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View Full Version : X-axis vs. Y-axis feed rates -> newbee



rmatel
12-03-2001, 07:56 PM
The feed rate charts in both my Smithy's and an old Sears/Atlas's manuals show the cross-feed to be 10% to 12% of the in-feed rate. Is this normal with lathes and, if so, what is the reason behind it?

Thrud
12-04-2001, 01:51 AM
That is how it is geared in the apron which transfers power from the leadscrew or the power feed shaft (for those lathes that ONLY use the leadscrew for threading) up to the cross slide.

Dave

rmatel
12-04-2001, 07:38 PM
Yeah, but, what is the purpose for the difference? My asian powers both feeds from a slot/keyway in the leadscrew so the difference in gearing is on purpose.

Thrud
12-05-2001, 02:19 AM
Well, most lathes only have a few inches of crossfeed to begin with, if it ran at full speed you could bugger your cross slide leadscrew if it was set at high speed. Not the kind of thing you need to have happen by accident. Even at the fastest carrage feed it is easy to stop the cross feed over that short distance it travels - thus preventing inadvertent "Homer Simpson's". And it gives a nice smooth finish on face cuts...

Dave

halfnut
12-05-2001, 02:07 PM
I have usually seen 1/4 and 1/2 of longitudinal feed rates for cross slides, my Hendey is the same for both. Just depends on the whim of the maker, and to what gearing he can get to fit in the apron.

I like the arrangement on the Hendey the best myself.

Who knows the reasons why.

kap pullen
12-05-2001, 11:37 PM
i think the 1/2 feed rate on the crossslide is an economy measure.
on the old monarchs, pratt & whitneys
and others you could engage both feeds and cut one heck of a chamfer at 45 degrees.
now you can only feed one way at a time.
i dont know about hendys.
kapullen

halfnut
12-05-2001, 11:48 PM
Kap,

Yep, you can cut 45's with my Hendey. I've ran a Monarch and a Lodge and Shipley years ago, I think they did but I am not sure, slept since then.

snorman
12-06-2001, 05:06 AM
Yes on the Lodge and Shipley. Nice machines.

Thrud
12-07-2001, 03:30 AM
I wish I had room for a Monarch - seen a beauty on the net that was Navy surplus (just like new!) on a pallet for $17,500. I hate living in a rabbit hole...

Dave

kap pullen
12-07-2001, 08:54 AM
yep.
I served my lathe time on a war production board monarch in 1969. It had been run hard and put away wet. Good for heavy work but clumsey for model work. The double ee is a nice size for home shop. We have them at work.
Lodge and Shipley was a great heavy duty machine too. G & L , Warner & Swasey , and
King Boring Mills were wonderful machines.
Some of the new cnc stuff is good also.
A cnc mill is fabulus in the home shop. I've got a boss 6 b-port I picked up cheap.Thank goodness for cad calculating all them points.
It's done a lot of work on my Little Hustler locomotive still in process.
have fun machining, I do
kapullen

Thrud
12-08-2001, 02:53 AM
kap:

You number crunching animal, you! Does your wife know you snuck that in? I have been drooling on both a Haas (US) and Okuma (Japanese) but have no room at the moment. I hear the Kents (US) are not bad, but know little of them. It was surprising to me to find a Hardinge HLV-DR lathe (loaded) is about the same $$ as either of the two CNC mills.

Dave

kap pullen
12-08-2001, 04:52 PM
%
g0g75g90x0y0:
g1z.1f20.;
g83z1.z.1f3.0;
x0y0;
x1.y1.;
x-1.;
y-1.;
x1.;
g80g90;
x-2.y2.;
m25;
m2;
e
yep i bees a number cruncher.
Theys teaching me the mastercam at work,
but i crunches numbers at home.
It's a great machine but bridgeport dosen't
support these old machines very well. I had to buy two to get a good one(bad rck board). Cost $1200. with tooling, and flexawriter.
I guess i'm lucky finding old machines.
Been at it for thirty one years now(machining).
Happy machining
Kapullen

Thrud
12-09-2001, 06:02 AM
kap;

If you have a electronics tech school close to you talk to an instructor and see if they would repair the board for you. They usually need good projects to trip up the "keeners" in the class. Having a spare could be handy...

Dave

halfnut
12-09-2001, 09:20 AM
Kap,

Yuck, flexwriter. I don't have fond rememberances for one in particular. I think the tape reader was at fault actually. Was a 70's era Bridgeport series 1, later was involved in getting a series 2 up and running, it was modern and could have program punched in on controller.

One great thing about these older cnc machines is they still have boards that can actually be worked on.

G70
g90
m3
g0x2.99y0z.5
g1z.4f10
g2x0y-2.99i0j0f4
g1y-3.01f8
etc.
etc.

Shucks I forgot to put the little $ sign on end of each line, our editing program on PC requires it, don't know why. Sure do like that cable between PC and mill, we are even networked at work, can transfer programs all over, neato. They are even transfering cnc programs with palm computers now days.

Poor old rotary table sure gets neglected anymore since cnc.

Thrud
12-10-2001, 02:22 AM
I love it when you guys talk dirty...
Dave

kap pullen
12-10-2001, 08:41 AM
half nut
I'm really the dinosour at work.
These guys with their mastercam are fantastic. They can program a job in no time
and with no typos. In the old days we could blame the flexowriter for our mistakes.
Give me a devlieg or an old deckel and I'm just as happy.
Those guys wouldn't touch a turret lathe with a ten foot pole.
It's funny how quick you go from the young guy on the block to be the old man in the shop.
Hey you guys, build fast, we only have one lifetime.
happy machining
kapullen

halfnut
12-10-2001, 10:34 AM
Kap,

Hasn't been but 20 years ago and they called me the Kid. Those old fellers would still probably call me that today, they are all in their 70's and 80's now. Now I'm getting old and gray, working on becoming the grumpy old fart, got the grumpy part down pat.

Used to do battle with this CNC mill, 1-3 parts per program, ran up to 6 programs a night, got real good at editing programs. Your guys with mastercam sound like they are better than our programmers with e-pro, seems that they would get their stuff together, for a while programs running well, then things would just go to pieces, every program had problems, programmers would always blame it on the macros. I'd ask why did you change them, they would say they upgraded the software, upgrade my A, it worked before.

I'll give them some credit, did a full 3-D sample part out of alluminum while back, program was so big we had to break it up in 2 sections to load in controller. It ran with very few problems.

I could tell lots of stories about our programmers. Programming is just numbers and tool paths, then you have to do the fixturing.

I still like to drive a Bridgeport or lathe better than running the CNC, wasn't very long ago the only machinist jobs available were all CNC, we had an oversupply of manual machinists here. Those guys are now gone or drawing their rocking chair money, now places are looking really hard for toolmakers.

We are not totally dinasaurs yet.