Question For Shaper Experts

I've had a little 7" AMMCO shaper for a few years. I've used it for flat work and slotting many times and it's always worked fine. Last week I needed to make a couple tool holders for small internal keyways. I welded a piece of 1" round stock to 3/8" x 1" flat stock. I then squared everything up and bored a hole through the round stock for a 1/2" boring bar.

Everything seemed true and square, but I thought I should set it up with a bar in the shaper just to make sure. I clamped the tool in the tool holder, extended the bar to the maximum length (12") and tightened it in the tool holder. The I setup a dial indicator on the table and hand cycled the ram. Much to my surprise the bar was moving almost .010 side to side as the ram went through the 7" stroke.

I narrowed the problem down to play in the clapper box. The clapper itself will move .005 side to side on the pivot pin. Not being a shaper expert I'm wondering if some play in the pin is normal, and if so what would be the maximum amount allowable before a repair is needed. I'm considering whether it's time to disassemble the box and insert a new pin or possibly bore it and the clapper for an oversized pin.

Well I am no shaper expert but I have a 12" Vernon and am learning. I have read that you want the clapper pivot as tight as possible without binding. That's why they are on a tapered pin. You ream it with a taper pin reamer just enough to clean it up then take just a little more out of the clapper until it will just move. I would assume you get a new pin each time.

wdTom said:

Well I am no shaper expert but I have a 12" Vernon and am learning. I have read that you want the clapper pivot as tight as possible without binding. That's why they are on a tapered pin. You ream it with a taper pin reamer just enough to clean it up then take just a little more out of the clapper until it will just move. I would assume you get a new pin each time.

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A 12" Sheldon (Vernon) under-roof here as well. Not my first shaper rodeo.

Pin fit IS important, but the clapper also has to SEAT repeatably and true as it takes up pressure when the tool encounters the work.

Pin fit can remain an important player under load, but is not the only one.

Bill

Side to side at least as important. I had to make this since the 36" Ohio came with NONE. The fit side to side (box to clapper block) was less than .001 when I put it in service

I've seen clappers that had their rear corners knocked off to 45 degrees, with a corresponding fit inside the clapper box. Always assumed the manufacturer was hoping to make the clapper center in the box, without having to rely on the flat sides of the clapper. Only seen it on a couple machines, so it must not have worked, or perhaps was just deemed an unnecessary manufacturing expense.

Andy

Andy FitzGibbon said:

I've seen clappers that had their rear corners knocked off to 45 degrees, with a corresponding fit inside the clapper box. Always assumed the manufacturer was hoping to make the clapper center in the box, without having to rely on the flat sides of the clapper. Only seen it on a couple machines, so it must not have worked, or perhaps was just deemed an unnecessary manufacturing expense.

Andy

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May have worked a treat when tested, new. Then made for a right challenging maintenance issue in the field.

.007" is huge and multiplies at bar extension due to added deflection (bending) as you have discovered

You could probably work around it by using undersize tools and working to each side. However, the taper of deflection could still be a few .001's combining both sides. centered tools with very minimal or none side clearance might track straight enough. My 3/16" keyway cutter has slightly pos rake but no side rake & works fine for the typical depth of a 3/16" keyway. I have used 1/4" in a mill to slot out work, similarly - just end rake but none on the sides.

If you start to use the shaper got the diversity of tasks for which they can be so practical, versatile and even, yes, fast; a sloppy clapper will become an increasing nuisance. But there is very little fixing for one other than scraping out the housing on both sides perfectly parallel, or maybe faintly tapered, and making and scrape fitting a new swinging block out of good CI.

You are correct that even if you ream the bore, the old pin will not likely be useable. They wear oval shape, and the clapper can eventually rise and fall on the pin, as well as wag side-to-side.

I decided with that much effort, to put a hardened taper gib in the one I rebuilt for my planer.
I made the new pin out of S7 and hardened it. I made the reamer for the hole out of an old bridge reamer core. Set it up on the T & C and reground the taper and lands to something that "looked about right" for taper and made the pin to fit. (I probably calculated a taper based on the material size in the donor reamer, and an estimate of the old taper, but I forget what I decided. )

FWIW ..you will be better served turning up a straight thru boring bar for internal work ...just remove the lantern tool post & turn a bar w/ flange on the end to fit the rear of the clapper & threaded for a nut to go in front of the clapper & lock the bar .....this removes the cantilever effect & is way more ridged , particularly on small shapers
nothing new here ... a 1/2 in & 5/8 in bar arrived w/ my 1903 Steptoe shaper several years ago & from the beat up appearances seem to be dated from same era..also recommended by Canadian shapermeister ,Doug King when he visited me here abt 13 yrs ago
best wishes
doc

Plus, if extended like that, if I understand what you are doing, I'd tighten the setscrews to immobilize the clapper. But maybe I missed something.

Some of the shapers I've owned came with setscrews to clamp the clapper, some didn't, but all leave with them, as a long inside key is real hard to cut without them.

Thanks everyone for your input. I did disassemble the clapper box yesterday for inspection. I can't see any wear on the clapper block or the box itself. There is a film of old cutting oil or whatever between the box and the block, but no evidence that either are or ever have been wearing against each other.

I did however notice the tapered pin does not have the standard dimensions of a normal 2" long #5 pin. It's about .005" over in that the large end measured .294' as opposed to the standard of .289". The small end is also oversize by about the same amount in that it measures .252 rather than .247. It's a fairly soft steel and both ends do show some marks like it's been tapped farther in the hole and removed more than once. I suppose it could be slightly deformed from installation and removal. I haven't measured the bore of the block yet to determine if the pin is oversize.

On Edit: I'm wondering if it's possible that somewhere along the way someone used a longer (4 1/2" or longer) #6 dowel pin and cut off both ends. Since the taper is constant at 1/4" per foot I suppose it's possible

I did reassemble everything and when the large end of the pin was flush with the clapper box the side play was down to less than .002. I wasn't thinking and didn't measure the pin diameter along the length to determine if it was worn.

As for extending the boring bar out 12" I have no intention of using it at that length. I just did it to see how much (if any) deflection there was. It will in all probability be extended about 3" from the clapper block. I am also in the process of making a couple other straight through tool holders as time allows. This is the style that was originally offered as an accessory for the machine.

There are 2 mentioned in the owners manual:
http://www.lathe.com/catalogs/DeltaMilw7ShaperInstrGS.pdf

One is 7/16 diameter (part #27-900) the other is 5/8 diameter (part# 27-901. There is a graphic of each on page 15.

Wow, then the two that came with my old Ammco shaper were probably original. They had a short knurled area at the end and the transverse square broached hole close to that knurled area.

BTW, I'm sending 33 blanks to a gear house to have the helical teeth cut today, for Ammco shapers. I'll probably sell them on ebay again. Phenolic bull gears identical to the originals.