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DIY Metal shaper questions

onelittleshop

Plastic
Joined
Apr 19, 2022
I've got a tiny shop and I often build prototypes. Periodically I've wanted a metal shaper. In my potential usage the fact it isn't cutting in one part of the action does not bother me at all. I desire cheap tooling I can grind to shape at 2AM, a predictable action, and a good finish. I've seen people use the carraige on a lathe with a HSS steel tool to shape a gear tooth in brass. I've done some research and found a document done of instrumenting a HSS steel cutter on a big metal shaper in India that broke the cutting ground edge off around 38lbs of force.

I don't need a very large shaper. I don't really want to beat an antique to the end or move a 400lb machine either. A small manual shaper like the smallest Perfecto metal shaper or Rapid Lime metal shaper would even satisfy my needs. After looking for a long time I've had little luck finding these small machines here.

So this has led to a question: given the high gear ratio of a lead screw, what stops someone from operating the ram of a metal shaper with a lead screw instead of a Scotch Yoke? I know they made hydraulic metal shapers, the lead screw would just rid the system of the hydraulics. I mean a lead screw may not be as fast reciprocating as a Scotch Yoke but surely a lead screw on dove tails can apply more than 50lbs of force pushing a piece of HSS steel as a tool. Sure you might not get to common SFPM rates if you go slower, but I guess that's not going to ruin the tool as long as it can keep cutting and the clapper works.

I'm thinking if someone just used some CNC steppers and appropriate parts there seems no good reason one can't achieve the table advance in sync with the ram either.

Am I missing something? With the average shaper in my area hitting $1,200 and a pile of stepper CNC stuff laying around this alternative seems economically attractive to me.
 

Paolo_MD

Stainless
Joined
Apr 6, 2013
Location
Damascus, MD
I believe that you need a minimal cutting speed in order to achieve a certain finish and not to prematurely destroy the tool.
On Youtube you can find several close-up high-speed video of lathe tooling cutting at various speeds: there is a lot going on and, at optimal speed, the very cutting edge of the tool doesn't even contact the piece. It's practically the chip pushed by the chip breaker that continues the cut.

I am pretty sure that the same goes on with the shaper tool.

Paolo
 

onelittleshop

Plastic
Joined
Apr 19, 2022
I thought this about tool wear as well, but a manual shaper isn't by necessity going to maintain a given SFPM. It's just a lever I estimate about 3-4 feet long on a pivot with a fulcrum. Perhaps there is an optimal speed to get the most tool life from the tooling, but even if I buy one of these manual machines, I'm not sure I would operate at that speed anyway as the human pulling the lever over and over at 2AM.
 

onelittleshop

Plastic
Joined
Apr 19, 2022
I'd happily drop $1200 on a shaper, but sure, why not, servo driven cnc digital readouts on a shaper, make sure to post pics:D

Edit: Bonus points for adding a servo driven rotary table!

The issue is that at $1,200 used what you get has every bit of wear and tear it earned from decades of use. So you then have to think about repairs on something where spare parts might not be available. I get a lot of use from old lathes and milling machines, I have to consider how much use of this shaper I would get in doing a similar restoration especially will all my jobs being short runs.

At least if I build it from left over parts, it would be worthy of entertainment and a prototype like all my other works.
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
The Sellers flatbed planer of around 1910 used a leadscrew and nut to drive the planer table.....three start thread on about a 6" dia screw.............However ,if hydraulics had been sufficiemntly advanced at the time,they would have used direct hydraulic drive......and so should you.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
I can visualize it, make it from modular pieces, machined pieces will be easily made on a Bridgeport mill.

Modular so you can re-configure it as needed, slotter, shaper, punch shaper etc.

Do not skimp on the steel, use 1/2" to 1" plate, standard a.c. buzzbox can weld it all together.
Base should be about 350-500 lbs.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
The issue is that at $1,200 used what you get has every bit of wear and tear it earned from decades of use. So you then have to think about repairs on something where spare parts might not be available. I get a lot of use from old lathes and milling machines, I have to consider how much use of this shaper I would get in doing a similar restoration especially will all my jobs being short runs.

At least if I build it from left over parts, it would be worthy of entertainment and a prototype like all my other works.

Gee Mr Wizard, thanks for that info, I've bought all my machines brand new, and only drive them on Sundays, did not know they get wear, who knew....
 

onelittleshop

Plastic
Joined
Apr 19, 2022
Gee Mr Wizard, thanks for that info, I've bought all my machines brand new, and only drive them on Sundays, did not know they get wear, who knew....

The reason I stated the obvious is because I am a new forum member and I'm betting in a few years / decades someone will hit this on Google and I wanted it to be clear my motivations at this time.

That said, thanks for your contributions. I'm reading this with a smile as I hope it's meant in good nature not that I offended you.
 

neanderthal mach

Hot Rolled
Joined
Dec 18, 2008
Location
princeton b.c.
You want a hand shaper, how hard have you looked?
Strong Arm Shaper – martinmodel.

Whatever source you found that mentioned cutting edge failure at only 38 lbs of force should be ignored as complete BS. What does that even mean? 38 lbs applied over how much surface area? Whatever numbers they were making up, I've seen reliable and trusted data pointing out it takes a minimum of 150 lbs of down feed pressure on a HSS drill point just to drive a dead sharp 1/2" drill through mild steel. That's the axial load, the radial torque numbers would obviously be much much higher. Given the handle length and feed pressure I've applied on any drill press or mill I've run, that number seems if anything a bit on the conservative side. I've also broken hundreds of 10 - 50+ ton rocks with much less capable high carbon tool steel points and a 5,000 psi hydraulic hammer driving them. If that 38 lb number per ?????? came from running test results on a shaper in India, then it all sounds just about as informative and trustworthy as there India based scam call centers are.
 

onelittleshop

Plastic
Joined
Apr 19, 2022
You want a hand shaper, how hard have you looked?
Strong Arm Shaper – martinmodel.

Whatever source you found that mentioned cutting edge failure at only 38 lbs of force should be ignored as complete BS. What does that even mean? 38 lbs applied over how much surface area? Whatever numbers they were making up, I've seen reliable and trusted data pointing out it takes a minimum of 150 lbs of down feed pressure on a HSS drill point just to drive a dead sharp 1/2" drill through mild steel. That's the axial load, the radial torque numbers would obviously be much much higher. Given the handle length and feed pressure I've applied on any drill press or mill I've run, that number seems if anything a bit on the conservative side. I've also broken hundreds of 10 - 50+ ton rocks with much less capable high carbon tool steel points and a 5,000 psi hydraulic hammer driving them. If that 38 lb number per ?????? came from running test results on a shaper in India, then it all sounds just about as informative and trustworthy as there India based scam call centers are.

The links I have from India:

Experimental setup for shaper tool with dynamometer | Download Scientific Diagram

http://www.ijfrcsce.org/download/conferences/ICATET_2018/ICATET_2018_Track/1517648182_03-02-2018.pdf

I do know about Martin Model. I've contacted them about their gear hobber castings in the past. I cut gears on my lathes today with a CNC unit I designed. It seems to me that if I have to finish those shaper castings I'm not that far from designing my own machine.
 

onelittleshop

Plastic
Joined
Apr 19, 2022
After enough feedback and thought I'm pretty convinced the 38lbs is probably bad data in those papers I linked or just oddly presented.

I have some odds and ends in the shop and the most thrust I can get from a large stepper driven ball screw linear actuator I have is about 200+lbs.

As recommended I am reconsidering using smaller hydraulics because there will come a point of economy where the pump and double acting hydraulic cylinder are cheaper than linear actuator with a suitable set of bearings, or a much longer linear actuator driving a lever instead of the shaper ram itself. Even using the lever with a linear actuator will likely limit the ram travel in a way the hydraulics would not as the short part of the pivot is single digit inches and the long part of the lever is pretty long in feet.

My needs here are pretty meager as far as material removed per ram stroke of the shaper, but it might be nice to have 8-10 inches of travel instead of say 5 inches.

So I'm going to put some thought into a hydraulics combination on the lower end of the pressure spectrum at some reasonable cost as I don't use many hydraulics and have limited odds and ends floating around my shop.

Again thank you to all contributors.
 

PeteM

Diamond
Joined
Jan 15, 2002
Location
West Coast, USA
The VersaMil kit (look it up) included a tiny short-throw shaper attachment, ideal for things like spur gears and keyways. The basic "Mil" attaches to the compound of a reasonably stout lathe, so it might be an option if one little shop doesn't have much space.
 








 
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