Larry Gipson
11-05-2012, 3:47 PM
There are many threads on this board that cover this upgrade, but I didn't find one with pictures. I've ordered the cutter from Grizzly and some replacement parts from Jet. Until stuff gets here, I thought I should remove the old head and clean things up a bit.
I contacted Byrd and confirmed that the head offered by Grizzly would, in fact, fit the Jet. It's cheaper through Grizzly for some reason, but it's the same head.
First, I watched this video: http://www.youtube.com/watch?v=vBwmzacZFSs for the Grizzly 4 post planer. It's similar in construction, but not an exact match. It's really useful though.
The sequence is covered nicely in the video:
1. Take the top panel and dust chute off the machine, exposing the cutting head
2. Remove the 3 blades. (note: there are 2 springs per blade that should be taken out along with the long clamp that holds in the blade)
3. Put some wood under the head to support it as it's removed
4. Remove the belt cover, belts, and belt pulley. There's a capstan bolt that holds the pulley on. I found that a little PB Blaster and my impact driver made short work of freeing these bolts. I'm calling them capstan bolts for lack of a better word. They're made for metric allen stocks, either 6mm or 8mm in this case. There are socket sets that make this easy (example):
http://www.sears.com/craftsman-6-pc-metric-3-8-in-dr/p-00934448000P?prdNo=2&blockNo=2&blockType=G2
If the pulley is stuck, use a gear/pulley puller like the one in the 3rd picture (lower left) - example
http://www.amazon.com/TEKTON-5680-3-Inch-3-Jaw-Puller/dp/B000NPPB1K/ref=pd_cp_hi_3
5. Remove the wheel, cover, and 4 capstan bolts that mount the transmission (The transmission mount detail is seen in the 2nd picture from the bottom side.)
6. Remove the head and transmission assembly by tapping on the shaft where the pulley was mounted. This isn't so easy. Lubricate the shaft with something like PB Blaster, then it will come out with repeated taps. I was able to remove it with a small ball peen hammer and a block of wood. The head will be replaced, so it's up to you if you want to keep this shaft from being damaged. The wood saves the shaft. The cast iron on this side is pretty thick (1/2"?), so you'd have to hit it pretty hard to break it. It can be done though, so I'd use a smaller hammer and tap it a lot. Once it breaks free, it moves pretty easily. As you do this, the transmission will walk out of its mount.
7. At this point, the video says to drain the oil, then take the front off the transmission. I did this. All of the gears in the transmission came out attached to the front panel, so watch for that (right side of picture 3). Residual oil left in the transmission would have hit the floor, except I asked my wife to hold paper towels under it when I cracked it open. There are 2 alignment pins to watch out for (4th picture). A putty knife was enough to separate the front panel after removing the capstan screws. Be sure to buy a replacement gasket.
8. Now you'll have the transmission casing with the long heavy head assembly hanging off of it, captured though a hole with a rubber seal (bottom of 4th and 5th pictures). The bearing will very be holding very firmly to the (short) shaft of the head, held in place by friction and a spiral gear. There's a capstan screw holding this little gear on that must first be removed. Then the gear came off easily. I C-clamped the transmission to my assembly table so I could figure out how to remove this last bearing without breaking the thin cast iron of the transmission casing.
9. After looking at this for awhile, it became clear that I should worry about breaking this box by pounding so I decided to make a jig to simply press the shaft out of the bearing. This jig had to support the cast iron from the back while I did this. This jig can be seen in the 3rd picture (bottom). I used 2 pieces of angle iron with a 1 1/4" hole drilled in them to surround the shaft. The hole is beveled to match the bevel in the head and snugs up under the rubber seal (picture 6). Long bolts hold the angle iron to the tubing on top, which has a bolt directly above the shaft which makes the press.
I'm also fixing a transmission leak, so I'll replace this rubber seal as well as the gasket.
That's where I am.
There's been some discussion about using 50 wt oil as specified in the manual or regular gear oil. Yes, Jet tech support told me just to use automotive gear oil. I actually found that Lucas makes a really nice 50 wt synthetic gear oil used in 18 wheeler transmissions (and race cars! - picture 3 right). http://www.lucasoil.com/products/display_products.sd?iid=372&catid=22&loc=show It's a clear oil and seems to work.
I contacted Byrd and confirmed that the head offered by Grizzly would, in fact, fit the Jet. It's cheaper through Grizzly for some reason, but it's the same head.
First, I watched this video: http://www.youtube.com/watch?v=vBwmzacZFSs for the Grizzly 4 post planer. It's similar in construction, but not an exact match. It's really useful though.
The sequence is covered nicely in the video:
1. Take the top panel and dust chute off the machine, exposing the cutting head
2. Remove the 3 blades. (note: there are 2 springs per blade that should be taken out along with the long clamp that holds in the blade)
3. Put some wood under the head to support it as it's removed
4. Remove the belt cover, belts, and belt pulley. There's a capstan bolt that holds the pulley on. I found that a little PB Blaster and my impact driver made short work of freeing these bolts. I'm calling them capstan bolts for lack of a better word. They're made for metric allen stocks, either 6mm or 8mm in this case. There are socket sets that make this easy (example):
http://www.sears.com/craftsman-6-pc-metric-3-8-in-dr/p-00934448000P?prdNo=2&blockNo=2&blockType=G2
If the pulley is stuck, use a gear/pulley puller like the one in the 3rd picture (lower left) - example
http://www.amazon.com/TEKTON-5680-3-Inch-3-Jaw-Puller/dp/B000NPPB1K/ref=pd_cp_hi_3
5. Remove the wheel, cover, and 4 capstan bolts that mount the transmission (The transmission mount detail is seen in the 2nd picture from the bottom side.)
6. Remove the head and transmission assembly by tapping on the shaft where the pulley was mounted. This isn't so easy. Lubricate the shaft with something like PB Blaster, then it will come out with repeated taps. I was able to remove it with a small ball peen hammer and a block of wood. The head will be replaced, so it's up to you if you want to keep this shaft from being damaged. The wood saves the shaft. The cast iron on this side is pretty thick (1/2"?), so you'd have to hit it pretty hard to break it. It can be done though, so I'd use a smaller hammer and tap it a lot. Once it breaks free, it moves pretty easily. As you do this, the transmission will walk out of its mount.
7. At this point, the video says to drain the oil, then take the front off the transmission. I did this. All of the gears in the transmission came out attached to the front panel, so watch for that (right side of picture 3). Residual oil left in the transmission would have hit the floor, except I asked my wife to hold paper towels under it when I cracked it open. There are 2 alignment pins to watch out for (4th picture). A putty knife was enough to separate the front panel after removing the capstan screws. Be sure to buy a replacement gasket.
8. Now you'll have the transmission casing with the long heavy head assembly hanging off of it, captured though a hole with a rubber seal (bottom of 4th and 5th pictures). The bearing will very be holding very firmly to the (short) shaft of the head, held in place by friction and a spiral gear. There's a capstan screw holding this little gear on that must first be removed. Then the gear came off easily. I C-clamped the transmission to my assembly table so I could figure out how to remove this last bearing without breaking the thin cast iron of the transmission casing.
9. After looking at this for awhile, it became clear that I should worry about breaking this box by pounding so I decided to make a jig to simply press the shaft out of the bearing. This jig had to support the cast iron from the back while I did this. This jig can be seen in the 3rd picture (bottom). I used 2 pieces of angle iron with a 1 1/4" hole drilled in them to surround the shaft. The hole is beveled to match the bevel in the head and snugs up under the rubber seal (picture 6). Long bolts hold the angle iron to the tubing on top, which has a bolt directly above the shaft which makes the press.
I'm also fixing a transmission leak, so I'll replace this rubber seal as well as the gasket.
That's where I am.
There's been some discussion about using 50 wt oil as specified in the manual or regular gear oil. Yes, Jet tech support told me just to use automotive gear oil. I actually found that Lucas makes a really nice 50 wt synthetic gear oil used in 18 wheeler transmissions (and race cars! - picture 3 right). http://www.lucasoil.com/products/display_products.sd?iid=372&catid=22&loc=show It's a clear oil and seems to work.