Author Topic: A smaller Boring and Facing head  (Read 6277 times)

Offline Graham Meek

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A smaller Boring and Facing head
« on: March 16, 2016, 09:18:56 PM »
I thought some of you might be interested in what has been happening in the Meek workshop over some of the winter months.

With a job looming which required some very tight tolerances to be held on the bores as well a machined location face around each bore, square to the bore. I decided it was time to design a new boring head that would more easily hold these tolerances. The head shown below is 50 mm diameter, unlike the previous design which had an intermittent radial feed when facing, this head feeds continually. Previous designs shown in the "Gathering of the Clan" photograph.

To get things more compact the feed dial is concentric with the main body. This has a zero setting facility and one complete revolution moves the tool slide 0.05 mm, which removes 0.1 mm off the diameter of the bore. Each numbered division represents 0.01 mm off diameter, while each sub-division is 0.002 mm off diameter.

The feed works in two directions which is dictated by the tool spacings in the tool slide. The direction of feed is selected by the knurled ring concentric with the feedscrew. Once the selection is selected this is locked by the M3 capscrew. Initially the selection is done using the 3 detent positions, which uses a spring loaded ball to locate each position. The neutral setting allows the feedscrew to be turned manually for initial setting up purposes. An Allen key is inserted into the M4 countersunk screw to make these adjustments. Because the M4 countersunk screw socket is normally not very deep this was drilled deeper and an hexagonal broach used to extend the socket, to give a better location. That way one 2.5 mm Allen key is used to carry out all the major functions on this head.

Because the direction of feed can be selected, the dial can always be used with the numbers ascending, something that was not possible with the earlier design.

The feed ring above the dial has an inbuilt clutch to allow the drive to the feedscrew to be stopped when the tool slide hits the stop. The head proved its worth in doing the job and is a useful addition to the shop, it will easily cover diameters up to 75 mm.

My best regards
Gray,

Offline Don1966

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Re: A smaller Boring and Facing head
« Reply #1 on: March 16, 2016, 10:08:14 PM »
Those are some fine looking boring heads Gray. Are you making the plans available?

Don

Offline cwelkie

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Re: A smaller Boring and Facing head
« Reply #2 on: March 16, 2016, 11:45:02 PM »
Graham - Very nice and well thought out improvements to an already excellent tool.

Here I was feeling negligent for not yet starting on my copy of your original design ... now, not so much in hope of an affirmative reply to Don's question above.  Would "pretty please" help?

Charlie

Offline 90LX_Notch

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Re: A smaller Boring and Facing head
« Reply #3 on: March 16, 2016, 11:51:03 PM »
Impressive as usual Graham.  Do you have any video of it in operation?  I would also be interested in building one.

-Bob
Proud Member of MEM

My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline petertha

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Re: A smaller Boring and Facing head
« Reply #4 on: March 17, 2016, 01:41:46 AM »
Very clean & impressive, Graham. A sub-division of 0.002mm... WOW! I would love to see the innards of the build one day, but I have a feeling it must resemble a watch.
I'm still a bit uncertain how the auto stop is set on your design. My only familiarity with these types of boring heads is confined to pictures of Wohlhaupter style where they have those 2 little T-clamps along the rail. Also, when yours is in auto-extend mode, does it click-click-click progress outward while holding the upper ring steady & then stops when released?

Offline Dave Otto

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Re: A smaller Boring and Facing head
« Reply #5 on: March 17, 2016, 02:07:00 AM »
Beautifully made tools Graham,

Thanks for sharing.

Dave

Offline Thor

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Re: A smaller Boring and Facing head
« Reply #6 on: March 17, 2016, 05:51:54 AM »
Hi Gray,

 Another excellent tool from your workshop.

Thor

Online Jo

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Re: A smaller Boring and Facing head
« Reply #7 on: March 17, 2016, 07:08:24 AM »
8)

Sexy would like to add one of those to his tool collection  :embarassed:

Jo
Usus est optimum magister

Offline Stuart

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Re: A smaller Boring and Facing head
« Reply #8 on: March 17, 2016, 07:19:07 AM »
Gray

I look forwards for more info and possibly drawings

Stuart
My aim is for a accurate part with a good finish

Offline Graham Meek

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Re: A smaller Boring and Facing head
« Reply #9 on: March 17, 2016, 10:33:14 AM »
Hello All,

Thanks for the compliments and I am glad you enjoyed the fruits of some of my labours. I am currently working on an article for Engineering in Miniature and I hope this will be published within the next few months if all goes to plan. The head is totally silent in facing mode, the typical click, click sound of these type of heads was made by my original design.  The two stops work in a similar way as the conventional boring heads found in industry.

The gears inside are 0.5 MOD and were all cut using single point profile cutters which were made in-house. These did represent something of a problem as they have small tooth counts and theoretically should have been hobbed, but I have found a way around this problem. The gears run extremely smoothly in operation and total backlash amounts to two numbered divisions on the dial, which amounts to 0.1 mm. Considering there are 6 gears in the train and a worm, I think that this came out very well.

The plans for the larger 66 mm diameter boring head shown in "the Clan" are in "Projects for your Workshop Vol 1" as well as a good descriptive text on how to cut dovetails painlessly. The smallest boring head in the clan is a half size version of this head but without the facing facility. The "Intermediate" head in the clan is just a 3/4 scale version of the larger one. As yet the drawings of this head are not available anywhere.

I am sorry no further information is available at the moment, the piece parts that the head was used on to manufacture are of a sensitive nature and the customer would not permit me to take any photographs. I do however have a job coming up on the Clayton Timber Tractor shortly which involves machining the reduction & transfer gearbox, this will need this boring head. Hopefully I can get some photographs then. (I have attached photo's of the engine build so far for this tractor).

My best regards
Gray,

Offline Stuart

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Re: A smaller Boring and Facing head
« Reply #10 on: March 17, 2016, 11:35:12 AM »
Thanks for the update Gray

if its going to be only in EIM please let us know so the relevant copies can be ordered

as a rule EIM repeat so much stuff it make having a sub a bit of a waste , I cite the D Hewson articles which are on there second performance ( note they are very good if you build loco's )


Stuart
My aim is for a accurate part with a good finish

Offline Graham Meek

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Re: A smaller Boring and Facing head
« Reply #11 on: March 17, 2016, 02:02:38 PM »
Hi Stuart,

As an author writing for the "Dark Side" is not really an option, unless I am are prepared to lose the copyright to the article. Although the basic fee for the article is higher, this does not offset the loss of the copyright. Which under such circumstances can be published for an unlimited number of times thereafter. EiM, and HSM for that matter, operate a more respectful way of going about publication in my view.

I do not know if you are aware, but there is a new Technical Editor at EiM. His approach from an author's point of view is completely different. The range of articles I am now being asked to write about  goes well beyond the workshop items, (although there are still a lot of these in the pipeline to be published each month).

At the end of the day any magazine can only publish the articles that are submitted. While I do not lean towards locomotives there are always some nuggets of information to glean for future use. A recent series of articles on silver soldering has helped my game no end. The only previous experience with silver soldering being while I was at school, 50+ years ago. The passage of time has not been good as regards what was learnt then about silver soldering, plus materials and techniques move on.

I will however keep you up to date.

My best regards
Gray,

Offline Stuart

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Re: A smaller Boring and Facing head
« Reply #12 on: March 17, 2016, 03:07:38 PM »
Thanks Gray

That explains matters from your side of the coin

Maybe a heads up as to when it's going to be published

Stuart
My aim is for a accurate part with a good finish

Offline Don1966

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Re: A smaller Boring and Facing head
« Reply #13 on: March 17, 2016, 04:49:48 PM »
Stuart the book has been published since 2012. Just do a search on line. RDG tools has it and Tee publishing has it. I just got my copy today.

Don

Offline crueby

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Re: A smaller Boring and Facing head
« Reply #14 on: March 17, 2016, 04:54:46 PM »
For those of us amateur machinists who don't know, could you give a brief description of what this head does different from a normal boring head like we use, where you set the diameter of cut and make a pass? Sounds like this is doing a lot more, but I am not sure what?

Thanks!
Chris