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shaper cross feed

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bricky12/01/2022 15:37:07
571 forum posts
68 photos

I have the plans for the unfinished shaper I inherited but I can,t understand how the cross rail feed is stopped ,also do I have to have a left hand cross feed lead screw.Any help from small shaper users will be appreciated.

Frank

John Hinkley12/01/2022 16:38:04
avatar
1301 forum posts
423 photos

Without greater detail of the shaper design, it's difficult to give meaningful advice, but I would venture to suggest, if it's a home brew, there's no reson that I can think of that would preclude the use of a right hand thread for the cross feed. It will just mean that the actuater operates in the opposite sense. My Perfecto has a simple ratchet mechanism to move the ram. If it would help, I can try to take some close-up photos and a brief explanation if you PM your email address.

John

Added: Ian Bradley's book, "The shaper machine" will provide some useful reading, if you are new to shapers.  I have a pdf copy, should you require it.  And there is a web site that specialises in the Perfecto Here

Edited By John Hinkley on 12/01/2022 16:42:08

Clive Foster12/01/2022 16:40:30
3103 forum posts
107 photos

Normal practice with power feed shapers is to have a plain section of just under thread root diameter a little longer than the feed nut at each end of the feed screw. So the nut runs off the screw before being driven into the casting as a hard, damaging inducing halt.

Feed is commonly by a simple ratchet system driven off the ram drive mechanism. One or more clickc of the ratchet during the return stroke. Only separate control of feed is by disengaging the ratchet plunger from the ratchet wheel. So generally the feed is going all the time the ram is moving.

Given the slow speed at which shapers run its not too hard to pull the ratchet plunger when the machine is running if you so desire. Normal practice is to simply stop the machine at the end of each pass with the clutch, if it has one, or by stopping the motor.

Some of the big boys are seriosuly more sophisticated. Especially the monster hydraulic Cincinnati and Rockwell beasts.

Clive

Edited By Clive Foster on 12/01/2022 16:41:43

Joseph Noci 112/01/2022 17:42:51
1069 forum posts
1307 photos

And the not so big boys too...

side-1.jpg

John Olsen12/01/2022 19:53:56
1240 forum posts
94 photos
1 articles

The usual feed system uses a ratchet wheel that has square teeth. The spring loaded pawl that engages with it has an angle on the end, and can be rotated so that the ratchet drives in either one direction or the other. There is a slot in the tube that engages with a pin through the pawl. So in normal use, when the cutter has passed the end of the job, you pull the pawl back against the spring, turn it through 180 degrees and drop it back into the slot again. Usually you then need to rotate the manual handle to take up the backlash so that it starts driving again to pass back over the job in the opposite direction. At some point while the cutter is past the job, you can wind on a bit more cut. Unless the shaper is running very fast, you can generally do this without stopping the machine.

When you don't want the feed to drive, you pull the pawl back out of the slot and turn it through 90 degrees, this stops the pawl engaging with the ratchet wheel.

Some machines have provision to change the stroke of the feed system, so that the pawl picks up one, two, or even three teeth on the ratchet, giving a coarser feed.

John

RobCox12/01/2022 20:45:47
59 forum posts
20 photos

Don't forget that the pawl should drive the feed on the return stroke of the ram and click during the cut

bricky13/01/2022 12:50:08
571 forum posts
68 photos

Thanks for your informed replies.Clive has answered what I required and is obvious once described.The shaper was 80% finished when I aqired it and the plans have written on them is practicalmachinist.com pootatuck metal shaper 1930.Made out of plate and well wellded.I think he couldn't make the drive gear to the skotch crank and pinion drive.As he has made the crank mechanism well and I can't get the machine under the mill to alter it as the plan,I have fitted a 100tooth gear on the crank shaft and fabricated a cage to carry a pinion and pullys bolted on with slotted adjustment to the bolts for depthing the gears.The motor and drive pullys will be hinged off the back of the shaper.The ramm was fishbellied and I could just get it on the mill to flatten it this made swivelling tool carrier out of square and the bore also.When the ram was having the top of the slide true I cut across the face of the ram to allow trueing on the lathe faceplate and allow me to true the bore.Now to the bearing slide which is alsobowed from welding I can't get it under the mill or to support it with the head horizontal,so a lot of scraping to come.Something I haven't seen before is he had inserted a strip of brass to both sides of the of the bearing with gib screws from below.

Frank

bernard towers13/01/2022 14:01:03
568 forum posts
109 photos

Rob can you explain your reasoning behind this because if using a round nosed tool in both directions it means you have to change the auto feed adjuster to the opposite side of the actuating shaft every time you change direction. On the other hand if it was opposite to our thinking the backstroke would not be dragging on uncut material. Just a thought!

RobCox13/01/2022 15:46:00
59 forum posts
20 photos

Advancing the feed on the backstroke is the way all of the advice I have read and watched has advised it. It puts less strain on the feed mechanism, especially if you're advancing more than one click on the ratchet.

Additionally, I tilt the clapperbox to ensure that when the tool lifts on the return stroke it moves in an arc such that the tool tip moves away from the cut face. Angle it the wrong way and the tool is forced into the cut edge. You'll know if you've got it wrong as it doesn't sound right and both the tool and the finish suffers.

The backstroke will always drag over uncut material. Whichever stroke the feed is increased on will result in a diagonal trajectory on the workpiece, without feed the trajectory over the work is in line with the ram.

Clive Foster13/01/2022 16:53:27
3103 forum posts
107 photos

On my Elliott 10M the feed ratchet increments during the stroke direction change. So going one way it feeds over the end of the cutting stroke and the the other over the beginning. At any sensible feed rate you loose very little of the ram stroke to feed. Perhaps 1/2".

Clive

bernard towers13/01/2022 18:42:51
568 forum posts
109 photos

I must admit that my clapperbox is vertical unless being used in the vertical mode as recommended in Shaper Operations.

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