Author Topic: A smaller Boring and Facing head  (Read 6283 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

Offline Stuart

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Re: A smaller Boring and Facing head
« Reply #15 on: March 17, 2016, 05:01:56 PM »
Don

I have the book ,had it a long time that's where I found the dog clutch , working with Gray he produced a set of drawings for the big bore Myford
This is a new design smaller than the one in the book , I must say it sound the dog dangly bits


Chris
Hope Gray does not mind but it's a boring and facing head as you say it can bore , but it can face as well you hold the collar and it put on the cut itself . Hence a bore with a true face

They have many more uses

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 #16 on: March 17, 2016, 05:15:45 PM »
Hi Chris,

Here is an example of facing the cylinder barrel location face on a side valve engine square with the cylinder location hole. Plus a picture of the Old Boring and Facing Head to show the torque arm which makes the feed ring remain stationary while the head rotates. It is because this part is stationary that the boring head auto feeds.

Stuart,

No problem,

My best regards
Gray,

Online Jo

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Re: A smaller Boring and Facing head
« Reply #17 on: March 17, 2016, 05:55:03 PM »
Hi Chris, an automatic facing head has a gear on the screw that is used to adjust the bore diameter, the ring that is held stationary has a ratchet on it that engages in that gear each time it goes round. If the ring that is attached to the ratchet is held still then each time the head goes round it pushes the screw around a little bit so you get automatic feed.

Now you need some sort of stop that you can set and a clutch to prevent it going too far: So as the screw goes round it comes up against the stop and the clutch prevents the ratchet from pushing the adjusting screw any further round.


So an example: if you wanted an undercut in a bore you would poke your boring head in and adjust the stop to let the boring bar move outwards into the bore. Then you could under power bore down just like you would on a lathe, back to the top add a bit more under cut under power.... on you go. I have attached a few more examples of what you can do with one

Jo
Usus est optimum magister

Offline petertha

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Re: A smaller Boring and Facing head
« Reply #18 on: March 17, 2016, 06:23:22 PM »
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.
I had no idea a book was available. Found this link.But no delivery to Canada
http://www.amazon.co.uk/RDGTOOLS-Projects-your-Workshop-Graham/dp/B00S9SOJ1G

Found it in Tee. No international shipping info on website, anybody know?

I don't see available in Amazon N-Am but did see on ebay. What an oh-so-familiar bummer. Any recommendation as to how to procure to Canada?

Offline tangler

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Re: A smaller Boring and Facing head
« Reply #19 on: March 17, 2016, 07:19:41 PM »

Found it in Tee. No international shipping info on website, anybody know?


Have a look at "postage" under "Additional Information" at the bottom of the left hand bar on the TEE website

HTH
Rod

Offline crueby

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Re: A smaller Boring and Facing head
« Reply #20 on: March 17, 2016, 07:39:10 PM »
Hi Chris, an automatic facing head has a gear on the screw that is used to adjust the bore diameter, the ring that is held stationary has a ratchet on it that engages in that gear each time it goes round. If the ring that is attached to the ratchet is held still then each time the head goes round it pushes the screw around a little bit so you get automatic feed.

Now you need some sort of stop that you can set and a clutch to prevent it going too far: So as the screw goes round it comes up against the stop and the clutch prevents the ratchet from pushing the adjusting screw any further round.


So an example: if you wanted an undercut in a bore you would poke your boring head in and adjust the stop to let the boring bar move outwards into the bore. Then you could under power bore down just like you would on a lathe, back to the top add a bit more under cut under power.... on you go. I have attached a few more examples of what you can do with one

Jo

Thanks Jo - great diagram! Looks like an incredibly versitile tool, and one you could get into trouble with very quickly if not set up right!

Offline petertha

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Re: A smaller Boring and Facing head
« Reply #21 on: March 18, 2016, 12:36:20 AM »
Have a look at "postage" under "Additional Information" at the bottom of the left hand bar on the TEE website
HTH Rod
Missed that detail, thank you! Ordered!
« Last Edit: March 18, 2016, 12:47:15 AM by petertha »

Offline Graham Meek

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Re: A smaller Boring and Facing head
« Reply #22 on: April 03, 2016, 06:33:16 PM »
As promised a couple of photographs of the boring and facing head in use.

In the first photograph the boring head has sized the bore for the ball bearing race. Then using the automatic radial feed the bottom face of the bore was cleaned up and lastly, "caught in the act", facing the mounting face which bolts to the engine. Another cut has to be taken to reduce the flange thickness and clean-up the entire face.

The second photograph shows a similar facing operation under way, cleaning up the cover mounting face. I did try to fly-cut this face initially but the finish was awful, using the automatic facing facility produced a chatter free finish without any problem. Each individual face is cleaned up by stepping over the co-ordinates for each of the gear centres. The height setting remains constant throughout the operation and therefore all three faces are in the same plane. One more cut has to be taken to bring the flange thickness to the correct size and two more ball race bores have to be bored within the fabrication. This will ensure these bores are square to the cover face.

My best regards
Gray,