Shaper ram gib adjustment

Whilst slotting a 3/8" square hole with my shaper I discovered that the ram gib was in need of adjustment, measurement with two dial gauges and with the ram fully engaged in the dovetails was .005" front & .001" rear side to side

I adjusted the ram gib to give .001" side to side clearance front & rear, at which the resistance when hand cranking the ram felt much the same as before adjustment. I then thought to check through various shaper manuals & found that none gave a specified clearance.

I am curious to know if others have a manufacturers specified clearance or have arrived at something satisfactory through experience.

regards

Brian

If you've got .001" clearance all over, that is very good for an oil film. Typically, I'd expect some sort of unequal tapering wear that would prevent getting a used machine that tight in full travel of the ram in full ahead and full back positions.

Setting the gib clearance in a used machine tool may not be a one step adjustment. The amount of wear on the slide is the final determinant in setting the gib. If the wear is significant it might be possible to set the jib to almot zero clearance at the ends of the slide travel but be loose and sloppy in the middle. The typical wear pattern for machine slide is hour glass where the center wears more than the ends. There is no fix for this but reconditoning the slide but it may be possible to find a compromise setting that will allow you to run the machine until you can fix it.

Shapers pose a particular problem when the ram slide is worn because the ram runs under power. In a hand operated slide you feel the drag as the clearance transitions into interferance. A shaper may power the ram into interferance tight enough to jam the slide into immovability.

Setting gib clearance by feeler is good if the slide is in like new condton and there in no oil present to confuse the setting. A feeler not as reliable as using the gib. The gib has a 1/4 per ft taper (metric world: 1 in 50)but 1 in 50 is close enough. 0.001" clearance equals 0.040 movement on the gib.

Here's what your do. Hand position the ram on the ceenter of the stroke. Using the adjutment nuts seat the gib firmly to sguash out all the oil. Pull the gib back to unseat it, back the nuts clear in both directions, and firmly seat the gib with fingers alone.

At this point there should be zero clearance. Check the ends of the gib with feelers. A 0.001 feeler should be rejected if the machine is in like new condition. There may be some taper or hour glass in the ram. If there is hour glass the feeler will pick it up. You do NOT want to set the ram clearance so small in the center of the stroke that it will jam at the ends of the stroke. Make note of your findings.

I'll finish this later

Hu

I too was somewhat surprised, but the machine when I acquired it had clearly seen very little use, perhaps even more surprising was that lubrication had been well maintained.

Forrest

You may not have noticed but the gib is a heavy "side piece" rather than a captured taper gib (see picture) I did try extending the ram fully forward & checking the side to side dial gauge readings whilst pushing on the front of the ram, having "seated" the middle adjustment screws the gauge reading was .001"
I take your point entirely that with a tapered gib on a shaper ram too little clearance could result in mechanical mayhem.
Please do continue as I have yet to be other than enriched by your comment.

regards

Brian