[4]

Shaper cross feed increments

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

jwmay

Active Member
Active Member
Joined
Dec 3, 2017
Messages
141
Likes
140
#1
Hello all,

Does anyone see any pros or cons of changing the cross travel lead screw to something a little less random? I’ve got an Ammco 7” shaper and the cross travel leadscrew is 1/2-13. I’m not saying I WANT to do it. But it occurred to me that a 1/2-20 would be a little easier (possible) to cipher on. I don’t think they chose 13 tpi arbitrarily, but I can’t come up with a really good reason why. Probably something to do with the ratchet mechanisms diameter and tooth count. So anyhow, I’m free writing here it seems. What do you say? Any thoughts?
 

f350ca

Active User
H-M Supporter-Donating Member
Joined
Jul 11, 2013
Messages
1,556
Likes
2,755
#2
That sounds like a really odd pitch for a lead screw, 2 mm pitch is close, sure its not a metric pitch one that someone has installed before you.

Greg
 

projectnut

Active Member
Active Member
Joined
Apr 14, 2014
Messages
384
Likes
251
#3
I guess I don't understand the need to change the cross feed screw. The feed is currently adjustable from .003" to .018" per stroke. Here's a excerpt from page 2 of publication 27-100, "Delta, Milwaukee, AAMCO 7" Precision Shaper for Metalworking" manual. This is the 1950 version of manual PM-1737.
"The feed is a reversible and adjustable type. One tooth on the ratchet is equal to a cross feed of .003". By adjusting the position of the T bolt S80-16 in the feed adjusting lever S80-3 a feed varying form .003" to .018" can be obtained"

There are several versions of manual PM1737. I have a newer version published by Rockwell that gives a bit different explanation of the adjustments. This later version makes the assumption the operator already has a working knowledge of the machine. It highlights the range and how to read the scale on the rocker arm.

Here's a link to the Rockwell Publication on the Vintage Machinery.Org website:
http://www.vintagemachinery.org/pubs/detail.aspx?id=3662
 

jwmay

Active Member
Active Member
Joined
Dec 3, 2017
Messages
141
Likes
140
#4
There isn’t any need. But assuming I was cutting a .050 wide by .050 deep slot. Assuming I could even do it once without a dial, how could I get back exactly .050 to my starting point? .050 divided by 13 tpi, which equates to something like .077 revolutions of the handwheel. Versus a 20 tpi leadscrew where .050 becomes exactly one revolution of the hand wheel. Now make it a 1/2” slot. Hmm...6.49 revs of the handwheel on a 13 tpi leadscrew. Well that’s not so bad. I guess the obvious answer is to mount a dial indicator with a mag base. This shaper doesn’t have a graduated dial on the cross feed. Or if it does, the graduations have faded. Anyhow that’s what made me start thinking about it. But truly there’s no “need”. Actually, since you forced me to do the math, it’s not looking like such a problem anymore. Just looking for group input.

On the subject of the manual: It’s funny how they worded the bit about changing feed direction. Stating how to change feed direction, and following it up with a recommendation to ensure the table is feeding during the correct portion of the stroke. As it happens, anytime you change feed direction, you must also change the orientation of the feed eccentric which dictates when the table moves. So they tell you it’s one easy step to change feed direction. But oh by the way, it’ll be feeding on the cut stroke now, so change this other thing too, if you happen to notice. It probably took me 20 minutes to figure out why it was cutting all wonky when it was headed left, but just fine going right. Ha!
 

projectnut

Active Member
Active Member
Joined
Apr 14, 2014
Messages
384
Likes
251
#5
Here's another version of the PM-1737 manual that came with the machine. This one was printed in 1951.

http://www.lathe.com/catalogs/DeltaMilw7ShaperInstrGS.pdf

I guess I never thought of changing the lead screw, mostly because like you suggested I mount an indicator to the base and just watch the knee progress. When it gets within a few thousandths of my goal I disengage the auto feed and manually feed it to the desired width
 

Attachments

4GSR

Iron
Former Member
Joined
Aug 8, 2011
Messages
0
Likes
12
#6
Wonder why they didn't put a typical 1/2-10 Acme lead screw on the shaper as you would find on others?
 

f350ca

Active User
H-M Supporter-Donating Member
Joined
Jul 11, 2013
Messages
1,556
Likes
2,755
#7
Now thats really interesting. I never thought about having to change the orientation of the feed eccentric when you change directions but yes it makes sense. Guess I've been feeding on the out stroke half the time and never noticed. Thanks
Really why 13 but Dave an I were discussing why 8 tpi. My down feed is that so 125 divisions on the dial. Would it be they used more fractions as in 1/8th of an inch when my shaper was built, Possibly 20's or 30's.
Greg
 

projectnut

Active Member
Active Member
Joined
Apr 14, 2014
Messages
384
Likes
251
#8
Now thats really interesting. I never thought about having to change the orientation of the feed eccentric when you change directions but yes it makes sense. Guess I've been feeding on the out stroke half the time and never noticed. Thanks
Really why 13 but Dave an I were discussing why 8 tpi. My down feed is that so 125 divisions on the dial. Would it be they used more fractions as in 1/8th of an inch when my shaper was built, Possibly 20's or 30's.
Greg
I don't believe there was any "standard" at the time. Somewhere along the line someone in the design department picked 5, 8, 10, 13, or whatever. It got approved, went into production, and is now part of history. I have several machines in the shop with different pitch lead screws. My Sheldon lathe cross feed screw has an 8 pitch. Making one full revolution of the dial .125". The Seneca Falls lathe has a 10 pitch cross feed screw making one full revolution .100", and the AMMCO shaper has a 13 pitch lead screw, making one full revolution .077". The Bridgeport has a 5 pitch lead screw making one full revolution .200"

Now you know why I don't take a beer with me when I go to the shop.
 

Downwindtracker2

Active User
Active Member
Joined
Sep 5, 2014
Messages
243
Likes
95
#9
My shop built shaper has 1/2 x13 as well. I assumed it was an easy size to tap . I've got a 100 division dial, thank you Grizzly, and a 1/2 x10 acme redi-rod for the new feed when I get back to that project. For the down feed I've got a 50 division dial and 7/16x20 redi-rod.
 

C-Bag

Ned Ludd's bro
H-M Supporter-Premium Member
Joined
Feb 9, 2017
Messages
338
Likes
257
#10
There isn’t any need. But assuming I was cutting a .050 wide by .050 deep slot. Assuming I could even do it once without a dial, how could I get back exactly .050 to my starting point? .050 divided by 13 tpi, which equates to something like .077 revolutions of the handwheel. Versus a 20 tpi leadscrew where .050 becomes exactly one revolution of the hand wheel. Now make it a 1/2” slot. Hmm...6.49 revs of the handwheel on a 13 tpi leadscrew. Well that’s not so bad. I guess the obvious answer is to mount a dial indicator with a mag base. This shaper doesn’t have a graduated dial on the cross feed. Or if it does, the graduations have faded. Anyhow that’s what made me start thinking about it. But truly there’s no “need”. Actually, since you forced me to do the math, it’s not looking like such a problem anymore. Just looking for group input.

On the subject of the manual: It’s funny how they worded the bit about changing feed direction. Stating how to change feed direction, and following it up with a recommendation to ensure the table is feeding during the correct portion of the stroke. As it happens, anytime you change feed direction, you must also change the orientation of the feed eccentric which dictates when the table moves. So they tell you it’s one easy step to change feed direction. But oh by the way, it’ll be feeding on the cut stroke now, so change this other thing too, if you happen to notice. It probably took me 20 minutes to figure out why it was cutting all wonky when it was headed left, but just fine going right. Ha!
This does seem to be a common idea with manual writers. I guess they didn't want to scare anybody off, but like with the Atlas their terminology isn't really clear but through watching YouTube vids and the Rudy K. vid I put 2+2 together. I inadvertently complicated the whole thing when I methodically took everything apart and cleaned it. The manual was very close to worthless about some of the hidden ways things came apart and makes no mention about proper clocking the timing for the gears that run the rotary for the ratchet. Only through watching vids did I get there was this vast timing difference in how the different Atlas would "click" the advance. You would think they would have put timing marks on everything but I guess they didn't think about maintence. It is a very vague and iffy process to change even the advance amount as there are no graduations on the ratchet wheel. So I just feed everything the one direction that is feeding properly right now. I can really get lost in the minutiae of this old tech.
 

C-Bag

Ned Ludd's bro
H-M Supporter-Premium Member
Joined
Feb 9, 2017
Messages
338
Likes
257
#11
I'm somewhat used to seeing variation in machine tools. But there seems to be some odd knowledge gap in shapers. Or am I just too ignorant to comprehend? Were different shapers for different processes? Like in the case of f350ca's Peerless was it just for roughing in? Or is there something like another finer tooth ratchet that could have been installed? As with the cut direction it's not just a flip of a lever. You had to change the tool, and the position of the link on the ratchet wheel. So there might have been other parts that were supposed to be changed to but are lost to time. Or not.

Did they use DI's on the knee and head to keep track of the cut or did it not matter, because almost universally the dials seem so small as to be worthless. And because the dials were so small the engraving can't be to deep so they went away quick. How did the machinists back in the day keep track or was it all just experience and seat of their pants?

My brother who worked as a machinist makes fun of me for wanting to adjust and clean my hobby machines to take out the play and operate smoothly like I'm going to screw them up. It reminds me of shops where the guy on the line with a little 3 drawer rollaway would make fun of the guys with the big tamale carts. Like they weren't "real men" getting the job done little or nothing and his case doing the job in spec with worn out stuff. Every shop I worked in where there were common machines that everybody used were never maintained. Just used to destruction and put out back. i guess that's why you have to be careful buying an old machine tool used for production.
 

Downwindtracker2

Active User
Active Member
Joined
Sep 5, 2014
Messages
243
Likes
95
#12
I puzzled over how accurate a shaper was, as much to know when I got close on my shop built project. I asked on a forum and the only answer was the skate was important. Since there isn't that much written on how-to for shapers I was able to read some. Again no numbers. A shaper is a tool from the beginning of the last century, so I went back to first principles. The old books talk about picking of the measurement off a rule with dividers by splitting the line. Scribing that line onto the part. That's a +/- .005

The joke was on me, the cheap Chinese 4" milling vise I 'll use on my shaper was made with a shaper. It was within .005.
 

C-Bag

Ned Ludd's bro
H-M Supporter-Premium Member
Joined
Feb 9, 2017
Messages
338
Likes
257
#13
For most of my wage slave career I was a mechanic and was obviously not cut out for it. I was constantly thinking as I'm standing on my head, wishing I was double jointed, tearing the skin off my knuckles, "what WERE they thinking, and what were they on when they thought it?"

I did two stints for two different manufacturers with an engineering dept. and was in positions in both places to interact with the engineers as I was in assembly and it was instructive. Somewhat. Whenever I'd ask why are we doing this, this way? It makes our job so much harder and since time is $$$ it's a waste of $$$. One engineer thought I was being a know it all and wouldn't change. The other outfit I was lucky enough to work with engineers who saw the problem and were happy to refine their designs and we made a great team. In neither place could a get an exact reason for why things were done the way they were. In both places there were too many egos and too many layers of command that was stirring the pot.

So in the case of that lead screw my only guess is they wanted something proprietary that you would have to come back to them if it wore out. But I'm math-impaired and would never try to grok tpi vs feed rate so I get ill never get beyond the seat of your pants machinist.
 

Downwindtracker2

Active User
Active Member
Joined
Sep 5, 2014
Messages
243
Likes
95
#14
One of my favourite saying is "And they thought THIS ? would work ?" I was a millwright so engineers and machinists rarely made it onto my Christmas card list.
 

C-Bag

Ned Ludd's bro
H-M Supporter-Premium Member
Joined
Feb 9, 2017
Messages
338
Likes
257
#15
One of my favourite saying is "And they thought THIS ? would work ?" I was a millwright so engineers and machinists rarely made it onto my Christmas card list.
LOL! That last outfit was a foreign owned co. that bought out an American co. and tried to carry on like it was still an American co. Some of the stuff we'd get from the parent co. you'd unpack and just be floored. It says a lot when you can look at something without running it and know for sure it was junk. We'd try to run it and even though it was undamaged would watch it destroy itself. But anytime you are trying to push conveyor belts or chains you know you're in deep yogurt and we'd see that.

One time they decided they needed a motto and asked for suggestions in the suggestion box. I submitted "We'll defy physics to sell you a machine!" Needless to say I didn't win.

One of the better things they did was have the most experienced assembly guys who put the line together also do the install. I was in on a couple of those and if the original layout was right our install went off without a hitch because it was all done on the shop floor. There was no in the field reengineering because the engineers and the machinist dealt with in the shop.
 

NortonDommi

Active Member
Active Member
Joined
Nov 15, 2016
Messages
265
Likes
166
#16
You are correct about the size and number of teeth on the ratchet wheel. On Imperial machines the thread on the cross feed screw and the rotation of the ratchet are usually able to be set for 1: feed of cut. 2: Spacing for cutting a rack.
Before I got some gear cutters I was about to make a new screw and wheel to cut a Module 1.25 rack as it is impossible with the existing thread unless done manually with a dial gauge and that negates the point of having a shaper as one hand is necessary for tea.
It is there on the 'To-Do' list. It is a simple thing to make and change if needed to do a special task.
 
[6]
[5] [7]
Top