Identify this Fellows?

[Zahnrad Kopf]

Why is the max internal face width 1/2" shorter than the 2" external face width on a Fellows 7A?

Because you have to traverse the saddle outward to cut Internals and this causes the spindle to "pre-load" along some of the rack teeth on the spindle, effectively removing some of the available stroke length. If you traverse the saddle back and forth, you will see the spindle move up or down approximately that 1/2".

 

[Garwood]

Because you have to traverse the saddle outward to cut Internals and this causes the spindle to "pre-load" along some of the rack teeth on the spindle, effectively removing some of the available stroke length. If you traverse the saddle back and forth, you will see the spindle move up or down approximately that 1/2".

Thanks. Looking at it in person it makes perfect sense why the internal stroke is shorter.

This is a strange deal. I looked at the shaper this morning and I have mixed feelings about it. It looks way worse in person than the pictures. It's been in an open air breezeway in front of the guys home shop for a decade or so. Some rust, most of it looks OK, but it's not under power, it's 480 only, his "acre feet" of tooling he claimed to have is a handful of shaper cutters, a beyond fucked straight guide set for a #6, a helical set for a #6, a helical set for a #7 and a couple dozen large non-standard hobs.

He keeps calling the machine a #6, but it's a #7 with 725A stamped right in the face. The accessories he has are mostly for a #6 and don't even fit this machine. Like the extension arm for internal is way too small to fit this machine. He was telling me the coolant pump is missing and I'd need to rig up an electric one, but when I crawled back behind it the coolant pump and belt is all there. Not that it matters much, just kinda painting a picture of a guy who can't remember what any of this stuff is.

Initially, when I met this guy 9 months ago he offered me the (nice) shaper and hundreds of cutters, hobs and several guide sets for $2500. Today the price was $3000 for just the bare (not so nice) shaper.

I was able to test if an example of a part I want to cut internal splines in would fit and I'm now 100% sure a #7 fellows will do all the parts I have in mind which is neat.

The guy's also willing to help me out if I need any assistance. Not sure he's offering much there given he can't remember what machine he's selling or where all the tooling went.

I'm thinking.

 

[Doug]

Just walk away Rene.....
Sounds like Dementia is rearing it's ugly head.
When you come to collect it, it will be $5000, even if you paid for it in full today with a receipt.

BTDT

 

[Mud]

He was telling me the coolant pump is missing and I'd need to rig up an electric one, but when I crawled back behind it the coolant pump and belt is all there.

Remembering I know zilch about 7As - FWIW On my 6As the OIL (not coolant) pump runs in reverse, the belt runs in a figure 8. If the belt is on forward that could be why he thinks it's not there. And they digest a lot of fines, get worn and sometimes need to be primed.
Helical guides sell for high dollars compared to the rest of the machines.

 

[Garwood]

Update:

The guy called me today to admit he was wrong about all the guides and tooling and he'd like to sell it with the bit of stuff he does have for $2500 loaded.

Since looking at this 7A I've reached out to a couple other people I have met with decent Fellows to ask what they'd sell theirs for. Neither was interested in selling even though they don't use them much.

I'm not desperate by any means, but I don't feel like $2500 is an out of line price to pay for the 7A in excellent shape+ atleast one good helical guide+ a dozen or so cutters+ loaded on my trailer+ not that far away.

I proposed to the seller that I come over and take the head apart far enough to establish the condition of the guides. When I was there I took the top hat piece off, it looked like new in the oil reservoir area in there but there's more that has to come off to get to the guides and I didn't go that far. I did remove the cutter mandrel. The mandrel is like new, the spindle OD and ID taper look like new and the work spindle looks like new. The work spindle gearbox has zero slop. The guides have zero slop with a wrench on the drawbar hex. The machine also has a rebuilder tag on the front door that looks like it was put on the last time the machine was painted, the paint looks like it was nice before the machine was stored outside, under a roof for a decade.

I think if the guides in the machine are nice I'm going to pull the trigger on it. I think I should have bought a Fellows first instead of my hobber. The vast majority of parts I want to make with the hobber I have also require internal and shoulder stuff that requires a Fellows.

It seems similar to when I started out into CNC's I bought a big Mazak lathe and that lathe was pretty useless by itself. Once I added a VMC I had a never ending list of stuff to make and things progressed real fast after that. Now it seems like have CNC lathe, gear machines and OD grinder can open the doors for a bunch of products I haven't had the capability for and I should buy the Fellows to bring it all together.

 

[Mud]

A gear shaper is a very handy machine. If you do one off internal slotting you can even use it as a vertical slotter by disconnecting the table feed and using the worm as an indexing device. I haven't done that yet but I have the tools and intend to. You can get special cutters made to make special shapes, I have tools that cut 12 3/8" wide straight sided slots in the ID of a 6.5" ID part which is supposed to be impossible.

 

[Zahnrad Kopf]

A gear shaper is a very handy machine. If you do one off internal slotting you can even use it as a vertical slotter by disconnecting the table feed and using the worm as an indexing device. I haven't done that yet but I have the tools and intend to. You can get special cutters made to make special shapes, I have tools that cut 12 3/8" wide straight sided slots in the ID of a 6.5" ID part which is supposed to be impossible.

Update:

The guy called me today to admit he was wrong about all the guides and tooling and he'd like to sell it with the bit of stuff he does have for $2500 loaded.

Since looking at this 7A I've reached out to a couple other people I have met with decent Fellows to ask what they'd sell theirs for. Neither was interested in selling even though they don't use them much.

I'm not desperate by any means, but I don't feel like $2500 is an out of line price to pay for the 7A in excellent shape+ atleast one good helical guide+ a dozen or so cutters+ loaded on my trailer+ not that far away.

I proposed to the seller that I come over and take the head apart far enough to establish the condition of the guides. When I was there I took the top hat piece off, it looked like new in the oil reservoir area in there but there's more that has to come off to get to the guides and I didn't go that far. I did remove the cutter mandrel. The mandrel is like new, the spindle OD and ID taper look like new and the work spindle looks like new. The work spindle gearbox has zero slop. The guides have zero slop with a wrench on the drawbar hex. The machine also has a rebuilder tag on the front door that looks like it was put on the last time the machine was painted, the paint looks like it was nice before the machine was stored outside, under a roof for a decade.

I think if the guides in the machine are nice I'm going to pull the trigger on it. I think I should have bought a Fellows first instead of my hobber. The vast majority of parts I want to make with the hobber I have also require internal and shoulder stuff that requires a Fellows.

It seems similar to when I started out into CNC's I bought a big Mazak lathe and that lathe was pretty useless by itself. Once I added a VMC I had a never ending list of stuff to make and things progressed real fast after that. Now it seems like have CNC lathe, gear machines and OD grinder can open the doors for a bunch of products I haven't had the capability for and I should buy the Fellows to bring it all together.

The only obvious big deal with that machine is the lack of a riser. The good news is that you can find them. 7's are nice for non gear people because you can train a monkey to run them with little intervention required. So, they are handy. 7's are also still simple enough that there's just not a lot to go wrong. The reason that no one wants to let them leave is that ( in capable hands ) there is a lot of capability in a relatively very small floor space.

 

[Garwood]

The only obvious big deal with that machine is the lack of a riser. The good news is that you can find them. 7's are nice for non gear people because you can train a monkey to run them with little intervention required. So, they are handy. 7's are also still simple enough that there's just not a lot to go wrong. The reason that no one wants to let them leave is that ( in capable hands ) there is a lot of capability in a relatively very small floor space.

I forgot to mention that- It has a 2" riser. More would certainly be appreciated, but I was able to test fit a blank of the primary part size/shape I'd need to make and it seems like enough room to fixture/load/unload.


This "Cut unusual internal shapes" ability of a Fellows actually has me super intrigued. On that subject- Visualize the Fellows change gear trilobe bore. Take away two of the tangential triangular "keys". Would it be possible for a fellows to cut just ONE of those tangential triangular features in a round bore about 3/4" diameter? I have a product in the works that has a feature like that and I was going to mill it 1" deep with a 3/16" high feed endmill. Sounds like a way better job for the Fellows if it can do asymmetrical parts like that.

I guess it would come down to the feed cam and gearing right? If the feedcam plunged in, then backed out for most of a rotation, then plunged back in again, repeat enough times to get the desired size you could do it without taking a monster width of cut maybe?

I'd love to see what the cutter looked like Fellows used to cut the trilobe bores.

 

[Mud]

I'd love to see what the cutter looked like Fellows used to cut the trilobe bores.

I'll bet it has 2 lobes
I have scan of a book that addresses all that. I tried to upload it here but it was too big. I'll try to make it available somehow tomorrow if I can.

 

[Garwood]

I'll bet it has 2 lobes
I have scan of a book that addresses all that. I tried to upload it here but it was too big. I'll try to make it available somehow tomorrow if I can.

If you can't I'd be happy to pay for a copy.

 

[Garwood]

Another question I forgot to ask the gear shaper braintrust-

Does a #7 need an idler gear added to the rotation geartrain when cutting internal? I ran across something talking about this online, but it may have been for a #6? And now I can't find it. The seller claims "He's never needed to reverse the work spindle to cut internal" and that just flat doesn't make sense at all to me. I'd think you'd have to reverse work rotation and it's either done with an external idler or the machine has a reversing box built in somewhere.

 

[Mud]

The inside and outside of these were done on a gear shaper

 

[Mud]

Does the manual posted here explain setup for internal work? https://machinistboard.com/index.php?threads/fellows-gear-shaper-manuals.951/post-16682

 

[Garwood]

Does the manual posted here explain setup for internal work? https://machinistboard.com/index.php?threads/fellows-gear-shaper-manuals.951/post-16682

Thanks!

Page 34 covers it. The work spindle must be reversed for internal work. There's a work spindle reverse built into the model 725A so I should be good to go.

Interesting to read the 725A was purpose made for internal helicals.

 

[Zahnrad Kopf]

I'll bet it has 2 lobes
I have scan of a book that addresses all that. I tried to upload it here but it was too big. I'll try to make it available somehow tomorrow if I can.

It does indeed.

 

[Mud]

It does indeed.

You made one, didn't you?

 

[Mud]

It's 13+ Mb, so I uploaded it to Dropbox. Here's a link, I'd download it and save it to your disk, I don't know how long it will be available there.

Fellows-generating book.pdf

Shared with Dropbox

www.dropbox.com

Here is a cutter I acquired with a machine.





Here's the cutter that makes those straight sided slots. I have to rejigger the machine workpiece retraction when using this, the trailing edge of the cutter drags on the upward stroke becasue of the straight side, I can't eliminate it all I can do is minimize it. You can see the undercut curves on the teeth to generate the straight feature.
I got these made through Ash. I ordered 2, have yet to sharpen the first one.

 

[Mud]

I guess it would come down to the feed cam and gearing right? If the feedcam plunged in, then backed out for most of a rotation, then plunged back in again, repeat enough times to get the desired size you could do it without taking a monster width of cut maybe?

Generally you take a full depth cut, and adjust the chip load by adjusting the rotational feed. The number of strokes to make a full revolution - more strokes per rev = lighter cuts. Sometimes you might make 2 cuts, a roughing and a finishing cut on very large teeth, I never do on the size of parts I make. (up to about 6P)

 

[Garwood]

That's surprising. So for one internal tooth you'd plunge it regardless of the width of cut?

 

[Mud]

That's surprising. So for one internal tooth you'd plunge it regardless of the width of cut?

Right. When cutting a gear you also cut them full depth. Cutting one tooth doesn't change that. If it's a huge tooth that overloads the setup you would feed it in slowly and rotate it slowly to reduce deflection but the process is the same.

The heaviest chipload I find is during infeed because I can't adjust that in the machine, it just goes at full increment plus the rotation feed. Once it's in to full depth the chipload reduces to normal.