60204 (21.52) is 0.4mm etc.  This is important for hobby lathes as the larger radius makes for more cutting pressure, so more deflection and chance of chatter etc. You can also get  CCGT 6020x which is an insert for aluminum, CCMW 60204 which is an insert made of HSS, and CCMT CBN inserts which are ceramic, made for turning hardened steel.
CCMT's are readily available and there are plenty of cheap options.

This is just basic info for one style of holder and insert. Some other common hobby holders/inserts are: SDJCR/DCMT and STFCR/TCMT though they haven't the same range of bar sizes.

And there are hundreds of others. :)

HSS boring bars are easy by comparison. They are readily made at home, or purchased fairly cheaply. There's a book by GH Thomas called Workshop Techniques that has an excellent chapter on boring in the lathe, with how tos for making small hole boring tools and HSS boring bars. (The rest of the book is good too.)
Also this video covers making HSS bars:
<a href="https://www.youtube.com/watch?v=O9d_I0A4kzg" target="_blank">http://www.youtube.com/watch?v=O9d_I0A4kzg</a>


That's maybe more information than you wanted, Stuart.  ;D
All the fun of choosing tooling...

Dave.


Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #14 on: August 31, 2018, 02:35:17 PM »


That's maybe more information than you wanted, Stuart.  ;D
All the fun of choosing tooling...

Dave.

On the contrary, this is precisely the information I was looking for. I use HSS tooling for the same reason as you - I like to work slowly in my machining. So I was looking to find a boring bar set that maybe used HSS inserts - someone posted such a tool recently, but they couldn't remember details about the tool, or brand, and it seems to me that HSS inserts are pretty much unwanted in the manufacturing world, so likely approaching unobtanium.

Thank you for your thorough and detailed post. Based on that, I'm going to try the home made HSS route first, and look up that book. If I do try an insert tool, I'll likely do as you suggest and try a single bar with the more common inserts for a larger size bore. In the meantime I'll work on some HSS.

 :ThumbsUp:
Stuart

Forging ahead regardless.

Offline b.lindsey

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Re: Insert Boring Bars - any hints or tips please?
« Reply #15 on: August 31, 2018, 02:50:57 PM »
Check the A. R. Warner Co. They have single boring bars in various sizes that use their HSS or Carbide inserts. They have good quality tools and in sizes suitable for smaller machines as well.

Bill

Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #16 on: August 31, 2018, 02:53:03 PM »
Purely by chance I happened upon this site just now, with this tool with HSS inserts.

https://www.arwarnerco.com/Kit-13-3-8-inch-Boring-Bar-C-p/kit-13.htm

So I'll keep that in mind, but I'm still going to look into grinding my own tools first - I did have success with that on external turning tools, so with some direction maybe I can get where I want that route.

EDIT: Timing! Thanks Bill - appreciate the heads up.

Stuart

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Offline b.lindsey

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Re: Insert Boring Bars - any hints or tips please?
« Reply #17 on: August 31, 2018, 03:00:49 PM »
Mine is the same size but uses the triangular inserts.

Bill

Offline Chipswitheverything

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Re: Insert Boring Bars - any hints or tips please?
« Reply #18 on: August 31, 2018, 03:05:46 PM »
Hi Stuart, very much second Dave's recommendation of looking up what Geo. H. Thomas has to say about kit for boring smaller holes, he covers the subject in a very effective way with gear that can be made cheaply in the home workshop. He gives a lot of detail on tool forming and the holders. 
 You don't necessarily have to grind the boring tools from HSS, silver steel ( drill rod ) will turn and shape quite easily and is fine for many jobs when properly hardened and tempered.  I mostly use this type of tooling, down to little boring tools about 1/8" wide, good for forming a really true hole to start a reamer, for instance on something that warrants that attention.    The two larger bars with the brown ends are from a design by "Martin Cleeve" in a 1960's Model Engineer, a BMS shank with a H & T silver steel end, the HSS tip secured by a screw inside the tapered end.   ( Apologies for rather rubbish photos! )     Dave


« Last Edit: August 31, 2018, 03:08:54 PM by Chipswitheverything »

Offline Steam Haulage

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Re: Insert Boring Bars - any hints or tips please?
« Reply #19 on: August 31, 2018, 03:19:15 PM »
 :old:
I know that a debate rages often occurs between advocates of HSS and carbide inserts. With that in mind when I had the opportunity to have a newly equipped workshop I made what has turned out to be an irrevocable decision asnd settled on Carbide.
As has been said the main problem for the hobby user is cost, any mistake can work out expensive. However I looked back at various machine shops I had acquaintance with in the UK. (I have never worked as a machinist but in most cases I had access to the shop records to see their buying patterns.). One thing became pretty apparent, with few exceptions the Manager/ Superintendant had elected to use only one make of inserts, and again mostly the same makers tool holders. After a few enquiries I found they had built good relationships with the suppliers and had access to a deeply knowledgable body of information.
I don't believe we have any chance to build these sort of relationships but I have done my best to garner such information as I need from the two or three suppliers I use.  So far I have been able to bore cylinders fulfilling the main criteria for such work, e.g. parellism, roundness, fine finish, adopting methods suggested by them.
I settled on Kennametal and have no regrets.
So far I have spent out a sum well within the limits set by SWMBO, and as far as inserts are concerned where I have bought packs of 5 I still have 3 or 4 of each type. Possibly enough to se me out.
Jerry
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Offline Baner

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Re: Insert Boring Bars - any hints or tips please?
« Reply #20 on: August 31, 2018, 04:14:08 PM »
Glad you found the info useful Stuart.

I managed to muddle GH Thomas's books. The one with Boring tools is called 'Model Engineers Workshop Manual'. Had a look around and it seems to cost a fair bit more these days than what I paid for it. :(
If you like I can probably scan the chapter on boring tools and send it to you.

Dave.

Offline jonesie

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Re: Insert Boring Bars - any hints or tips please?
« Reply #21 on: August 31, 2018, 05:29:08 PM »
i have that same set and they work great.i use them all the time.would highly recommmend.

Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #22 on: August 31, 2018, 06:16:45 PM »
Glad you found the info useful Stuart.

I managed to muddle GH Thomas's books. The one with Boring tools is called 'Model Engineers Workshop Manual'. Had a look around and it seems to cost a fair bit more these days than what I paid for it. :(
If you like I can probably scan the chapter on boring tools and send it to you.

Dave.

Thank you - I appreciate that and will take you up on the offer if you can do it. I ordered the other book you mentioned from the UK, but Model Engineers Workshop Manual seems very much more rare. I'll PM you an email address. If the file is large I can send you an upload link to use also.
Stuart

Forging ahead regardless.

Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #23 on: August 31, 2018, 06:19:43 PM »
i have that same set and they work great.i use them all the time.would highly recommmend.


This is very good to know - thank you.


Thanks everyone for your inputs - very helpful all of them. I've decided to "tread lightly" initially, and start with ground HSS rod (just ordered some). I may then order one of the nice HSS insert holder bars, but the ground blanks is an inexpensive starting route, which once I have had some success will give me confidence to go a bit more advanced. Most likely now is the time to make that tool grinding jig I've been promising to make for myself, which at the same time will be more practice before going to far on my engine castings.
Stuart

Forging ahead regardless.

Offline cwelkie

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Re: Insert Boring Bars - any hints or tips please?
« Reply #24 on: September 01, 2018, 01:51:51 AM »
A little late to the party but for what it's worth I very much second using the GHT holder for small boring bars and other cutting tools that only come to mind after you have the versatility it offers.  This holder is an extremely good solution for holding carbide boring bars such as those made by Micro 100; all it takes is an adapter sleeve to suit the bar's diameter.  They are pricey but they have become my go-to boring bars for small holes ... they are stiff beyond belief for a given diameter.

Besides - it's a nice little project!
Charlie

Offline zeeprogrammer

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Re: Insert Boring Bars - any hints or tips please?
« Reply #25 on: September 01, 2018, 02:34:57 AM »
I got the Accusize S06M-SCLCR2 / M2.5x6/T8 17211 from amazon.
Looks similar to the one you posted but about 1/3 the price.
I haven't used it much so I can't give a review.
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Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #26 on: September 01, 2018, 02:53:23 AM »
Oh yes - absolutely. Definitely looking into that. I think that might be a good add. Going to try grinding a few HSS tools first, and go from there, but that accusize tool is a nice price for what you get.
Stuart

Forging ahead regardless.

Offline john mills

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Re: Insert Boring Bars - any hints or tips please?
« Reply #27 on: September 01, 2018, 01:30:54 PM »
it is good to see you are going to grind your own boring bars from high speed steel ,in small sizes they can be very sharp and cut very easily .can be used for small holes 1/4 " is not the smallest holes any hole for precise position should be bored even if finished by reaming.I use lots of turning and boring bars made with brazed on tips made from plain grades of carbide .they must be ground with the right type of grinding wheels.they can be shaped with small radii and can be very sharp and will produce good finish.mild steel shank can work as good as any thing at a fraction of the cost.when you see the shape on high speed steel that work you could try the brazed on tools.Most of the commercial  tools i have seen are only semi finished and need to refinish ground be for they can be used.The problem these days lots of tip are coated grades and don't suit silver soldering.I spent lot of time on milling machines  when i used lots of plain grade inserts seco s25m was a favourite of mine.with CNC machines then indexable inserts are essential  but at home and in manual machines often brazed on tips are very usefull . 

Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #28 on: September 01, 2018, 01:34:21 PM »
Yes indeed - and armed with some info that Baner kindly sent me, I have some new tooling to make. The excerpt he sent me is really thorough and helpful. It has an introductory passage that rings very true:

“I suppose that many workers start off with their first lathe and a “set of tools” which, in my case, were forged carbon steel and included a “boring tool” which looked like a miniature golf club, and was just about as useful for its purpose. Every attempt to use it involved grinding something off it somewhere so that, in the end, it resembled nothing so much as Harry Lauders walking stick! To give a beginner one of those tools and expect him (or her) to bore successfully any hole that comes along is enough to put him off for life. I can quite understand why so many workers adopt the  drill and “poke a reamer through” technique”.

Stuart

Forging ahead regardless.

Offline john mills

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Re: Insert Boring Bars - any hints or tips please?
« Reply #29 on: September 01, 2018, 01:51:23 PM »
50 years ago as an apprentice we started grinding tools instructors would grind drills so we could practice.
working as an engine re conditioner most of the machines were special and had there own sharpening jigs and lapping divices.line boring tools still hade to be ground brazed on carbide ,the pin borer was solid carbide .in those days indexable tips and tools were limited on what was available an the work i did then didn't have much to do
with them .I gess thats why as apprentices at school they spent a lot of time with what shapes were required . 

Offline Niels Abildgaard

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Re: Insert Boring Bars - any hints or tips please?
« Reply #30 on: September 01, 2018, 03:13:03 PM »
In middle Europe the on plus ultra is made by Ifanger

https://www.ifanger.com/system-ifanger-86.html

How many times diameter depth holes are in Your mind?

Offline propforward

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Re: Insert Boring Bars - any hints or tips please?
« Reply #31 on: September 01, 2018, 08:05:58 PM »
Hi Niels, thanks for the link - very intriguing.

I haven't really thought about depth vs diameter - obviously the greater the number of depth X diameter, the harder it will be to bore. Essentially, I just want to progress to boring holes with a lathe. I've avoided it for a long time, but it's a very important thing to be able to do confidently. My main interest of course is boring cylinders for model engines, but having got some confidence with it, I expect it will open up many more possibilities.
Stuart

Forging ahead regardless.

Offline Niels Abildgaard

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Re: Insert Boring Bars - any hints or tips please?
« Reply #32 on: September 02, 2018, 09:18:41 AM »
I found an old picture of my collection of Ifanger(Swiss) and Komet(DDR) boring bars and heads.
In my expirience rigidity is the important thing.
I made my own boring bar holders,use the biggest possible boring bar with the shortest possible overhang.
I like carbide but the HSS Ifanger and Komet things are so easy to sharpen that I prefer them most of the time.

https://www.homemodelenginemachinist.com/attachments/im000178-jpg.45155/

Offline Stuart

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Re: Insert Boring Bars - any hints or tips please?
« Reply #33 on: September 02, 2018, 10:57:26 AM »
Sorry I cannot see the pic you need to be logged in to see it
My aim is for a accurate part with a good finish

Offline Niels Abildgaard

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Re: Insert Boring Bars - any hints or tips please?
« Reply #34 on: September 02, 2018, 11:53:05 AM »
Found some old pictures

https://imgur.com/E84bmkC

https://imgur.com/nleyOMO

https://imgur.com/CW9kfX8

My next generation boring bar holders had two paralel holes and were made from  60mm square mild steel
« Last Edit: September 02, 2018, 12:00:55 PM by Niels Abildgaard »

Offline Stuart

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Re: Insert Boring Bars - any hints or tips please?
« Reply #35 on: September 02, 2018, 12:35:54 PM »
Thank you for taking the trouble to make them viewable
My aim is for a accurate part with a good finish

Offline gary.a.ayres

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Re: Insert Boring Bars - any hints or tips please?
« Reply #36 on: July 14, 2021, 10:31:40 PM »
Hi Stuart -

Agree that finding the right tool for small bores is tricky, and these look good - albeit a bit pricey.

 

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