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Jimno2506
02-15-2007, 01:49 PM
Machinists,

I have a project that requires me to make this wave on the outside of a 1.5" diameter and the inside of a 2.0" diameter steel part.

The wave amplitude is .015 and the length is .104" these are set in stone. Length is 1.00" The waveform is shown below.

http://www.lightningtimesavers.com/wave.jpg

Accuracy and repeatablity is crucial. Keeping +/- .001 will be paramount.

Material is 4140 HR. Qty up to 1000 pcs.

I would rather single-point this since there are no off-the-shelf concave and convex toolbits that fit my dimensions, although I'm sure I could have one made. Although I am concerned with chatter with this much cutter contact at the full profile.

Is there a way to make/buy a transfer-type guide (like cutting a house key) that I could use to move along the material via the compound?

Any other ideas are very welcome.

Regards,
Jimno

Swarf&Sparks
02-15-2007, 01:55 PM
Is the "wave" helical or circular?

Jimno2506
02-15-2007, 02:03 PM
The profile you see will make rings and/or grooves around the cylinder.

They are not helical.


Jim


edited to add: I will check with the designers to see if a thread pattern would work. Certainly makes this easier.

Swarf&Sparks
02-15-2007, 02:08 PM
ok, if you can't use threading techniques, at 1K parts, farm it out to a CNC shop

Jimno2506
02-15-2007, 02:10 PM
That takes all the fun out of figuring out how to do it. :(

Jimno

Optics Curmudgeon
02-15-2007, 02:14 PM
Who's fun would that be, you're asking us to figure it out.

Joe

Jimno2506
02-15-2007, 02:21 PM
How would you do it?

Thanks,
Jim

Ian B
02-15-2007, 02:21 PM
Small hydraulic copying attachment? :-)

Ian

Jimno2506
02-15-2007, 02:22 PM
Who's fun would that be, you're asking us to figure it out.

Joe


You are right. Forget I asked. I'll figger it out.

Jim

Swarf&Sparks
02-15-2007, 02:22 PM
get 25 quotes from CNC shops and take one just above the lower 3rd

Timleech
02-15-2007, 02:22 PM
Machinists,

I
Is there a way to make/buy a transfer-type guide (like cutting a house key) that I could use to move along the material via the compound?


Regards,
Jimno

Hydraulic copier?

Tim

Tin Falcon
02-15-2007, 02:42 PM
the normal method would be a pattern lathe or CNC. Do you have a taper atachment on your lathe ?? If so maybe you can use that to set up an improvised pattern atachment. thay is a lot of parts and 1 inch is a bit much for a form tool. Unless you can grind a tool for one cycle and repeat . Do you have a dro that can be set in incremental mode.? Sounds like you need acuracy and repeatability.
Tin

Peter N
02-15-2007, 02:48 PM
I think the others are right, for a run of 1000-off I would agree subbing it out to a shop with a CNC or copy lathe is the right the thing to do.

However, if you mad enough to want to them all yourself, then consider something like this:

http://nsa.kpu-m.ac.jp/gijutu/kousaku/easyweb.easynet.co.uk/chrish/profile.htm

I would have the template accurately wire-eroded (wire EDM) to shape from something pretty hard, as you will need a reasonably hard fine-pointed stylus as well to avoid wear.

Peter

CCWKen
02-15-2007, 03:00 PM
:rolleyes: Farm it out? Hogwash! But what would you expect from a "professional" HSM. ;)

I'd make a bit and cut the whole one inch at once. You're only going .015 deep. The biggest challenge is to make the bit. It's not any standard TPI in inch or metric so a single point would be easier but would take longer. Having access to a grinder would make it a piece of cake for the bit. For a thousand pieces, I'd make a bit and make some money! :D

Is there a spec for where the first and/or last "tooth" fall on the 1.00" length? (The .104" will be centered, offset?)

Jimno2506
02-15-2007, 03:04 PM
Unless you can grind a tool for one cycle and repeat . Do you have a dro that can be set in incremental mode.? Sounds like you need acuracy and repeatability.
Tin

Yep, that's exactly what I need. I've contacted a customer tool mfg and am awaiting a quote.

Incremental DRO is not available. I'll use micrometer stops and dial indicator for all movements.

If anyone here can grind this cutter for me I'd be happy to work with you.

Regards,
Jimno

John Stevenson
02-15-2007, 04:12 PM
Slack the spindle bearings off.
Adjust the play to get the right amplitude :D

That's the sort of finish all the lathes I have seen with bad bearings have :D

.

Peter N
02-15-2007, 04:25 PM
Slack the spindle bearings off.
Adjust the play to get the right amplitude :D

:D :D :D
Just choked on my coffee...

On a more serious note John, didn't you do something similar to the OP's requirement using coventry die inserts?
Was there much chatter, finish ok etc, or was that not a problem on the TOS or CVA?

Peter

Your Old Dog
02-15-2007, 04:28 PM
Who's fun would that be, you're asking us to figure it out.

Joe

ROFLMAO! :D

Jim Caudill
02-15-2007, 04:33 PM
Do you have access to a Hardinge HLV-H or TFB lathe? I have a tracing attachment that you could borrow that just might do it for you. You would cut/grind the profile in a blank (thus making your original key that you mentioned) and then allow the tracer to move along with the stylus following the template. By the way, if you'll edit your location in your profile, we can get an idea where you are.

John Stevenson
02-15-2007, 04:37 PM
:D :D :D
Just choked on my coffee...

On a more serious note John, didn't you do something similar to the OP's requirement using coventry die inserts?
Was there much chatter, finish ok etc, or was that not a problem on the TOS or CVA?

Peter

Peter,
If I was to do this myself I'd go the route you say and have a form tool wired from HSS.
But at a quantity of 2000 as he wants to do internal and external, it's labour of love.

I form turned those Poly V pulleys without chatter but they are quite deep at about 0.100" and the lathes in question are quite sturdy.

.

aboard_epsilon
02-15-2007, 04:39 PM
yeah farm it out

what ever method you come up with you're going to be pissed off after making two of em never mind 1000.

hardinge chuckers have thread following cam arrangement ...

bet with a little bit of alteration and imagination...bit of thought making it work across rather than down...and making a new style of thread doofer ...you could do this

All the best.mark

lynnl
02-15-2007, 04:54 PM
How long is the piece? If short enough, it would seem more suited to doing on a rotary table and an appropriately ground roughing type endmill.

Evan
02-15-2007, 04:59 PM
Make up a full width form tool using a single point form tool one wave wide. Turn the full width tool at 10 tpi with the single wave tool. Slice the full width tool axially (or grind it off) at the correct angle to produce a spacing of 0.104. I shall leave the math as an exercise for the reader. Harden tool and use.

I suggest using O6 tool steel. It has outstanding machinability, the best of all the tool steels.

pcarpenter
02-15-2007, 06:11 PM
I would think that "form tool", +/-.001", and "1000 parts" do not go together. The reason I say this is that I would think that an HSS form tool would need to be reground (very precisely) many times in 1000 parts??? I would also think your chatter alone might account for the .001 tolerance.

Am I crazy? Uh...wait....don't answer that. Is this realistic? Of course, realistic is not what this is about as "realistically" it makes the most sense to use a CNC lathe.

Paul

Magic9r
02-15-2007, 07:26 PM
Re-read Evan's post, he's talking about a circular form tool, you grind out a segment to give a cutting edge, when it wears you enlarge the ground out segment to give a new, perfectly shaped form tool & rotate to present the edge appropriately.
See Machinery's Handbook pre-CNC, each issue going back 20 or 30 years :D
Nick

Mcgyver
02-15-2007, 09:44 PM
put a shoulder bolt into to the top of threading dial to act as a crank pin that is connected to cross slide? kidding about bolting into the threading dial, but make something that works in a similar manner and is driven off the leadscrew. still, i agree with others, farm it out or convert the lathe - maybe just an encoder on the leadscrew driving a stepper on the cross feed (ie not full cnc)?

curious, what's it for and why such tight tolerances on this shape?

lane
02-15-2007, 11:00 PM
If you that hungry I pity you . Find a cnc shop farm it out.

LES A W HARRIS
02-15-2007, 11:32 PM
Parts Somewhat like this?
The .104" pitch, where does it start, crest or valley?

http://i37.photobucket.com/albums/e97/CURVIC9/07%20SHOPSTUFF/15by104a01.jpg


Circular form tool. (can be made with integral shank for easy holding, while sharpening).

http://i37.photobucket.com/albums/e97/CURVIC9/07%20SHOPSTUFF/15by104a02.jpg

Ian B
02-15-2007, 11:55 PM
Out of interest, what are these things that you're making?

Ian

John Stevenson
02-16-2007, 03:57 AM
I don't think people are saying it can't be done but at 2,000 who wants to be bothered ?

NickH
02-16-2007, 06:10 AM
John, I agree that I wouldn't want to produce 2000 manually, but the question asked was "How would you produce this on a manual lathe".
I'm sure the initial poster would find this a "Learning & Growing" experience,
Regards,
Nick

Evan
02-16-2007, 08:58 AM
If I actually had to do such a job I would use my manual lathe after converting it to CNC. :D

Jimno2506
02-16-2007, 10:55 AM
I'm looking into my taper attachment for possibilities.

The quantity is around 1000, not 2000 and that would be over about 6 months. Not one after the other after the other.

Les A W Harris has the concept down. But I'm not sure how you would get that into the part to begin with. The waves are opposite each other, interior wave starts at crest, exterior starts at valley.

I've got a quote <gulp> from a custom tool maker. The inside and outside cutters, one wave wide will cost me $380.00 HSS TiN coated.

My lathe will not handle a full width form tool.

I'll see if I can get someone local who can EDM me brazed carbide OD cutter and try it. If it works, I'll continue, if not, it goes to the CNC.

Regards,

Jim

ps: I cannot tell you what I'm making...yet, but if it works I'll let you know.

John Stevenson
02-16-2007, 11:42 AM
I've got a quote <gulp> from a custom tool maker. The inside and outside cutters, one wave wide will cost me $380.00 HSS TiN coated.

My lathe will not handle a full width form tool.

I'll see if I can get someone local who can EDM me brazed carbide OD cutter and try it. If it works, I'll continue, if not, it goes to the CNC.



That quote for tooling sounds about right.
If your lathe won't handle a full width form tool of this size and depth of cut it also won't handle an edm brazed cutter as they are also the same as form tools.

A machine that's not stiff enough to handle a form tool such as this will struggle to hold the tolerances you are seeking.

Sorry if it's not the answer you are seeking but the holy grail cost more than 10 cents.

.

Jimno2506
02-16-2007, 11:48 AM
John,

Won't a single-wave form tool require less strength/rigidity/horsepower to use than a full form tool? The single wave would be .104" wide and the full would be 1.000" wide. Seems like the considerable difference would make the single wave tool much like a radius cutter, which I have used on this lathe.

Regards,

Jimno

Ian B
02-16-2007, 12:58 PM
You'll be cutting 10 rings with the single wave form tool. How about making a saddle stop with 10 stops, each set for one ring?

Control the depth of cut with a cross slide stop or a dial gauge.

Ian

neonman
02-16-2007, 01:35 PM
jomno2506, I haven't read the whole thread, and don't know what precision you need. This being said, I would suggest making a mold and having them cast in the investment casting process. tou can get about any material you want, and should be able to hold tolerances to under .005.

neonman

Evan
02-16-2007, 01:49 PM
It sounds to me like a really tough way to make some money. If I were doing this for a living and a regular customer came to me with a job like this I would outsource it even if I didn't make a profit on it just to keep my customer happy. In the mean time you can be making money doing something within your capability.

Carld
02-16-2007, 01:54 PM
My opinion is you are wasting your time doing this job on a manual lathe. If you have a DRO on your lathe you might be able to do it with much trouble. If you think you can do it with a taper attachment I sure would like to know how you plan to do it. This is a job for a CNC lathe not a manual lathe. You can't compete with the CNC lathe. The full face cutter you mention having made will be hard to use without chatter. However if you insist on doing it good luck.

There is a big difference between realisim and wishfull thinking.