The principle involved is the cutter is formed to cut a rack, i.e. ground as an acme threading bit, with the appropriate angles for the gear. The blank is on a spindle which has one end turned to the pitch diameter minus half the tension diameter of the wire which is anchored on one end, wraps once around the spindle, and then is anchored at the other end with a tension screw. As the table traverses, the spindle and blank are turned by the wire timed by the pitch diameter with wire factored in
I'm currently making a pattern for a couple of angle plates for my shaper to do the same thing, only on a bigger scale as I have a Stanko 20 " shaper. I'll be looking forward to more videos on the subject. Good luck with yours. Best Wishes.
Correct me if I'm wrong, but this is showing a gear generating process where the tool is a rack tooth profile (as in straight sides) and the table is passed across under the tool as the gear blank is being rotated at the same time by linking it to the table cross feed drive. This will generate one tooth with correct curved sides. The table is then brought back to the start position, the gear is indexed one tooth division, and then the process is repeated. I'd like to do this on my shaper.
I'd like to see the gear train and dividing setup to do this as it is fairly complex. The beauty of it all is one rack profile tool will cut any number of teeth gear to the correct profile. With the right setup, it should also be able to cut bevel gears as well.
Please Rattycorner, show us another video of the gear train and dividing setup used to do this. It has become a lost art. Also the mathematics required to calculate the gearing ratios needed to get the roll of the gear correct. Well done
I've been occupied on lots of other things since I posted that video. I had made another video to try to explain it better when I cut the pinion that it was designed for, but screwed up the uploading to youtube, then deleted the file before I realised that the clip hadn't appeared...
That pinion, by the way was a 14 tooth 20 degree PA, stub form, 22DP pinion for the carriage of a Hardinge HLV lathe that I'm refurbishing. It worked out perfectly.
I'll get the original jig off the shelf and set up the camera on a tripod so that I can show the component parts and explain the workings and maybe show a better picture of what's actually happening, then try to edit the clips together to make a more useful video.
No gear train is required, the usual way to do this on a shaper is to machine a pulley a cable thickness less than the required average contact diameter and wind a single turn of cable around the pulley, anchored to the pulley in one place and anchored to a stationary point at each end. Normal table crossfeed gives the correct rotation with this method Steel tape appears to be used rather than cable here. Look up info on gear cutting to find out the correct contact diameter.
too me it looks like the table moves to the right, the tool moves down and the gear itself turns.
If the tool is shaped like a gear why not just feed the tool down until final depth then bring it back up rotate the gear and start over on a new tooth.
think of it this way, you don't shove an entire hamburger in your mouth at once when you eat one right? you take it one bite at a time until you are done and then go get another burger and repeat the process. You do the same thing when machining something, bite after bite until you get what you need.
well of course but both ways i describe take small passes. I just wanted to know what was acually happening in this video since its shaky and blurred its har to see.
If the tool has the shape of the final gear it doesnt make any sence to move the table and the gear while machining one tooth. That may not be the case either maybe it just looks that way? Maybe it is like fowlera7 says but to me it looks like more is going on.
if the table moved side to side the gear would be junk.the table moves up to the tool and the gear is rotated by the jig used to hold it.this is the longest way to cut a gear even in bress.
Care to explaine what we are seeing? I can see the crossfeed screw is turning, is the work advanced left/right? is the gear turning? is the tool feeding down?
It looks like an involute gear is being generated, not cut. The cutting tool is a single tooth rack profile with clearance not an involute. You do see the table move across and the pinion turn. As the table moves across, the pinion is turned by a pulley behind to simulate the meshing of the gear with a rack. because there is only a single rack tooth the gear needs to be indexed,
Could you do a video explaining the setting up for generating a gear? I would like to do this sort of thing but it is difficult to find anyone who knows how. There would be some interesting calculations to get the dividing head to turn at the right amount as the tool passes over. Have you cut bevel gears like this as well?
Shapers are very versatile machines that can accomplish an amazing range of work . Most of us only use 'em for quick roughing, or some simple plane surfaces. Nice to see 'em doin something more challenging.
I ground the tool bit with a surface grinder. The bit is a 14.5° ACME type cutter with 2.5° of relief. I got the dimensions from Machineries handbook. The involute form comes from indexing the vertical cutter across the blank as the blank is rotated.
The principle involved is the cutter is formed to cut a rack, i.e. ground as an acme threading bit, with the appropriate angles for the gear. The blank is on a spindle which has one end turned to the pitch diameter minus half the tension diameter of the wire which is anchored on one end, wraps once around the spindle, and then is anchored at the other end with a tension screw. As the table traverses, the spindle and blank are turned by the wire timed by the pitch diameter with wire factored in
Mrdiehard57 1 month ago
for those looking for more detail its basically this jig
neme-s.org/Shaper%20Books/Michael_Moore/shaper%20gear%20cut.pdf
yugamibritten 3 months ago
Sorry folks, he's still not done the second one. One day maybe...
rattycorner 2 years ago
Looks like someone can use this same process for cutting splines...shaping custom inot shafts. Is that right???
SteelKahuna 2 years ago
Well the months up!
I like the little angle plate to carry the pinion.
I have a Elliot 10" shaper and am in the middle of tooling up.
Cheers
shedfullnow2007 2 years ago
I'm currently making a pattern for a couple of angle plates for my shaper to do the same thing, only on a bigger scale as I have a Stanko 20 " shaper. I'll be looking forward to more videos on the subject. Good luck with yours. Best Wishes.
flyingscrapyard 2 years ago
Correct me if I'm wrong, but this is showing a gear generating process where the tool is a rack tooth profile (as in straight sides) and the table is passed across under the tool as the gear blank is being rotated at the same time by linking it to the table cross feed drive. This will generate one tooth with correct curved sides. The table is then brought back to the start position, the gear is indexed one tooth division, and then the process is repeated. I'd like to do this on my shaper.
flyingscrapyard 2 years ago
I'd like to see the gear train and dividing setup to do this as it is fairly complex. The beauty of it all is one rack profile tool will cut any number of teeth gear to the correct profile. With the right setup, it should also be able to cut bevel gears as well.
Please Rattycorner, show us another video of the gear train and dividing setup used to do this. It has become a lost art. Also the mathematics required to calculate the gearing ratios needed to get the roll of the gear correct. Well done
flyingscrapyard 2 years ago
I've been occupied on lots of other things since I posted that video. I had made another video to try to explain it better when I cut the pinion that it was designed for, but screwed up the uploading to youtube, then deleted the file before I realised that the clip hadn't appeared...
That pinion, by the way was a 14 tooth 20 degree PA, stub form, 22DP pinion for the carriage of a Hardinge HLV lathe that I'm refurbishing. It worked out perfectly.
rattycorner 2 years ago
(continued)
I'll get the original jig off the shelf and set up the camera on a tripod so that I can show the component parts and explain the workings and maybe show a better picture of what's actually happening, then try to edit the clips together to make a more useful video.
Watch this space :-)
rattycorner 2 years ago
Many thanks. I'll look forward to that with great interest!
flyingscrapyard 2 years ago
still watching. LOL
ukracer999 2 years ago
No gear train is required, the usual way to do this on a shaper is to machine a pulley a cable thickness less than the required average contact diameter and wind a single turn of cable around the pulley, anchored to the pulley in one place and anchored to a stationary point at each end. Normal table crossfeed gives the correct rotation with this method Steel tape appears to be used rather than cable here. Look up info on gear cutting to find out the correct contact diameter.
ValExperimenter 2 years ago
too me it looks like the table moves to the right, the tool moves down and the gear itself turns.
If the tool is shaped like a gear why not just feed the tool down until final depth then bring it back up rotate the gear and start over on a new tooth.
???
UUttis 3 years ago
think of it this way, you don't shove an entire hamburger in your mouth at once when you eat one right? you take it one bite at a time until you are done and then go get another burger and repeat the process. You do the same thing when machining something, bite after bite until you get what you need.
alderaforall 3 years ago
well of course but both ways i describe take small passes. I just wanted to know what was acually happening in this video since its shaky and blurred its har to see.
If the tool has the shape of the final gear it doesnt make any sence to move the table and the gear while machining one tooth. That may not be the case either maybe it just looks that way? Maybe it is like fowlera7 says but to me it looks like more is going on.
UUttis 3 years ago
I am not positive but I don't think the table is moving at all. Looks like the groove is cut to final depth and then the gear is indexed.
alderaforall 3 years ago
if the table moved side to side the gear would be junk.the table moves up to the tool and the gear is rotated by the jig used to hold it.this is the longest way to cut a gear even in bress.
schoonymopar 3 years ago
Care to explaine what we are seeing? I can see the crossfeed screw is turning, is the work advanced left/right? is the gear turning? is the tool feeding down?
UUttis 3 years ago
It looks like an involute gear is being generated, not cut. The cutting tool is a single tooth rack profile with clearance not an involute. You do see the table move across and the pinion turn. As the table moves across, the pinion is turned by a pulley behind to simulate the meshing of the gear with a rack. because there is only a single rack tooth the gear needs to be indexed,
ValExperimenter 3 years ago
Very Nice, why didn't school teach us that in shop, I've used shapers in the pass but nothing like that!
beetsareback 3 years ago
Could you do a video explaining the setting up for generating a gear? I would like to do this sort of thing but it is difficult to find anyone who knows how. There would be some interesting calculations to get the dividing head to turn at the right amount as the tool passes over. Have you cut bevel gears like this as well?
flyingscrapyard 3 years ago
I will try to have a go at it but it might take a month.
rattycorner 3 years ago
Shapers are very versatile machines that can accomplish an amazing range of work . Most of us only use 'em for quick roughing, or some simple plane surfaces. Nice to see 'em doin something more challenging.
raherecolston 3 years ago
BLOODY GOOD WORK MATE!
cosast54 4 years ago
Did you grind your own tool bit?
If so, where did you find a template for the involute profile?
I have been looking for a template which I can print out to grind a tool bit.
TheFartenator 4 years ago
I ground the tool bit with a surface grinder. The bit is a 14.5° ACME type cutter with 2.5° of relief. I got the dimensions from Machineries handbook. The involute form comes from indexing the vertical cutter across the blank as the blank is rotated.
rattycorner 4 years ago
Ah ok, thanks. I didn't see that the gear was turning as the shaper advanced.
TheFartenator 4 years ago
'twas a fairly lousy picture. When I do the pinions that this rig was the feasability study for, I'll try to rig up some better lighting etc.
rattycorner 4 years ago