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Re: chatter
Jerry Durand
Any machine tool needs to be adjusted when installed. The MM might be
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closer to working out of the box but I would still expect something to get tweaked in shipping. The heavier the machine, the more has to be done to it before you can use it. Things warp and such just moving the machine. A friend makes part of his living fixing brand new cars at car lots before they're sold the first time. So, it's not limited to just machine tools. On 02/12/2013 04:06 AM, MERTON B BAKER wrote:
Doesn't the MM catalog tell us that their lathes are carefully gone over and meticulously adjusted before they go out the door? Haven't read their catalog for a couple of years. --
Jerry Durand, Durand Interstellar, Inc. www.interstellar.com tel: +1 408 356-3886, USA toll free: 1 866 356-3886 Skype: jerrydurand |
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Re: chatter
Hi Bill,
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I have read what others have said and most of it is good advice. I had the same problem with my MM 7x16. The best thing I have done is to spring for a new pair of tapered roller bearings for the headstock. After changing out the headstock bearings and adjusting them up snug the problem was gone. I did a test cut last week on a piece of a 5/8" reamer shank which is machineable HSS. I chucked the piece in the three jaw chuck , spun it at about 1200 rpm and feeding with the carriage handwheel was able to easily remove .100" per side (.200" on the diameter) with absolutely no chatter. It cut like leaded screw stock. I you do this mod and set the bearings up snug you will see a vast improvement. Dick --- In 7x12minilathe@..., "Bill" wrote:
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Re: chatter
MERTON B BAKER
Doesn't the MM catalog tell us that their lathes are carefully gone over and meticulously adjusted before they go out the door? Haven't read their catalog for a couple of years.
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Mert -----Original Message-----
From: 7x12minilathe@... [mailto:7x12minilathe@...]On Behalf Of george curtis Sent: Monday, February 11, 2013 10:29 PM To: 7x12minilathe@... Subject: Re: [7x12minilathe] chatter my mm 16 was so loose it near clunked. weather cought up with me so not finished adj with shims. george ------------------------------------------------------------------------------ From: Michael Jablonski To: 7x12minilathe@... Sent: Mon, February 11, 2013 5:31:31 PM Subject: RE: [7x12minilathe] chatter Those set screws with the lock nuts are factory set, which means nothing depending on who set them at the factory. Mine were set correctly so I never needed to adjust them. If when you lift up on the front and rear of the carriage and it does not move, but the carriage can still slide the entire length of the bed freely, then the carriage is probably adjusted correctly. What you did was not a mistake, just a little extra learning experience. Michael - USA Micro-Mark MicroLux 7x16 -----Original Message----- From: 7x12minilathe@... [mailto:7x12minilathe@...] On Behalf Of William McBride Sent: Monday, February 11, 2013 5:13 PM To: 7x12minilathe@... Subject: RE: [7x12minilathe] chatter I have already changed the set screws with the lock nuts trying to get down to the 1 mil gap is that .001 inch? I have about .008 gap at front of saddle maybe .005 at back. I gave up spent a few hrs working on it needed to quit for tonight.The saddle moves very nicely seems to have no play haven't tried a cut yet. Did I make a mistake touching the set screws its very frustrating to adjust. Bill |
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Re: chatter
MERTON B BAKER
Probably, Bill. The reason the Wright brothers could fly their first
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powered airplane was that, unlike all the other would-be inventors, they were both experienced pilots, with many hours in the air flying similar machines as gliders. Further, they had both cracked up & repaired those machines several times, and knew a lot abut what to do and expect while in the air. I tried this learning method myself when learning to fly, and, just like the Wrights, found it both painful and expensive. I gave it up and took lessons in a machine with dual controls and a licensed IP. Much cheaper, & far safer. More fun, too. Same with lathes, but as you don't have to leave the earth, a lot safer & easier. You should have bought or borrowed, and read, at least 3 books on lathe operation, maintenance and toolmaking before buying a lathe; those I have now take up about 3 feet of shelf space. I had read only one, Igor Bensen's, before trying to learn to fly from the printed page. Others have done it, but I took the easy way out after the first expensive smash from an altitude of 3 feet. Now, about adjusting the gibs on the cross slide: You need a box end wrench to fit the locknuts, and an Allen wrench to fit the little screws. Loosen the locknuts, and all the screws, one turn. You should be able to run the cross slide back & forth the whole way with ease, and be able to wiggle it a bit with hand pressure. Center it on the carriage, tighen a central lock screw until the handwheel turns a bit stiffly, hold the screw STILL! with the Allen wrench, and tighten the locknut. The handwheel should turn now with much less resistance. Tightening the locknut backs the adjusting screw out just the right amount. Try this adjustment method a few times until you are familiar with what to expect, and the handwheel tension is there, but very slight. Gain experience. Run the cross slide back & forth over it's full range to check for uniformity. If all is satisfactory with the one screw adjusted, repeat the process with the others, working from the middle outward, and checking the full travel each time. The top slide is adjusted in the same way. We'll talk about the toolbit next. Mert -----Original Message-----
From: 7x12minilathe@... [mailto:7x12minilathe@...]On Behalf Of Bill Sent: Monday, February 11, 2013 7:29 PM To: 7x12minilathe@... Subject: [7x12minilathe] chatter Hi all I am a newbie , I am having difficulty with chatter even on light cuts. I am trying the tuning method explained in mini-lathe .com. I got a micro mark 7x16 lathe I have done a few light turning with it and went pretty well then I had to do a taper and thats when the problem began. I am having trouble adjusting the saddle mostly when I follow the instructions if I tighten the setscrews the saddle is very hard to move so obviously more than finger tight is too much does that make sense? Also the 1 mil it says to attain gap between ways and saddle would also make the saddle hard to move. I must be doing something wrong? Bill ------------------------------------ Yahoo! Groups Links |
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Opinion of Harbor Freight 8x12 lathe.
bob_guenthner
I've been looking for a mini lathe for a while. I put a wanted add on a local online site. I had a guy say he has the lathe in the subject line. Said he bought it about 8 years ago and hasn't used it much. I haven't looked at it yet, but would like some idea of price.
Any suggestions as to price are appreciated. Bob |
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Re: Ice maiden.
John Lindo
Simon thanks. I've sent Sarah a private e mail. Good luck with your new venture. Take care John L Spain
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Re: chatter
¿ªÔÆÌåÓý?Copper based alloys like brass and bronze require different tool bit geometry than tooling for other metals and plastics. In short, most materials - at least on these small lathes - will like some top/back rake so the sharp edge can slice into the material better, whereas tooling for bronze or brass should have zero back rake, as in flat topped. Brass doesn't slice or curly-Q away in a string like other metals or plastics, it kind of crumbles into a thick brass dust for lack of a better term. Once you see/hear/feel it machining right you will know what I am trying to describe.?I bet if you turn metal or plastic your chatter goes away. But you need a flat topped tool bit, i.e. zero back rake, special just for brass. Its just a whole different animal than steel, aluminum, plastic, etc. Those crappy lathe tools with the soldered on carbide tips generally suck on these little machines because they have no top rake and neither can they hold a sharp edge like HSS can. (Some of them even have a negative rake which only large machines with lots of power and rigidity can get away with using. They are useless on a mini-lathe though.) But with brass those cheap flat topped/zero back rake carbide tipped tools suddenly try to work pretty well. If you have some try one, it will at least work better than any tool designed for steel/aluminum/plastic. Brass/bronze is finicky, if there is any back rake the tool will repeatedly and rapidly dig in and break loose - chatter - and that sounds like what you are running into. Wrong tooling for the material at hand. ?I had a link to a web page that showed the basic turning tool geometries and also showed the flat topped tooling shapes ideal for brass, and so of course I cannot find it now. Hmmm. Hopefully somebody will recall what I am talking about and post a link. (?) ?Cheers, ?John Z., York, Pa. USA. On 2/11/2013 9:11 PM, William McBride wrote: ? |
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Re: chatter
my mm 16 was so loose it near clunked. weather cought up with me so not finished adj with shims.
?
george
From: Michael Jablonski To: 7x12minilathe@... Sent: Mon, February 11, 2013 5:31:31 PM Subject: RE: [7x12minilathe] chatter ?
Those set screws with the lock nuts are factory set, which means nothing depending on who set them at the factory.
Mine were set correctly so I never needed to adjust them.
?
If when?you?lift up on the front and rear of the carriage and it does not move, but the carriage can still slide the entire length of the bed freely, then the carriage is probably adjusted correctly.
?
What you did was not a mistake, just a little extra learning experience.
Michael - USA Micro-Mark MicroLux 7x16
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Re: chatter
I have very little experience with brass, but isn't it famous for
chatter if the cutting tool doesn't have NO top rake? In other words, the top of the cutting tool should be completely flat lengthwise? It sounds more like you have a problem with the tool. I'd try chucking up a scrap piece of mild steel and see if you still have chatter when turning that. If there's no problem, then it's probably tool geometry. Good luck! Charlie --- In 7x12minilathe@..., "John Best" wrote: [mailto:7x12minilathe@...] On Behalf Of William McBridetool post I am cutting 1" brass it is now chattering on all cuts not onlytapers even if I take off say .005 on a side as for rpm I don't know I haveno spindle tach. I tried speeding up the spindle got worse. |
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Re: chatter
John Best
¿ªÔÆÌåÓýTry changing cutting bits?? ? From: 7x12minilathe@... [mailto:7x12minilathe@...] On Behalf Of William McBride
Sent: Monday, February 11, 2013 9:11 PM To: 7x12minilathe@... Subject: [7x12minilathe] Re: chatter ? ? thanks John,Roy,Michael, The tool is on center I use a quick change tool post I am cutting 1" brass it is now chattering on all cuts not only tapers even if I take off say .005 on a side as for rpm I don't know I have no spindle tach. I tried speeding up the spindle got worse. |
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Re: chatter
William McBride
thanks John,Roy,Michael, The tool is on center I use a quick change tool post I am cutting 1" brass it is now chattering on all cuts not only tapers even if I take off say .005 on a side as for rpm I don't know I have no spindle tach. I tried speeding up the spindle got worse.
Bill |
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Re: chatter
John Best
¿ªÔÆÌåÓýHi Bill, The problem began when you got into a taper??? Hmmm.? Well, I wouldn¡¯t go straight for the gibs.? I¡¯d look at the tool geometry, that it¡¯s set on the centerline, your cutting speed and the depth of cut to make sure all that¡¯s reasonable for the metal you¡¯re cutting.?? For reference, let¡¯s have your metal and the diameter you¡¯re turning, then we can get the feeds and speeds out of the way.? When you mentioned the taper, I thought about depth of cut varying, which started me thinking ¡®back to basics¡¯. ? By the way, I have had a Micromark 7x14 for almost 5 years now.? Not too much tune-up was required, though I did find a QCTP (Quick Change Tool Post) let me get the tools set a lot faster than shimming them.? That¡¯s where my money is at present (with the scant data at hand), that you¡¯re cutting below center.? ? John B ? From: 7x12minilathe@... [mailto:7x12minilathe@...] On Behalf Of Bill
Sent: Monday, February 11, 2013 7:29 PM To: 7x12minilathe@... Subject: [7x12minilathe] chatter ? ? Hi all I am a newbie , I am having difficulty with chatter even on light cuts. I am trying the tuning method explained in mini-lathe .com. I got a micro mark 7x16 lathe I have done a few light turning with it and went pretty well then I had to do a taper and thats when the problem began. I am having trouble adjusting the saddle mostly when I follow the instructions if I tighten the setscrews the saddle is very hard to move so obviously more than finger tight is too much does that make sense? Also the 1 mil it says to attain gap between ways and saddle would also make the saddle hard to move. I must be doing something wrong? |
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Re: chatter
Look at the underside of the bed; there are sometimes globs of paint that have to be removed to provide a clean path for the slide plates to travel. If that's not a problem, the easy way to adjust the slide plates is with the lathe off its base, turned upside down! Personally, I don't think the clamp/jack screw arrangement scales down well from larger machines - I used shims & eliminated the jack screws.
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If you want to keep the clamp/jack screw arrangement, use the clamp screws to make the carriage slightly stiff to slide. Then, use the jack screws to slightly free it up. You'll need to be careful; the slide plates are brittle, too much jack screw pressure can fracture them. (That's why I went with shims.) The theory is that the jack screws provide enough force to keep both sets of screws from vibrating loose. Check your tool height; a tool that's a little high will chatter. Roy --- In 7x12minilathe@..., "Bill" wrote:
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Re: chatter
¿ªÔÆÌåÓýThose
set screws with the lock nuts are factory set, which means nothing depending on
who set them at the factory.
Mine
were set correctly so I never needed to adjust them.
?
If
when?you?lift up on the front and rear of the carriage and it does not
move, but the carriage can still slide the entire length of the bed freely, then
the carriage is probably adjusted correctly.
?
What
you did was not a mistake, just a little extra learning experience.
Michael - USA Micro-Mark MicroLux
7x16
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Re: chatter
William McBride
I have already changed the set screws with the lock nuts trying to get down to the 1 mil gap is that .001 inch? I have about .008 gap at front of saddle maybe .005 at back. I gave up spent a few hrs working on it needed to quit for tonight.The saddle moves very nicely seems to have no play haven't tried a cut yet. Did I make a mistake touching the set screws its very frustrating to adjust.
Bill |
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Re: Hello from Yellowknife
yea..
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machspace wrote: @ajawamnet |
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Re: chatter
¿ªÔÆÌåÓý?
Hello Bill,
?
The following on adjusting the carriage gibs assumes
that you are using a properly sharpened tool bit, all the angles are
correct,?it is set to the proper height, and that the gibs on the cross
slide and compound are properly adjusted.
?
There
are six cap screws that you use to adjust the carriage gibs. Three are located
on the back side underneath the carriage. The other three are located under the
front side of the carriage but they are behind the apron. These adjustment cap
screws are pretty sensitive. On my machine, I only used my fingers to make the
cap screw adjustments. No Allen wrench was needed. If you snug them up a bit too
much,?the carriage will be too tight and will bind. If they are
too?loose, then the cap screws may vibrate out and fall onto the chip tray.
?
When I
ran into the problem of the cap screws vibrating out, I removed the carriage and
cleaned any oil out of the screw holes, and cleaned the threads on the cap
screws. Then I put a little GE silicone sealer on the threads to act as a little
thread locker. This held them from loosening up again, but made them easy to
remove or adjust again if needed.
?
One
way to gain access to the front cap screw adjusters it is to remove the apron.
This is done by removing the two large cap screws that attach it to the
carriage. Make a note, maybe?even take?picture of the location of
these cap screws for the apron before removing them. The holes are over sized to
allow for alignment adjustment. (When you reassemble try to get them close to
where they were)
?
Gently
slide the apron carefully out of the way. It?will not fall off
because?the split nut will hold it to the lead screw. If leaving the
apron on the lead screw presents a problem then you will need to remove the
right side lead screw pillow block bracket so you can slide the apron off the
lead screw. If you do this, you will have to re-align both the apron and right
side lead screw pillow block. Not a big deal.
?
Also
make sure to remove the thread dial indicator so it does not inhibit the
movement of the apron.
?
You
should now?be able to slide the carriage back and forth on the bed as you
adjust the front and rear cap screws. The carriage should slide easily without
binding, but you should not be able to feel any?slop when lifting up on the
front or rear of the carriage.
?
Don't
mess with the two set screws along with their lock nuts which are located
between the cap screws. Doing so will make for much more work. Others will tell
you remove them all together and shim the gibs but I don't think that this is
necessary on a new lathe. (Others will disagree) See section 3 of the assembly
instructions.
?
Make
sure the split nut (power feed lever) is engaged before retightening the apron
cap screws to the carriage so the apron is properly aligned. This is covered in
section 4 of the assembly instruction from
Micromark.
?
You
may also want to remove the back splash to gain easier access to the rear
carriage cap screw adjusters.
?
If the chatter continues after the carriage gibs
are adjusted, you can isolate the compound and cross slide gibs by first
tightening the compound's gibs so it is locked down. If the chatter continues
then tighten down the cross slide's gibs and see if the chatter goes
away.
Michael - USA Micro-Mark MicroLux
7x16
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chatter
Bill
Hi all I am a newbie , I am having difficulty with chatter even on light cuts. I am trying the tuning method explained in mini-lathe .com. I got a micro mark 7x16 lathe I have done a few light turning with it and went pretty well then I had to do a taper and thats when the problem began. I am having trouble adjusting the saddle mostly when I follow the instructions if I tighten the setscrews the saddle is very hard to move so obviously more than finger tight is too much does that make sense? Also the 1 mil it says to attain gap between ways and saddle would also make the saddle hard to move. I must be doing something wrong?
Bill |
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Re: Hello from Yellowknife
¿ªÔÆÌåÓýOpps,
I guess you did say in the subject line that you are in Yellowknife,
Canada.
My
mistake.
Michael - USA Micro-Mark MicroLux
7x16 ? |
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