Different ways of boring a hole

[Ian Skeldon 2Participant @ianskeldon2]

So Jason, if I understand correctly, the work piece is fastened onto the saddle with a special clamp arrangement, and travels along the bed with your home made tool mounted in the chuck and supported by the tail stock centre. Bore size increased by adjusting the tool. That's very clever, I would never have thought of doing that myself, thanks for sharing.

[Paul LousickParticipant @paullousick59116]

An interesting definition of DRILL and BORE (a hole)

In machining we refer to boring as an operation to enlarge an existing hole on a lathe with a boring bar or on a mill with a boring head, and drilling as using a bit (twist drill, etc) to cut a new hole. But in early days we used a brace and bit to bore a hole. Not to enlarge a hole but to make it in the first place.

We bore a hole in the ground to to get underground water with a drill. A single operation where the hole is not enlarged with another cutter. (Then a pipe inserted in the hole to extract the water.) On an oil rig, a hole is drilled in a similar operation to get oil.

What is your experience with the definition,

Paul.

[Phil PParticipant @philp]

If you go to about half way through this video, it shows a typical setup being used.

**LINK**

Some of his other video's are worth a look too.

Phil

[Enough!Participant @enough]

Posted by JasonB on 14/07/2019 19:22:02:

The photo shows the boring bar that I made from 35mm dia steel to take a "Microbore" head ….

Thanks, Jason. Very interesting. Might be worth a one-pager in MEW …. there ought to be more of those.

[Neil WyattModerator @neilwyatt]

Posted by Paul Lousick on 14/07/2019 23:35:34:

In machining we refer to boring as an operation to enlarge an existing hole on a lathe with a boring bar or on a mill with a boring head, and drilling as using a bit (twist drill, etc) to cut a new hole. But in early days we used a brace and bit to bore a hole. Not to enlarge a hole but to make it in the first place.

Strictly speaking I would say we make holes with drill bits that fit in a drilling machine.

You need a copy of The Home Workshop Dictionary

Drill bit

a rotating toolbit designed to make holes. Less accurate than a reamer, drills can typically produce a hole in a single pass, although see step drilling. For drilling metal most drills have two flutes and a end point at 118°. Each flute has two raised lands to reduce rubbing, and the tip is backed off at the end by grinding to give relief to the cutting edges.

Boring

The enlargement of holes with the use of an adjustable single point tool, rather than a sized tool (such as a drill or reamer). The forces on a boring tool are typically constant and in combination with the provision for making small, precise adjustments to the tool this means boring is preferred as a method of producing a very accurate bore.

[JasonBModerator @jasonb]

Posted by Ian Skeldon 2 on 14/07/2019 21:51:48:

So Jason, if I understand correctly, ………………………

That's it except I am driving the big bar with a MT4-3 adaptor and MT3 collet ( bar end turned to 3/4" as the chuck took up too much length, here it is in action

A couple more examples

[Ron LadenParticipant @ronladen17547]

Wow, those set ups in the three videos are impressive to say the least, great stuff.

Ron

[JasonBModerator @jasonb]

Thats all part of the fun, trying to work out ways to machine a part.

This is the 4th option that I mentioned of using a boring head in the lathe

 

 

And finally for those that say you can't swing out of balance items on the lathe

 

 

 

 

 

 

Edited By JasonB on 15/07/2019 07:35:14

[derek hall 1Participant @derekhall1]

Hi Bill

I have used between centres boring bars from boring out 30 inch diameter holes on the stern frames of ships, to holes less than an inch diameter on my little Myford lathe.

Between centres boring is easy, and accurate, but it does take a while and the hardest part is to set the job up to the lathe centre height and also clamp the job securely without distorting the cross slide or the job.

Regards

Derek

[BWParticipant @bw]

Thanks very much for all of the help and comments above, now I gotta read it all again and digest it a bit better.

Bill

[Mick B1Participant @mickb1]

Posted by JasonB on 15/07/2019 07:34:47:

Thats all part of the fun, trying to work out ways to machine a part.

…

 

And finally for those that say you can't swing out of balance items on the lathe

 

 

Edited By JasonB on 15/07/2019 07:35:14

Well, this isn't boring but interrupted-cut turning, but it's on a Webster-Bennett vertical borer, and it's a bit asymmetric…

https://youtu.be/WQ590wrFyRQ

 

It's an axlebox bearing shell for an A160 loco.

It's not my own setup or operation – work like that's too heavy, time-consuming and valuable for a volunteer like me… 

Edited By Mick B1 on 15/07/2019 19:54:08

[Vasantha AbeyParticipant @vasanthaabey64724]

boring on any machine tool , you must remember that if the work is held in a chuck 3 or 4 jaw, the chuck jaws should not be tightened too much, just lightly or else after you bore and remove the job, you will find the bore slightly bigger on the places where your chuck jaws were. This is due to spring back of the item after removal of clamping forces.

To correct you can hone the bore

If you bore on a mill with swivel head, unless the vertical spindle down feed is not used but table up feed is used, you can get an accurate bore. If you use the quill feed make sure that the quill is absolutely vertical to the table in Z axis by using a dial gauge to true the quill on both horizontal and vertical axis. If not the bore will be slanting to the error of the quill.

The boring tool should preferably made of a rigid carbon steel rod hardened and tempered to prevent vibrations. the tool cutting edge to have a very minute radius on the tip, approach angle of about 80 degree. To hone the hole what you can do is turn out a wooden shaft to about 1mm smaller than the bore, split the wooden shaft about 25 mm depth in the longitudinal axis, slip in a short strip of SiC abrasive grit 200 to 400 paper , roll it round the wooden pole and you got a honing tool. Use kerosene as honing fluid. Flush out regularly to get good finish.

Vasantha from Sri Lanka

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