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View Full Version : Metal Lathes Taper turning attachment



Jerry Marcantel
06-01-2013, 2:54 PM
Has anyone ever made a taper turning attachment or have plans for one? It would be appreciated if you'd share ....... Thanks, Jerry (in Tucson)

Joe Watson
06-02-2013, 3:31 PM
If you search google for 'shop made taper attachment' you'll find a few.
Depending on what your doing, you can get by "turning between centers" using the tail-stock off center... works great.
Heres some MT3 blanks i made with that technique.
263605

If you unfamiliar with turning between centers, heres a quicky...

1) center drill both ends of the stock/martial you are working with.
2) Put a dead center in your chuck (or a piece of stock and turn a 30/60deg angle on it, to a point) - Home made dead center is my choice, once you take the time to make one, next time around you can just take a skim pass over it and you know its running 'true' and theres no need in trying to indicate it in.
3) Put a live center in your tail-stock
4) Put a "lathe dog (https://www.google.com/search?q=lathe+dog)" (store bought or home made) on one end of your martial.
5) Place your martial between the two centers, lathe dog side goes on the chuck end, leg of the dog sits against one of you jaws (this is how the martial is spun).
6) Off set your tail stock (side to side) to create the angle you want
7) Start cutting :)

There are other tricks people use (holding a milling boring bar head in tail stock (off setting the head) is one), to me the above is the simplest and turns the best results.

Good luck how ever you do it.

_

Jerry Marcantel
06-02-2013, 10:26 PM
Thanks for that info, Joe. I'm going to be making 10 live centers at MT2, and offset turning won't work. I've been all over the net looking for plans, but it's hard to determine what to do without actual demensions. And then lathe type. That's another story...... Thanks again.... Jerry (in Tucson)

Joe Watson
06-02-2013, 11:20 PM
.... I'm going to be making 10 live centers at MT2, and offset turning won't work....
Why not (unless your lathes tail-stock is fixed) ?
You could do it acouple different ways on a manual lathe.

If your tail stock is adjustable (and you have 15" of Z travel) and you feel like tossing around ideas.... ive been in the CNC trade for a number of years and can hold my own on a manual lathe, might be able to offer you some help.

Theres two main types of taper attachment's; both bolt to the lathes bed along with the cross-slide but one will use a telescoping lead screw for the cross-slide and the other you disconnect the cross-slides lead screw nut completely. Unless the lathe is equipped with a telescoping screw its much easyer to just disconnect the lead screw nut.

Maybe these links will help...
http://www.practicalmachinist.com/vb/general-archive/nardini-taper-attachment-please-explain-159707/
http://www.practicalmachinist.com/vb/monarch-lathes/taper-attachment-10ee-171651/index1.html
http://www.homemodelenginemachinist.com/index.php?topic=17656.0
http://www.practicalmachinist.com/vb/monarch-lathes/taper-turning-telescopic-leadscrew-159036/
http://madmodder.net/index.php/topic,2353.0/all.html

Have fun...

_

George Carlson
06-03-2013, 1:15 AM
A taper attachment has to be closely integrated with the lathe. Since you are saying offset tailstock will not work, it must be that you are chucking the work. I this case I would recommend using the compound. Set-up a know good MT2 and set the compound using a test indicator on the known piece. You should come out very close. You have never volunteered the lathe size or model, so it's going to be hard for anyone to give you any information that would be useful.

Jerry Marcantel
06-03-2013, 11:12 AM
George and Joe, I'm actually a cabinet maker turned woodturner, not a hobby machinist. I have invented this live center, and am trying to get some accurate samples made to send to a few catalogs to see about getting them sold. If you guys were to look at the bottom of the Metalworking page, you should see a post intitled, "I've been turning", posted by me. In it I think I show the first 5 live centers I made. I actually found all the info I needed to make the MT 2 off of youtube by TubalCain. I at the time didn't have the knowlege to make a TTA, but have now decided to go ahead and make one.
On the 5 LC's I made, I used the compound to get the angle. It worked pretty good, but I'm still off just a little. I since discovered play in the Y and Z. That has now been taken care of. BTW, the lathe is a Ta Shing Crown engine lathe, I think. It's a friends that has a welding/trailer repair shop that is so generous to let me use it and his Acra 2 knee mill for free. As the days go by, I learn more and more. It's now becoming fun to use his equipment. The tolerences of these 2 machine aren't exactly pristine, but they can get done what I need if I don't make any mistakes.
.
Joe, I heard bad things about turning off center. Mostly about wallowing/wallering the centers of the piece and also messing up the dead and live center points.. I don't think that would give me the accuracry I need. TAll the links you sent will help, but hat last link is what I'm looking for. There's enough information on that one that I can use. I'm not going to make one as fancy as his, but I think I can make the mods to fit the lathe I'm using. Thank you......... Jerry (in Tucson)

George Carlson
06-03-2013, 12:43 PM
OK now I see. If I were going to manufacture these things myself, I would find a shop with a good automatic CNC lathe to make the housings. A CNC can profile the entire outside in a single chucking. But, you would still have a piece that needed to be hardened and ground.
If I were wanting to make money and not go broke (after been in 40 years of engineering and manufacturing for 40 years), I would buy the interchangeable tip type live centers from asia and made, or have made, the cup tips.
263665
These kits can be purchased at retail for $60, wholesale at close the half of that.
BTW, One Way sells a cup point live center. It also has a threaded nose that will accept other accessories. Photo below:
263669

Joe Watson
06-03-2013, 1:38 PM
Jerry, i know nothing about patents or things like that, but you might want to check into that.

Not sure about the issues you brought up about turning between centers, outside of a CNC its one of the more accurate ways to machine a tapper (or a straight OD on a out of square machine). One nice thing about turning between centers is you can take he part in and out of the machine and there is no alignment problems (good for 2nd and 3rd operations when machining a part).
But, if you plan on doing production runs on a Manuel lathe (and a manual lathe that currently does not have or use a taper attachment), i can see an advantage of using the taper attachment, once you get it set, leave it set. With the tail-stock you will need to keep changing it, not a big deal, but will cost time.

If it where me and i was to do it on a manual lathe i would use the tail stock (and get (or make) a small tool post grinder.).
Center drill both ends (small #3 or #4 center drill not deep)
Machine the taper end.
Chuck on a taper socket (http://www.use-enco.com/CGI/INSRIT?PMAKA=214-8705&PMPXNO=945794&PARTPG=INLMK32) and finish the ID.
Get them hardened.
Toss on tool post grinder and put them back between centers (big dead center in the chuck this time since the ID has been opened up) and finish.

I would agree with George about the hardened and ground for the MT2 end, personally i would want that end to last as long as possible if i was to be selling this (being its not for personal use where you will be careful, people will get the shank all nicked up and then it will be "your" fault that it no longer locks into the tail-stock).

Dont know if you can draft in AutoCAD, but if you can, i would draw it up and look for a job shop with a CNC... If they have a lathe with a sub spindle, the whole thing can be machined complete, probably take around 7-9mins a part.... then hardened and ground.

If you to make a taper attachment, i would try my best to make sure every thing fits perfect... alittle slop/play here and there will make it a nightmare to use and get good results. For a taper attachment, the slop you found in your 'X' (cross-slide) will not matter if it was in the hand-wheel or screw, but if the gibs are loose (you can twist the cross-slide towards the chuck and tail-stock), you need to address that.

Ohh... if you do try and use the compound again (that must have been tough on a longer taper like that), locking the carrage might help, both the X and Z, on your last pass, finish the cut and unlock and pull away with out dragging the tool back down the part.

Good luck...

_

Jerry Marcantel
06-04-2013, 7:55 PM
George, the live center I'm making really doesn't have much to do with the cup tip, other than it's better than a point. It's a double duty live center. Check back after July 13th, in the "Turners Forum", and here also. That's the date I'm going to unveil the true purpose of this live center. I'm hoping others will have the same enthuasium I have after seeing it... It's definately something that's been needed in woodturning for a long, long time. I'm going out on a limb and say that in 50 years there won't be a lathe sold without one..... Jerry

Jerry Marcantel
06-04-2013, 8:27 PM
Jerry, i know nothing about patents or things like that, but you might want to check into that.

Not sure about the issues you brought up about turning between centers, outside of a CNC its one of the more accurate ways to machine a tapper (or a straight OD on a out of square machine). One nice thing about turning between centers is you can take he part in and out of the machine and there is no alignment problems (good for 2nd and 3rd operations when machining a part).
But, if you plan on doing production runs on a Manuel lathe (and a manual lathe that currently does not have or use a taper attachment), i can see an advantage of using the taper attachment, once you get it set, leave it set. With the tail-stock you will need to keep changing it, not a big deal, but will cost time.

If it where me and i was to do it on a manual lathe i would use the tail stock (and get (or make) a small tool post grinder.).
Center drill both ends (small #3 or #4 center drill not deep)
Machine the taper end.
Chuck on a taper socket (http://www.use-enco.com/CGI/INSRIT?PMAKA=214-8705&PMPXNO=945794&PARTPG=INLMK32) and finish the ID.
Get them hardened.
Toss on tool post grinder and put them back between centers (big dead center in the chuck this time since the ID has been opened up) and finish.

I would agree with George about the hardened and ground for the MT2 end, personally i would want that end to last as long as possible if i was to be selling this (being its not for personal use where you will be careful, people will get the shank all nicked up and then it will be "your" fault that it no longer locks into the tail-stock).

Dont know if you can draft in AutoCAD, but if you can, i would draw it up and look for a job shop with a CNC... If they have a lathe with a sub spindle, the whole thing can be machined complete, probably take around 7-9mins a part.... then hardened and ground.

If you to make a taper attachment, i would try my best to make sure every thing fits perfect... alittle slop/play here and there will make it a nightmare to use and get good results. For a taper attachment, the slop you found in your 'X' (cross-slide) will not matter if it was in the hand-wheel or screw, but if the gibs are loose (you can twist the cross-slide towards the chuck and tail-stock), you need to address that.

Ohh... if you do try and use the compound again (that must have been tough on a longer taper like that), locking the carrage might help, both the X and Z, on your last pass, finish the cut and unlock and pull away with out dragging the tool back down the part.

Good luck...

_

Joe, thanks for your input. Especially about making a live center in under 10 minutes on a CNC. That's gonna help when I get a quote back from Riten Industries one of these days. I don't think they're too interested.
I don't want to reveal too much about this center as I'm just now getting involved with a Patent attorney... I am going to reveal the center on 7-13 or just after.. It's been hinted at since January, but so far all I've done was PO a bunch of people in Turners Forum.
I've already made 5 working models. Got a bug in 2 of them, and probably other bugs in all of them. I think the way I set up the 3 bearings isn't exactly right, and will get with my local bearing house and see what they say about the arrangement. Two of the cup ring points weren't machined right as when I put the live center in my headstock and hold the nose, I get wobble... The other 3 are ok, but 2 bad out of 5 is not good odds. I need to figure out that problem. A machinist told me to make the whole thing in one chucking, rather that turn the nose, remove it from the chuck, turn it around, and then turn the bearing stud. At least I'm able to hold a pretty good tolerance. I can do .0005" most of the time, but mostly .001"

[/QUOTE] Ohh... if you do try and use the compound again (that must have been tough on a longer taper like that), locking the carrage might help, both the X and Z, on your last pass, finish the cut and unlock and pull away with out dragging the tool back down the part.[/QUOTE]=
I didn't know there is a lock for X. I'll have to look for it. I have the book on the lathe, but have you ever tried to read Engrish???? Lol. When I made my final pass on the taper, it was always downhill, in other words, going from .700 to .572. I left the number large by .005, and then sanded at high speed to clean up the tool marks, but that takes it back down to the minumun dimensions... I have a lot to learn. Thank you to you and George........ Ah"ll be bach........ Jerry (in Tucson)

Joe Watson
06-05-2013, 2:51 AM
....Especially about making a live center in under 10 minutes on a CNC. I dont want that to be misleading... I was refering to machining the main "housing/body"... hardening and ground/polishing would still need to be done along with the "tips".



A machinist told me to make the whole thing in one chucking, rather that turn the nose, remove it from the chuck, turn it around, and then turn the bearing stud. Yea... machining as much as possible in a single chucking is less error prone and keeps things square and concentric, but at times it can drag out the machining process, make it difficult to machine and run up the "labor" cost... Guess it really depends on what tools/machines a person has at there disposal.... with a four jaw chuck, you could get the "socket" running perfect (with in the accuracy of the indicator your using) and then the center's body can pop in and out of it just like you would do with a tail-stock. Run off 50-100pc of the taper end, then flip, send out to be harden, run off another taper end batch while waiting for the harden one to come back, pop the harden ones back in, grind, done. Just tossing out an option.



I didn't know there is a lock for X. I'll have to look for it.Normally its on the right side of the cross-slide and its just a screw that "pins" the gib against the dovetail. Dont think ive ever seen one which has a handle or "knob" on it like a "Z" does, but i have not see tons of manual lathes. I currently have an import 14x40 lathe in my basement (just got it brand new acouple months ago) that has a DRO, the glass scale for the X is mounted on the right side of the compound so i have "locked" it with "taper gib adjustor" on the face... really dont like doing it this way, but the DRO's scale has every thing all blocked up on the right of the cross-slide.



...When I made my final pass on the taper, it was always downhill, in other words, going from .700 to .572. I left the number large by .005, and then sanded at high speed to clean up the tool marks, but that takes it back down to the minumun dimensions... If your getting a good finish - "what works, works" :) Normaly you want to cut as the tool is designed for, "back dragging".


Dont know if this is part of your design or not, but a knurled OD (the biggest OD) would be nice so when a person goes to put the center in the tail-stock its easy to lock it in.


Will be looking out for the final product next month.

_

George Carlson
06-05-2013, 10:22 AM
Be careful of patent attorneys, they can suck you dry. First decide why you need a patent, is it to protect you intellectual property, or is it vanity? The attorneys really take advantage of folks with vanity patents. I have several patents, but big companies paid for them, not me.
Almost anything can be patented this is because a patent is not worth the paper it's written on until it's tested in a court of law. So if you are willing to pay what it takes to file the patent, you must be prepared to defend it.
My advice would be to file a provisional patent (you don't need an attorney, it can be filed on-line). This establishes you as the inventor. You then have a year (in the US) to file the regular patent paperwork. During this 12 months you can determine if it will be worthwhile to file a patent.

Jerry Marcantel
06-05-2013, 7:25 PM
Thanks George. I'm aware of those guys as I already have a patent issued back in '94. Cost $4000, but didn't have the money nor the resources to pursue it. I lost it when whe maintenance fees came due about the year 2000. So far, I haven't seen anyone making what I patented, so maybe it's just as good that I didn't pursue it. It has to do with shooting...
I just got my quote from Riten Industries back on making my centers..... $300 bucks..... I guess I'll have to make them myself, or head offshore to get them made.
Do you do woodturning??? If so, after 7-13 check in at the Turners Forum and look for my post on my live center..... That's when I make it public........... Jerry (in Tucson)