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Boring heads

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Michael Gilligan25/10/2018 19:48:05
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Posted by Alan Vos on 25/10/2018 18:31:41:
Posted by Ron Laden on 24/10/2018 19:19:20:
I hope ******* is not what I think it may be Alan, but I will assume it isnt.

What I had in mind is described by Channel 4 as "relatively inoffensive and its inclusion, even in a programme watched by large numbers of children, would be unlikely to offend most viewers."

.

What I find very strange is that Channel 4's webpage on this topic appears to be freely accessible to the previously innocent eye:

[Warning: those of a sensitive disposition should probably not follow this link] : **LINK**

https://www.channel4.com/producers-handbook/ofcom-broadcasting-code/protecting-under-18s-and-harm-and-offence/offensive-language

MichaelG.

Howard Lewis25/10/2018 22:10:20
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Recently, I need a 2 inch diameter hole in some 1/2 inch thick Aluminium.

Admittedly, it was done in the lathe with a 1.5 hp motor, at 90 rpm, but I used a 1.75 inch diameter hole saw. White Spirit or Neatcut as lubricant, and frequent withdrawal to clear the swarf.. The hole was then bored to size, with a CCMT0604 tip in 8mm dia boring tool. Cuts were 0.020" maximum, with final cuts being "spring cuts".

The holesaw may tax your 500 W motor, but many pistol drills had no larger a motor, years ago, and they drove holesaws. Don't force it, ( keep the cuts shallow) lubricate, and clear the swarf frequently. To arrive at finish size, even from 1.75 inches, took a little time, but a lot less than trying to take umpteen 0.020" cuts from 1/2".

Look at the work that has been produced on ML7s; apparently beyond its capabilities!

As the saying goes "Slowly, slowly catchee monkey" Most of us are on a hobby, not piecework!

Howard

Ron Laden26/10/2018 10:46:12
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Just about to order a boring head set from ARC, comes with a carbide tool set, would anyone know if the tips come sharpened. I dont have a green wheel yet and when I received a set of tipped tools for the mini lathe (not from ARC) they were cut to shape but not blunt.

Ron

John Haine26/10/2018 10:54:01
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Some time back I had to cut a 4" hole in 1/8 aluminium plate for a flue. I used a boring head in my VMB and made a trammel cutter with a length of 1/2" silver steel going through the transverse hole and a 1/8" HSS bit mounted in a cross-hole near the end of the bar and ground to a narrow oarting-tool like edge at the end with lots of side clearance. Ran the machine at lowest speed and very slow feed, went through OK but I did have a couple of jams.

Neil Wyatt26/10/2018 10:58:39
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Posted by Ron Laden on 26/10/2018 10:46:12:

Just about to order a boring head set from ARC, comes with a carbide tool set, would anyone know if the tips come sharpened. I dont have a green wheel yet and when I received a set of tipped tools for the mini lathe (not from ARC) they were cut to shape but not blunt.

Ron

I believe they are, but call Arc to check.

It's often necessary to relieve the front face anyway if you want to use them in smaller holes.

Neil

JasonB26/10/2018 11:01:01
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They do come sharpened but none will be ground correctly for use in the side holes. You may want to just touch them up with a diamond slip but will need to grind then for use in the side.

Ron Laden26/10/2018 11:03:35
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Thanks guys

Ron

ega28/10/2018 18:01:02
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Posted by Alan Waddington 2 on 25/10/2018 08:36:07:
Posted by ega on 24/10/2018 23:46:07:
Posted by not done it yet on 24/10/2018 22:01:25:

Apart from the fact that the Rotabroach type of cutter has flutes for chip clearance it has the added advantage that it cuts closer to size and, further, a pilot is not necessary so that the resultant slug has no central hole.

A pilot isn’t necessary with a hole saw either, if mounted in a drill press or mill, infact you can even use them freehand without the pilot drill if you use some form of jig to centre.

Thanks for the tip about pilotless centre drills. I tried this today with a 74mm hole saw on some 3mm plastics sheet; undemanding material but I was impressed by the ease of the operation.

ega28/10/2018 23:10:51
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PS I meant to say pilotless *hole saws* (and the one in question was actually 70mm diameter.

Ron Laden31/10/2018 17:06:00
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I am confused which is quite the norm for me, please see picture below.

My boring head set arrived and all of the tools are right hand tools, assuming I,ve mounted the tool correctly it needs to be run in reverse/anticlockwise when in the side/horizontal position. The tools are fine in the vertical but I dont have reverse on the mill just clockwise so unless I am being stupid or missing something how can you use these tools on a forward running machine. Or should the tool be turned through 90 degrees clockwise until the bit is inverted..?

dsc06179.jpg

Edited By Ron Laden on 31/10/2018 17:31:58

Howard Lewis31/10/2018 17:45:51
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For all the jobs, so far, the actual Boring tool has been mounted vertically, rather than horizontally, as shown, BUT the holes have not been 100mm diameter! (Possibly beyond the limit for vertical mounting?)Which ever way the tool is mounted, use the shortest one possible, to maintain rigidity.

The orientation of the tool, not just the speed, may affect whether chatter occurs.

I can see no immediate problem with mounting the tool "inverted", other than needing more clearannce under the job, to allow the tool to pass through the work piece.

For accurate sizing, the final cutS need to be Spring cuts. In a 25mm deep cut, it would not be impossible to see some taper, otherwise.

Howard

JasonB31/10/2018 18:24:43
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Ron as I said earlier

"They do come sharpened but none will be ground correctly for use in the side holes. You may want to just touch them up with a diamond slip but will need to grind then for use in the side."

Don't try running these boring heads backwards as they can unscrew from the arbor.

Having said that they can't be used on the side hole there is infact a way that you can use the cutters that you have. Rotate the tool shown in your photo 180degrees and then cut upwards from the bottom of your plate to the top.

Ron Laden31/10/2018 19:00:38
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Thanks Howard/Jason

I think it a bit strange, disappointing and to be honest bloody annoying that they supply the head with "wrong handed" tools when you consider most of the smaller mini-mills have no reverse. Wouldnt you have thought they would come with tooling to suit clockwise operation and then they could be used on all the mini-mills and all the models going up in size.

As it is if you have a non reversing mill then the supplied tooling is not correct for normal operation.

Ron

SillyOldDuffer31/10/2018 19:49:04
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Posted by Ron Laden on 31/10/2018 19:00:38:

Thanks Howard/Jason

I think it a bit strange, disappointing and to be honest bloody annoying that they supply the head with "wrong handed" tools when you consider most of the smaller mini-mills have no reverse. Wouldnt you have thought they would come with tooling to suit clockwise operation and then they could be used on all the mini-mills and all the models going up in size.

As it is if you have a non reversing mill then the supplied tooling is not correct for normal operation.

Ron

Hard to think of a use for a left-handed boring bar apart from in the cross hole!

Most boring is done from the bottom of the head because there's less risk of chatter. Sideways mounted boring of large holes is rare in my experience. The few times I've done it, boring bottom up as Jason describes.

Avoid running a boring head or anything else with a screw fixing in reverse. Don't ask how I know...

Dave

JasonB31/10/2018 20:08:02
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It's correct for 99% of use where the tool tends to be used pointing downwards and as a lot hear said the smaller mills would not have the power to use the head with the tools sideways for bigger holes why would they be supplied with tooling that may not get used. Though it would be nice if one of the nine cutters were LH but as i said the supplied RH one scan be used to upcut should the need arrise.

Another alternative if you don't have a green grit wheel is to make up a simple 12mm dia adapter to take a bit of 6mm or 1/4" HSS from an old ctr drill or milling cutter and grind that up on a standard wheel.

Ron Laden31/10/2018 20:11:20
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Posted by SillyOldDuffer on 31/10/2018 19:49:04:
Posted by Ron Laden on 31/10/2018 19:00:38:

Avoid running a boring head or anything else with a screw fixing in reverse. Don't ask how I know...

Dave

No danger of that Dave, I have no reversefrown

Ron Laden31/10/2018 21:33:29
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Posted by JasonB on 31/10/2018 20:08:02:

It's correct for 99% of use where the tool tends to be used pointing downwards and as a lot hear said the smaller mills would not have the power to use the head with the tools sideways for bigger holes why would they be supplied with tooling that may not get used. Though it would be nice if one of the nine cutters were LH but as i said the supplied RH one scan be used to upcut should the need arrise.

Another alternative if you don't have a green grit wheel is to make up a simple 12mm dia adapter to take a bit of 6mm or 1/4" HSS from an old ctr drill or milling cutter and grind that up on a standard wheel.

Points taken Jason but I still dont understand why the tooling supplied only suits machines with reverse for using the tool sideways. Most of the tooling supplied wont get used if you have a non reversible mill as I do. There is 9 tools in the set why they couldnt have supplied 3 of them as a short, medium and long in LH I dont know. Sorry, just a bit pee`d off with how they have thought out the tool set.

 

 

Edited By Ron Laden on 31/10/2018 21:34:32

Simon Williams 331/10/2018 22:12:58
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Posted by Simon Williams 3 on 25/10/2018 09:28:05:

I forgot to note that the boring tool used in the head axially is a right handed tool, but the tool needed for the radial position is a left handed tool, as it cuts on the opposite edge.

Ron - good evening,

Good to hear you've decided to buy the tool and have a go, and not so good that you've found the left hand pitfall. Obviously running the tool backwards isn't an option - the mandrel on which the head is mounted is screwed in with a right hand thread so running the tool backwards will simply unscrew the thread.

I never thought of running the tool bottom to top - how do you adjust the diameter with the tool below the work using the radial hole? Maybe it's just keyhole surgery?

I feel it's a bit unfair to criticise the tool supplier for not including at least one left handed tool in the kit. You're into advanced boring head using, and fettling a suitable tool is an exercise for the student. I dare say most purchasers of one of these boring head kits of tools would send the left hand tool back saying it's been made wrongly!

Good luck and do let us know how it goes, Would love to see a video - or at least some piccy's of work in progress, ideally with a view of how the tool is sharpened ant presented to the work piece.

Simon

Mark Elen 131/10/2018 22:52:38
117 forum posts
201 photos

Ron,

I wasn’t happy with using mine (same arc kit) on Ali, so I bought a SCLCR 12mm bar with an Ali insert. You could get an SCLCL (left hand bar) and do similar. Have a look here: **LINK**

Cheers

Mark

John Reese01/11/2018 02:29:05
847 forum posts

A square tool bit works nicely in the cross hole in the boring head. You can grind the tool to optimize the tool performance. It is also a lot cheaper than insert tooling.

A major problem with the small variable speed machine is very poor torque at low speeds. If the machine has a back gear or multi step pulley system it can be work well at lower speeds.

I am not familiar with the motors and controls on these machines but I would assume the available horsepower diminishes as the motor speed is reduced. If the motor has a cooling fan reducing the speed will also result in less air passing through the motor and increasing the potential for overheating,

The 100 mm hole is probably possible if one has sufficient patience. If I were to try to do the job I would probably get in a hurry which would result in smoke escaping from the motor.

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