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through bore
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Hi John,
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Ah yes, the grey matter's working today. I just searched the archives and recalled sufficient key words (reamer+chris). Check out message 18553. John --- In 7x12minilathe@..., "John" <botmom@...> wrote:
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You can open it up to 13/16". In the "links" section of the 7x10 group
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there's something for "Al's Reamer", since it was Varmint Al who started the whole thing. There are a couple of reamers circulating around from user to user. Chris (of LMS fame) provides adult supervision to keep things moving. Roy --- In 7x12minilathe@..., "John" <botmom@...> wrote:
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jumbo75007
This is probably a stupid question, buy why is a reamer used for this
operation and not a drill? All that is done is to open up the hole. An exact concentric hole is nice, but is it really necessary? The idea is for a 3/4 inch rod to pass thru. There is probably a good reason, but my "hammer and screw driver as a prybar" mentality is not seeing it. Thanks in advance, Dan Fuller Carrollton, Texas --- In 7x12minilathe@..., "roylowenthal" <roylowenthal@...> wrote: group there's something for "Al's Reamer", since it was Varmint Al who |
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Dan wrote........This is probably a stupid question, buy why is a reamer used for this operation and not a drill? All that is done is to open up the hole. An exact concentric hole is nice, but is it really necessary? The idea is for a 3/4 inch rod to pass thru..........
Or a 21mm drill, slightly larger. Ellis |
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Dan:
A drill would work just as well as a reamer. Regards, Chris Wood LittleMachineShop.com <> The premier source of parts and accessories for mini lathes and mini mills. 396 W. Washington Blvd. #500, Pasadena, CA 91103 (800)981-9663 * Fax (626)797-7934 ________________________________ From: 7x12minilathe@... [mailto:7x12minilathe@...] On Behalf Of jumbo75007 Sent: Wednesday, April 04, 2007 12:00 PM To: 7x12minilathe@... Subject: [7x12minilathe] Re: through bore This is probably a stupid question, buy why is a reamer used for this operation and not a drill? All that is done is to open up the hole. An exact concentric hole is nice, but is it really necessary? The idea is for a 3/4 inch rod to pass thru. There is probably a good reason, but my "hammer and screw driver as a prybar" mentality is not seeing it. Thanks in advance, Dan Fuller Carrollton, Texas --- In 7x12minilathe@... <mailto:7x12minilathe%40yahoogroups.com> , "roylowenthal" <roylowenthal@...> wrote: group there's something for "Al's Reamer", since it was Varmint Al who |
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A reamer takes less power to drive. For making the hole, a drill
would do just as well, except a 13/16" drill bit requires more torque than the lathe can deliver; that's why drill bits cut more aggressively than reamers. Roy --- In 7x12minilathe@..., "jumbo75007" <fullerdj@...> wrote: this operation and not a drill? All that is done is to open up thehole. An exact concentric hole is nice, but is it really necessary? Thea prybar" mentality is not seeing it.circulating around from user to user. Chris (of LMS fame) provides adult |
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jumbo75007
AHH, good explaination. I understand the reason now.
Thanks, Dan Fuller Carrollton, Texas --- In 7x12minilathe@..., "roylowenthal" <roylowenthal@...> wrote:
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Victoria Welch
On Wednesday 04 April 2007, jumbo75007 wrote:
AHH, good explaination. I understand the reason now.Me too, thanks! --- In 7x12minilathe@..., "roylowenthal"-- Victoria Welch, WV9K/7 "Follow orders? No chance. Orders are for those who don't know what to do, and that isn't my problem." -Lt(jg) Morgan Wolfe |
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Hi Dan,
No such thing as a dumb question - unless you don't ask it! In that vein, I'll ask my dumb question. If you have a 7x12 lathe, why do you need to enlarge the spindle bore to fit 3/4" through? The off- the-shelf bore is 20mm so you have very nearly 1mm to spare. Do you have a burr or am I missing something? John --- In 7x12minilathe@..., "jumbo75007" <fullerdj@...> wrote: <roylowenthal@> wrote:drill torquewould do just as well, except a 13/16" drill bit requires more than the lathe can deliver; that's why drill bits cut more |
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Roy wrote..........A reamer takes less power to drive. For making the hole, a drill would do just as well, except a 13/16" drill bit requires more torque than the lathe can deliver..........
I'm not sure this is the full story. Reamers are fed at a much lower rate and cutting speed. If a drill was fed at the same or slower rate, then the cut could be made. HTH Ellis |
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The practical problem is controlling the feed of a large drill
enlarging a hole; they tend to self feed at their spiral rate. It's easier to control a reamer's feed. Roy --- In 7x12minilathe@..., "Ellis Cory" <ellis103@...> wrote: hole, a drill would do just as well, except a 13/16" drill bit requires more torque than the lathe can deliver.......... rate and cutting speed. If a drill was fed at the same or slower rate, then the cut could be made. HTH |
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Reaming it provides a smooth bore & ensures it's actually as big as
it claims to be. Roy --- In 7x12minilathe@..., "born4something" <ajs@...> wrote:
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Roy wrote.....The practical problem is controlling the feed of a large drill enlarging a hole; they tend to self feed at their spiral rate..........
I believe this is only true with lever operated machines, such as drill presses. Using the screw operated tailstock and only opening up by 1/64" at a time should be very little problem. If necessary, the lips could be 'backed' off in the same fashion as brass drills. Of course, the quill travel is limited, so it's a case of drilling a bit, move the tailstock a bit. HTH Ellis |
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G'day Ellis
Drilling from the tail stock is OK but the drill or chuck is held by a taper. If the drill self feeds it breaker its grip with the taper and slips. An exercise in futility. You have to keep cutting pressure om the drill and the drill takes over so you can't restrict the feed rate. A reamer is the way to go. Note that machine reamers have straight flutes whilst hand reamers have spiral flutes. One good turn deserves another. Regards, Ian --- In 7x12minilathe@..., "Ellis Cory" <ellis103@...> wrote: large drill enlarging a hole; they tend to self feed at their spiral rate.......... drill presses. Using the screw operated tailstock and only opening up by 1/64" at a time should be very little problem. If necessary, the lips could be 'backed' off in the same fashion as brass drills. Of course, the quill travel is limited, so it's a case of drilling a bit, move the tailstock a bit. HTH |
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Ian wrote.....If the drill self feeds it breaker its grip with the taper and slips.......
This only happens if the forces are excessive. The depth of cut on each lip will be less than 8 thou. The rate of feed is entirely depepndant on how slow you turn the handle. The flute angle (rake) can be overcome by grinding a flat each lip, as for drilling brass. This is the way I have done many jobs without the drill pulling out. The last one opening up a hole to 1.25 ". Reamers are very expensive for a one off job. You could try and get on the Varmit Al's reamer queue, or just buy a 13/64" drill and DIY. HTH Ellis |
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From experience, it's still a problem. With a TS mounted drill, it'll
still try to self feed, either jamming the machine or popping the chuck out of the TS taper. With a carriage mounted drill, it'll still try to pull itself in. The reamer did a nice job, with no drama:-) Roy --- In 7x12minilathe@..., "Ellis Cory" <ellis103@...> wrote: large drill enlarging a hole; they tend to self feed at their spiral rate.......... drill presses. Using the screw operated tailstock and only opening up by 1/64" at a time should be very little problem. If necessary, the lips could be 'backed' off in the same fashion as brass drills. Of course, the quill travel is limited, so it's a case of drilling a bit, move the tailstock a bit. HTH |
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andyf1108
I wonder if it would it be possible to make up a boring bar, with a
short front section "A" of a diameter which is a sliding fit inside the spindle, then a length "B" of smaller diameter carrying the tool bit, and then a short section "C" which is a sliding fit at the "opened out" diameter which the bit will cut. With the spindle turning, push this boring bar through it with the tailstock centre (some sort of dog would be needed to stop the bar rotating, and the cut would have to be in stages, to allow the tailstock to be moved between stages) Section A would centre the bar in the spindle at the beginning of the cut, and B would be of such a length that, by the time A emerged from the spindle, section C would have entered the bore and take over the centring job. Or would this, too, tend to self-feed and pull the bar away from the tailstock centre? Cheaper than a reamer, though, and a big drill would need a big chuck, unless it had a Morse taper shank to fit the tailstock. Andy --- In 7x12minilathe@..., "roylowenthal"[Non-text portions of this message have been removed] <roylowenthal@...> wrote: it'll still try to self feed, either jamming the machine or popping thechuck out of the TS taper. With a carriage mounted drill, it'll stilltry to pull itself in. The reamer did a nice job, with no drama:-) |
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You'd actually be better off with a suitably large conventional
boring bar. A regular boring bar will ensure that the spindle bore is concentric with the axis of rotation. As a generality, the carriage is preferable to the TS for accurate, controllable tool holding. The virtue of the reamer is that it's quick & available for the cost of postage! Since the bore can be reamed, it's not a big enough cut to justify (to me) the nuisance of setting up a boring bar. Then again, I did mine a few years ago, when the community was smaller. Roy --- In 7x12minilathe@..., "andyf1108" <andyf1108@...> wrote: inside the spindle, then a length "B" of smaller diameter carrying thethe tailstock centre? |
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andrew franks
Yes, that's got to be right, Roy. I was just thinking aloud. Enlarging the calibre of my spindle isn't on my project list, though if it was, I doubt if the official Guardian of the Reamers would let one of them travel to the UK all on its own!
Andy roylowenthal <roylowenthal@...> wrote: You'd actually be better off with a suitably large conventional boring bar. A regular boring bar will ensure that the spindle bore is concentric with the axis of rotation. As a generality, the carriage is preferable to the TS for accurate, controllable tool holding. The virtue of the reamer is that it's quick & available for the cost of postage! Since the bore can be reamed, it's not a big enough cut to justify (to me) the nuisance of setting up a boring bar. Then again, I did mine a few years ago, when the community was smaller. Roy --- In 7x12minilathe@..., "andyf1108" <andyf1108@...> wrote: inside the spindle, then a length "B" of smaller diameter carrying thethe tailstock centre? --------------------------------- What kind of emailer are you? Find out today - get a free analysis of your email personality. Take the quiz at the Yahoo! Mail Championship. |
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