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ot----secrets of Moore jig borer B-18

JHOLLAND1

Titanium
Joined
Oct 8, 2005
Location
western washington state
one of the final manual jig borers produced by Moore Special Tools

so to day I begin tear down and retrofit

this machine build year 1978
wired 440 vac--no option of rewire to 220 vac---so motor must go
this machine had option of power feed X and Y axes also rotary encoder
positioning x,y

many pics of Moore jig borers are retrievable on web but I did not find tear down pics

of most interest is spindle drive

consists of 2 hp heavy 440 vac motor with 2 speed option 860 or 1725 rpm

secret of Moore speed setting from 60 to 2250 rpm is stacked reeves drives

these are smoothest, most solid construction I have encountered

but---I will modify drive unit by replacing oem motor with 220 vac 2 or 3 hp
1750rpm and vfd

you will notice final output of speed assembly is thru 2 v-belts
this construction will remain--all vari-sheaves will be removed
 

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Why not use the original motor and use a transformer to make 440V?

I agree, and even if you must replace the motor with a VFD setup, why so low horsepower? If you want good performance at lower speeds, I'd think you should use at least a 5Hp. And check if there'll be any "cogging" effects with the new drive, it would be a shame to compromise bore finish quality on a Moore.
 
my machine retrofits are characterized by 220 volt single phase mains input--even if it requires up to 20 hp vfd dedicated to one machine--sadly, the 2 hp Robbins and Myers spindle motor was dual voltage 220/440 when it left the factory---but was likely rewound to 440 only

the Moore system of power transmission to the spindle relies upon very substantial rotating inertial mass to smoothly swing boring bars up to 5 in diameter

mass of all spinning components allows elimination of gearbox for low tool rpm application while preserving superb surface finish--and I likely will forfeit a degree of performance in this category---
my focus is increasing rpm from factory 2250 to equivalent of bridgeport 2j head---4200 rpm
the proprietary Moore spindle socket taper will undergo transformation to either 30 Erickson or 200 Kwik Switch--gun drilling of the very long Moore spindle may be required
the key observation here is production of a machine incorporating clockwise and anti-clockwise rotation--it is my impression Wayne Moore was almost apologetic with regard to clockwise function only of the company tooling system

Moore jig borer tools were not intended for milling applications---when this machine conversion is complete I anticipate a more versatile unit with an expanded envelope of performance which I hope justifies the compromises

stay tuned :)
 

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Todd

power feed on unit has variable speed as control voltage to servo drives is varied---0 to +10 vdc

servo drives do not have encoder input and cannot be controlled for digital positioning
the user pushes a button and varies speed while the axis moves
fine positioning performed by manual handwheel

when I finish retrofit I plan on trial of power feed milling--
 
Just curious is this machine retrofit for yourself or a customer or for sale after it is complete?
It seems such a shame to trash all that fine work for a bit of a bump in speed?
What will be the intended type of work?
 
Just curious is this machine retrofit for yourself or a customer or for sale after it is complete?
It seems such a shame to trash all that fine work for a bit of a bump in speed?
What will be the intended type of work?

I am collector/retrofitter
in order to fully understand a mechanical mechanism you must tear down and reassemble or execute working modification--upgrade

there is no current market for Moore jig borers as configured by factory

otoh, there is a market for retrofitters updating Moore jig grinders

the jig borer was advertised as a holemaker---with great limitations
so, I referenced slow spindle and painfully antiquated tooling--no spindle reverse
the primary reason the Moore jig boring product line lasted as long as it did was fabulous positioning accuracy producing one offs

used machinery buyers are more complaining than ever--and none want spindles that spin less than 4K

when I complete this conversion as a two axis cnc--I will play with it a while then send it to a good home:)
 
Thanks for a very good reply.
So when it is done it will be a light duty mill or still just accurate boring?

It does seem to me that if you doubled the motor rpm you would achieve the speed range you are after, 120 to 4500 rpm? Provided you could find a two speed motor 1725/3450.

They are such fine machines that it is almost required that they be upgraded to last many more years.

If I am down your way it would be great to see your shop. It think I bought some items from you a few years back.

Keep us posted on your progress.
 
new power

all components of vari-drive assembly were removed

3 hp donor motor --aluminum frame 1700 rpm dual voltage C-frame
is employed as new power---but flange dimensions do not allow direct bolt up to factory --so flange was notched

---oem motor is split and output end housing bored and cut off creating clamping ring allowing direct clamping force around full circumference of
donor motor flange

v-belt aluminum sheave was turned down and factory sheave spindle ground on od grinder to 30 mm diameter--this was required dimension of support bearings id bore--assembly was pressed and installed on bare vari-drive frame

remaining work is selection of coupling assembly mating 30 mm v-belt drive input shaft to 1-1/8 inch output shaft of 3 hp motor--then unit will be rotated 180 deg and installed--

pics are of inverted drive assembly
 

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power run

vfd power applied to new motor drive

this configuration does not like spindle frequency beyond 2500 rpm---motor is 1700 speced at 60 hz

moore belts are stretched asymmetrically --will need replacement

the jig borer belt tension is set with cast aluminum hood on since the adjustment screw is built into the hood --

belt whip even with new v-belts will likely eliminate goal of 4K spindle speed--this would also require 3600 rpm drive motor capability

short clips


YouTube

YouTube

YouTube
 

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Wouldn't a wide cogged belt belt and pulley combo solve the issue?


25 years ago we did what you suggest to a bridgeport 2j head --removed vari-sheave configuration and replaced with goodyear cog belt drive with vfd---worked beautifully--but the bp head allowed a small circumference belt with low mass

belts on the B-18 Moore are 92 inch==7.6 feet and there is no easily modifiable architecture allowing distance closure between motor and spindle sheaves

so--i was looking at my Romi lathe 20x40 with 3500 rpm spindle --- 3 v-belt drive---to reduce belt issues Romi uses low mass v-belts of max width 3/8 inch---Moore belts are about 1 inch across

v-belts provide a margin of safety in the event of tool seizure--they slip

analyzing the architecture of this machine reinforces Moore commitment to provide top end spindle speed at 2250 rpm---this is actually a drop from the No 2 jig borer of 20 years earlier with 2500 rpm spindle

max rpm of G-18 jig grinder is orbital spindle speed of 300 rpm---grinding wheel of course---80K +

I could push spindle speed higher by modifying sheaves to 3/8 inch and going to low mass polymer---this is the approach Aciera used on the cnc No 5--fly weight belts run at high rpm---but the Moore is what it is--so I now move on to conversion of spindle taper to 30 erickson or 200 kwik switch

a sobering undertaking :!
 
25 years ago we did what you suggest to a bridgeport 2j head --removed vari-sheave configuration and replaced with goodyear cog belt drive with vfd---worked beautifully--but the bp head allowed a small circumference belt with low mass

belts on the B-18 Moore are 92 inch==7.6 feet and there is no easily modifiable architecture allowing distance closure between motor and spindle sheaves.

Your goals need a redefinition of easy.
Ditch the motor and drive casting all together, Fabricate a mount to hold the drive motor inverted in the place where the vari-speed pulleys were. This should cut 18-24" off the total belt length.
 
Your goals need a redefinition of easy.
Ditch the motor and drive casting all together, Fabricate a mount to hold the drive motor inverted in the place where the vari-speed pulleys were. This should cut 18-24" off the total belt length.

if this Moore was one unit of a production shop with part quotas--your suggestion would be a likely option---but alteration of the machine profile envelope would compromise its character--

and the core of my undertaking will be spindle conversion to some quick change format allowing bi-directional rotation

x-y cnc capability also planned

and even after all of the tweaking---I may not recover cost of tool and
added components---but this process is meant to be an adventure :)
 
its alive

using vfd set to 60 cycles jig borer spins at factory spec of 2250 rpm

analog tac display is neat feature and requires no input power in any form--magnetic induction moves hand
with this indicator Moore pays homage to the greatest legacy watchmaker--
I will defer naming this luminary to an astute reader;)


video

YouTube

YouTube
YouTube
 

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the barn find

both x,y encoder scales work

drive system for y axis functions as expected

x axis drive has malfunction characterized by runaway

step motors will replace brush dc servo motors on this unit--little liklihood of runaway events

---the barn find--removed fabric way covers and found 1795 silver dollar--
a fake from asian vampire hub counterfeit ring---but a momentary high :)


YouTube
 

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thumbs up---open frame motors

so I initially mated 3 hp 1700 rpm motor--off italian woodworking machine operating at fixed speed and light cutting load --to the B-18

I could push it with inverter to 50 cycles and then vfd faulted--until
total ground fault short

pulled unit and found smoked windings--this was sealed explosion proof motor operating in cabinet shop--interior coated with fine hardwood dust--which did not ignite but coked--taking insulating polymer coating with it

had 2 hp chinese bp type mill motor and fashioned it to fit---works great --open frame with fan --40 minute test run--motor did not heat above 95 F

it is clear that hardware of this machine will not allow spindle speed past 2400 rpm--
 

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