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+--- Thread: Boring a Deep Hole (/thread-1509.html)
RE: Boring a Deep Hole - PixMan - 07-17-2013
Doing this on a mill with a boring head is certainly going to be "less risky" Ed. The piece can be done on a lathe, though you'll be running slow (under 500 rpm) to keep it from moving. There's going to be vibration from the out of balance condition.
What I forgot to ask is how many of these do you need to make? That's a big part of the decision too.
If you do this in the mill, do you have a boring head? If so, what diameter shank does that boring head use?
RE: Boring a Deep Hole - EdK - 07-17-2013
(07-17-2013, 06:23 AM)PixMan Wrote: Doing this on a mill with a boring head is certainly going to be "less risky" Ed. The piece can be done on a lathe, though you'll be running slow (under 500 rpm) to keep it from moving. There's going to be vibration from the out of balance condition.
What I forgot to ask is how many of these do you need to make? That's a big part of the decision too.
If you do this in the mill, do you have a boring head? If so, what diameter shank does that boring head use?
Ken,
I like the "less risky" aspect. I will be making one of these, assuming I don't screw up the first one.
I do have a 2" boring head. It takes 1/2" shank boring bars.
Ed
RE: Boring a Deep Hole - TomG - 07-17-2013
Ed,
That part isn't too long to just grab with a four jaw. Save the change of underwear for your boring adventures.
Doing it in the mill would require a larger boring head. If you tried doing it with a 1/2 bar and if you could find one long enough, it would probably sing like the church choir.
A boring bar held in the lathe would be a lot more rigid. Another option, just because there are many ways of doing this, would be to mount the block on a faceplate in the lathe. That would be even more rigid than a four jaw, and you could couterbalance it. Just a thought.
Tom
RE: Boring a Deep Hole - PixMan - 07-17-2013
Tough decision tree there Ed. I believe you should first try the mill, at least get the hole started that way.
Of course the lathe allows you use a larger boring bar, but that rigidity is lost when you have a workpiece flopping around.
I have had pretty good success over the years using boring bars that are larger then turned down for a short length to fit into a boring head. I agree that you really should have a 3" or 4" boring head that takes at least 3/4" bars. Check this photo and see the long bar in the middle with a turned down end. That bar has a 3/4" end diameter which fit into my crappy Chinese boring head and holds a 1/4" HSS or brazed carbide bit.
![[Image: IMG_0288-r-1-1.jpg]](http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/IMG_0288-r-1-1.jpg)
You want something similar. It's a quicky to make Ed, and cheap. Use the 1144 material you got.
RE: Boring a Deep Hole - EdK - 07-17-2013
(07-17-2013, 06:44 AM)TomG Wrote: Ed,
That part isn't too long to just grab with a four jaw. Save the change of underwear for your boring adventures.
Doing it in the mill would require a larger boring head. If you tried doing it with a 1/2 bar and if you could find one long enough, it would probably sing like the church choir.
Another option, just because there are many ways of doing this, would be to mount the block on a faceplate in the lathe. That would be even more rigid than a four jaw, and you could couterbalance it. Just a thought.
Tom
I've been wanting to get a 3" boring head for quite some time now so maybe this is the justification I need to finally pull the trigger. A 3" boring head takes 3/4" shanked boring bars thus reducing the choir decibels.
The faceplate idea is not a bad option also.
Thanks Tom!
Ed
RE: Boring a Deep Hole - PixMan - 07-17-2013
Strapping it to faceplate is good, though I find you never seem to have slots or fixing points in just the right place.
Funny is that I've got a 15" face plate in integral D1-6 mount which has never been mounted to the spindle. It still has the cosmolene on it.
The problem with a faceplate mounting is that you often add at least 1xD more to your boring bar length to get past the clamps.
RE: Boring a Deep Hole - EdK - 07-17-2013
(07-17-2013, 07:00 AM)PixMan Wrote: Tough decision tree there Ed. I believe you should first try the mill, at least get the hole started that way.
Of course the lathe allows you use a larger boring bar, but that rigidity is lost when you have a workpiece flopping around.
I have had pretty good success over the years using boring bars that are larger then turned down for a short length to fit into a boring head. I agree that you really should have a 3" or 4" boring head that takes at least 3/4" bars. Check this photo and see the long bar in the middle with a turned down end. That bar has a 3/4" end diameter which fit into my crappy Chinese boring head and holds a 1/4" HSS or brazed carbide bit.
You want something similar. It's a quicky to make Ed, and cheap. Use the 1144 material you got.
Ken,
Not a bad idea. I think you and Tom have hit on a good strategy to use the mill with a boring head suitable for the task. The quill stroke on my mill is rated at 5" but I'll need to verify that. I can always lower the head for the last bit if necessary.
Thanks guys!
Ed
RE: Boring a Deep Hole - TomG - 07-17-2013
Ken,
I have a faceplate that is littered with 5/16-18 tapped holes that works great for stuff like this, as you say the slotted type can definitely be a pain. It sounds like Ed needs to buy a new boring head.
Tom
RE: Boring a Deep Hole - doubleboost - 07-17-2013
You could always mount the job on the lathe cross slide and put the boring bar between centres
This is how I bore my engine cylinders
Use a big drill from the headstock first
![[Image: IMG_4161_zpse248be1d.jpg]](http://s261.photobucket.com/user/john970s0/media/IMG_4161_zpse248be1d.jpg.html)
![[Image: IMG_4149_zpscebdac07.jpg]](http://s261.photobucket.com/user/john970s0/media/IMG_4149_zpscebdac07.jpg.html)
![[Image: IMG_4175_zps627dc03f.jpg]](http://s261.photobucket.com/user/john970s0/media/IMG_4175_zps627dc03f.jpg.html)
![[Image: IMG_4174_zps8275743c.jpg]](http://s261.photobucket.com/user/john970s0/media/IMG_4174_zps8275743c.jpg.html)
![[Image: IMG_4122_zpsf3c83c52.jpg]](http://s261.photobucket.com/user/john970s0/media/IMG_4122_zpsf3c83c52.jpg.html)
John
RE: Boring a Deep Hole - EdK - 07-17-2013
(07-17-2013, 02:54 PM)doubleboost Wrote: You could always mount the job on the lathe cross slide and put the boring bar between centres
This is how I bore my engine cylinders
Use a big drill from the headstock first
John
Hi John,
I thought of that also. Isn't that called line boring?
I wondered how well it would work on a 1.5" hole. I thought that size hole might be too small for line boring, but I don't know.
Ed