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Reducing diameter cylinder bobs

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Bazyle26/10/2020 17:16:08
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Havn't read the article yet but imagining a larger felt bob as used for car part polishing I would try to slice it from the end using a craft knife blade sloped down at a steep angle - like you might try and cut a paper circle on a faceplate. Ie just cutting not normal turning.

JasonB26/10/2020 17:37:12
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Well I just tried it on a Dremel one and cut no problem with my usual brass tool. Your biggest problem will be finding one on a small enough shank if you want 3/32" dia and to still have some felt left.

Edited By JasonB on 26/10/2020 17:38:09

Oldiron26/10/2020 18:12:54
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Posted by Michael Gilligan on 26/10/2020 16:46:11:

.

Edit: If only we had a McMaster-Carr outlet in the UK .

Try here Michael:- MSC Industrial supplies

regards

Michael Gilligan26/10/2020 18:52:19
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Posted by Chris TickTock on 26/10/2020 16:58:03:

Your not reading the same pages as me Michael, look at page 41 there is a picture with words below;

[…]

Shall we just leave it as a don't know and say no more about it?

.

Sorry, Chris : I can’t do that ^^^

If the tool is round-nosed ... This must be a very bad picture:

f72fdb3a-a790-44eb-858e-c3c998c09231.jpeg

.

MichaelG.

Michael Gilligan26/10/2020 19:34:13
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Posted by Oldiron on 26/10/2020 18:12:54:
Posted by Michael Gilligan on 26/10/2020 16:46:11:

.

Edit: If only we had a McMaster-Carr outlet in the UK .

Try here Michael:- MSC Industrial supplies

regards

.

Thanks for that ...

Are they the same products ?

... and does MSC handle the whole of the magnificent McMaster-Carr catalog (sic) ?

I will be absolutely delighted if they do !!

MichaelG.

JasonB26/10/2020 19:36:53
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But would you see a 0.2mm radius on the tool in that photo? that's what radius I have on my brass tool

Michael Gilligan26/10/2020 20:00:54
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Posted by JasonB on 26/10/2020 19:36:53:

But would you see a 0.2mm radius on the tool in that photo? that's what radius I have on my brass tool

.

Perhaps ‘round nose’ is open to interpretation [two nations separated by a common language ?]

but it looks, to me, like a truncated triangle ...which may well have rounded rather than sharp corners.

... Frankly, I’m past caring

MichaelG.

Chris TickTock26/10/2020 20:06:30
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wonderful and interesting posts gentlemen

Chris

JasonB26/10/2020 20:08:28
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More rounded when use das a L/H tool than a right but as it's only a 5/32" tool it was probably rounded with a couple of licks of a slip stone

rounder2.jpg

 

As I mentioned they seem to cut OK, bit larger dia at the end which was probably the unsupported end deflecting away from the tool and I expect the Dremel ones are possibly not as dense or hard as better ones.

Edited By JasonB on 26/10/2020 20:08:50

Edited By JasonB on 27/10/2020 07:11:49

Edited By JasonB on 27/10/2020 07:12:33

Steviegtr26/10/2020 20:54:57
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Is that video for private members only,. Does not work.

Steve.

Michael Gilligan26/10/2020 23:18:06
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Posted by JasonB on 26/10/2020 20:08:28:

[…]

but as it's only a 5/32" tool ...

.

Really ?

I found the full picture on p100 and assumed they were 1/4”

... the shank looks to be soft, and there’s an obvious bruise from the clamping screw [which, being Sherline, I presume to be 10-32]

MichaelG.

JasonB27/10/2020 07:25:55
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Does it work now Steve?

Looks like they are 3/16" from this, thought I saw 5/32" mentioned elsewhere. Also mentions the HSS used.

Ron Laden27/10/2020 07:36:51
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Yes the video works OK Jason.

Ron

Michael Gilligan27/10/2020 08:25:02
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Posted by JasonB on 27/10/2020 07:25:55:

Does it work now Steve?

Looks like they are 3/16" from this, thought I saw 5/32" mentioned elsewhere. Also mentions the HSS used.

.

Really sorry to labour this, Jason, but :

(a) Your video shows successful cutting yes with what appears to be an insert ... does it have zero top-rake ?

and (b) Your referenced document also mentions 1/4” blanks, so I’m really none-the-wiser about what our hero was actually using.

MichaelG.

.

JasonB27/10/2020 09:01:23
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1. As I said it cuts OK with "my usual brass tool"

2. It also says that the tool on the right of the photo is 3/16" and this is the same tool that is in the enlarged extract of the photo I posted yesterday which is same width as the rounded one.

But for any doubters here it is again being cut with an 3/16" square HSS tool, definately rounded and with zero or possibly even slight negative top take, As I said in previous post the felt deflects where the steel shank does not go right to the end and tears out a bit at the end of the cut but the section inbetween looks usable. Chris's biggest problem will be finding something mounted on a shank that is less than his desired 3/32" dia.

And here is why I use an insert on brass, it saves having that shower of small chips go all over the place and also saves having to keep another set of tools just for brass when the insert will also Aluminium and bronze.

 

 

Edited By JasonB on 27/10/2020 09:07:51

Michael Gilligan27/10/2020 09:50:45
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Posted by JasonB on 27/10/2020 09:01:23:

[…]

But for any doubters here it is again being cut with an 3/16" square HSS tool, definately rounded and with zero or possibly even slight negative top take, […]

.

Many thanks for taking the trouble to do that, Jason yes

I am not so much a ‘doubter’ as a ‘seeker of clarity’ ... so the closer we can get to the conditions that Chris quoted, the happier I will be.

MichaelG.

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