Boring bars

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Boring bars

This topic has 20 replies, 9 voices, and was last updated 12 January 2022 at 14:58 by Robin.

Viewing 21 posts - 1 through 21 (of 21 total)

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8 January 2022 at 18:03 #579293
bernard towers
Participant
@bernardtowers37738
I have just noticed some nice boring bars on our favourite auction site. They are Armstrong pattern and I personally have never seen them before. Looking carefully it would seem to be an interesting concept especially as a toolmaking project.
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8 January 2022 at 18:03 #20570
bernard towers
Participant
@bernardtowers37738
Armstrong pattern boring bars
8 January 2022 at 21:15 #579321
MikeK
Participant
@mikek40713
I'm not familiar with the Armstrong pattern, but I did make bars based on a YT video by Stefan Gotteswinter:

One at 90 degrees and one at 45 degrees. Easy enough for me to make, but the 45deg digs in when boring *into* a hole, because of the cutting bit angle.

Edited By MikeK on 08/01/2022 21:18:13

Edited By MikeK on 08/01/2022 21:34:19
9 January 2022 at 06:52 #579354
Michael Gilligan
Participant
@michaelgilligan61133
Armstrong made some excellent tooling … 1947 catalogue here: **LINK**

https://pounceatron.dreamhosters.com/docs/misc/Armstrong-Catalog-THB49-1947.pdf

MichaelG.

.

P.S. __ There is a wealth of interesting information on that site

https://pounceatron.dreamhosters.com/docs/

Edited By Michael Gilligan on 09/01/2022 07:11:59
9 January 2022 at 08:37 #579363
DiogenesII
Participant
@diogenesii
Please can we have a picture or a link – (shouldn't be a problem unless the seller is some offshore budget tool warehouse) then we can see what is different about them.. ..hard to have a discussion otherwise..
9 January 2022 at 08:44 #579364
Michael Gilligan
Participant
@michaelgilligan61133
DiiogenesII

I don't know exactly what bernard is considering, but : If you search ebay for ‘armstrong boring bar’ you will find several listings … all similar to designs shown in the catalogue that I linked.

MichaelG.

Edited By Michael Gilligan on 09/01/2022 08:45:04
9 January 2022 at 11:34 #579400
Dave Halford
Participant
@davehalford22513
These holders all fit either lantern style posts or need a clamp making. I think they are forged.
9 January 2022 at 23:32 #579485
bernard towers
Participant
@bernardtowers37738
Yes I would think they are forged but what I found interesting was the clamp arrangement, looks much stronger than the usual grubscrew on most offerings and not too difficult to make. Also infinite angling of the tool bit

Edited By bernard towers on 09/01/2022 23:33:23
10 January 2022 at 07:04 #579500
Jon Lawes
Participant
@jonlawes51698
Stefan Gotteswinter is a really cracking engineer, I do enjoy seeing his work.
10 January 2022 at 07:43 #579502
JasonB
Moderator
@jasonb
I'm not seeing why they should be forged. Looks like they are just a bar cross drilled for the tool bit, drilled and tapped at 90deg to that and then a slitting saw cut at a shallow angle. Should be possible to remove the screw and slide them into a round holder.

e-bay listing

Edited By JasonB on 10/01/2022 07:49:21
10 January 2022 at 08:07 #579504
Michael Gilligan
Participant
@michaelgilligan61133
Posted by JasonB on 10/01/2022 07:43:11:

I'm not seeing why they should be forged. Looks like […]

.

Is that the listing in which the O.P. was specifically interested ?

MichaelG.
10 January 2022 at 08:18 #579506
JasonB
Moderator
@jasonb
Don't know Michael but searching e-bay for "armstrong boring bar" I can't see any bars that look to be forged ( or forged ones in your link). The comment about better than a grub screw would also make these a candidate as there is more thread engagement and a bigger hex which would be an advantage.

Unless you have found something else?

Edited By JasonB on 10/01/2022 08:22:12
10 January 2022 at 08:27 #579507
Michael Gilligan
Participant
@michaelgilligan61133
I was just wondering, Jason [for the sake of clarity]

Armstrong used several designs of bar, and a pretty wide range of holders.

MichaelG.

.

Ref. pages 9 to 12 of the catalogue which I linked previously.

Edited By Michael Gilligan on 10/01/2022 08:41:52
10 January 2022 at 08:32 #579508
JasonB
Moderator
@jasonb
Just have to wait for Dave and Bernard to say what they were looking at.
10 January 2022 at 08:43 #579510
Michael Gilligan
Participant
@michaelgilligan61133
10 January 2022 at 10:49 #579538
Dave Halford
Participant
@davehalford22513
I'm talking about these, more properly boring bar holders, they will take round HSS or the boring bars above

Plus a normal Armstrong tool holder.
10 January 2022 at 11:35 #579553
ega
Participant
@ega
Posted by JasonB on 10/01/2022 07:43:11:

I'm not seeing why they should be forged. Looks like they are just a bar cross drilled for the tool bit, drilled and tapped at 90deg to that and then a slitting saw cut at a shallow angle. Should be possible to remove the screw and slide them into a round holder.

e-bay listing

Edited By JasonB on 10/01/2022 07:49:21

I looked at that listing at the outset and couldn't see how the bar itself would be held.

Thanks for your drawing; the arrangement looks superior to the usual grub screw.
10 January 2022 at 15:22 #579598
Michael Gilligan
Participant
@michaelgilligan61133
Posted by ega on 10/01/2022 11:35:32:

[…]

I looked at that listing at the outset and couldn't see how the bar itself would be held.

Possibly with the clamp illustrated on p12 of the catalogue

MichaelG.
12 January 2022 at 10:22 #580023
ega
Participant
@ega
MichaelG:

Thank you for your suggestion. It's hard to say from the p12 illustration whether the bars shown there are the same as those in the eBay listing I found. I had to guess which one was intended and hit on this: https://www.ebay.co.uk/itm/165230578628?hash=item2678828bc4:g:5uAAAOSwpbNhtl8T

If a closed holder were used with the eBay bars I thought that the cutter and clamp might first have to be removed. The p12 holder makes this unnecessary,of course. But the eBay bars appeared to be heavily stamped along most of their length which seemed likely to compromise their stability as the raised lettering would prevent perfect contact with the holder. I realise this may not be a problem in practice and hoped that someone with experience of them would comment.
12 January 2022 at 12:48 #580056
Michael Gilligan
Participant
@michaelgilligan61133
Posted by ega on 12/01/2022 10:22:41:

[…]

… hoped that someone with experience of them would comment.

.

Me too … I have exhausted my knowledge of the matter

MichaelG.
12 January 2022 at 14:58 #580078
Robin
Participant
@robin
As instructed I was looking at that auction place at ARMSTRONG No.10 BORING BAR AND TOOL HOLDER. Didn't look very interesting until the pic of him holding it in his big, hairy, American hand.

It's a monster. I like monsters, especially when it comes to boring bars
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