9x19 power feed lever issue?

[BrooklynBravest]

I have a G4000 9x19 from grizzly.

For whatever reason the power feed seems to be malfunctioning.

When I engage the power feed lever sometimes it does start moving the carriage but eventually it just stops.

Most times the carriage just doesn't move at all.

The half nut lever and the lead screw still work fine.

[John Evans]

Call Grizzly tech! I would say a sheared pin/key or a gear missing teeth. Most likely the pin/key if it tries to move once in a while.Somewhere in the apron if the lead screw and half nuts work ok.

[tornitore45]

Grizzly tech support will have no clue of what is wrong, and will just speculate like we all are doing; whatever it is wrong it will most likely require you remove the apron to fix it.

If you have the mechanical aptitude to use the late and build stuff, you certainly have the ability to remove the apron which is easy after removing the lead-screw.
The innards operation is self evident.
The symptoms indicate a gear with broken teeth. That can only happen during a crash or if the lever mechanism that prevent engaging both the half nut and the worm gear is maladjusted and has allowed to engage both.

I suggest you take the entire apron apart and ponder over the operation, then reassemble tightening up the half nut dovetail and lubing, (usually they are sloppily assembled with lots of play because they do not want to spend too much time) adjust the movement limiting screws of the 1/2 nut lever making sure the worm-screw is kept from engaging when the 1/2 nut is. Also use the lead-screw to adjust the 1/2 nut movement is just right, not too loose or biting the lead-screw. If there is any crud or paint under the 1/2 nut dovetail bars, remove it.

Reinstalling the apron is straightforward but attention is needed to position the lead-screw RH support to be vertically in line with the 1/2 nut. Run the carriage all the way back, clamp the lead-screw closing the 1/2 nut before tightening the RH support in place.

[BrooklynBravest]

Alright so I finally disassembled the apron and the issue was apparent.

The gear that ultimately contacts the power feed to the lead screw is totally shot.

Good news is it's only around $20 shipped but I'm havin some trouble identifying it by the parts diagram for the G4000.

The part I think it is says 41T gear, I counted 42 unless I'm crazy or counting wrong.

I'm not really sure how to get the lead screw back on either. To remove it I punched out the pine but I had to use a channel lock to wiggle it out of its position. Obviously tapping it back in is a high risk to bend it so should I just try wiggling it back in?

[spro]

I counted 42 also. There are indications of an original misalignment. There is little wear in the center (until gear chips got in). The gear straddles the screw so it would be out of sync if riding the edge. Depends upon the lathe but if the leadscrew is keyed, it will act as gear cutter. Remember that QC boxes and tail support of the leadscrew are often shimmed to allow linear alignment.

[spro]

I really want to delete this for it certainly doesn't apply to many lathes. Gave it a shot (oh dear) gave it go. I targeted upon the gear wear. oops, Focused on the wear. dang

[tornitore45]

Item 27 on the exploded drawing is 41 teeth
Item 39 is 42 teeth.

Looks like a 42 teeth gear was selfmachining to reach the 41 teeth diameter
No gear in the apron engage the leadscrew.
The leadscrew drives a keyed, sliding, worm gear that engage one of the gear. Can not say which from the drawing.

Either the factory put a 42 gear where a 41 was called for. Unlikely since even a Chinese worker would not use such a heavy hammer.

Or you did not identify the correct gear on the drawing. Take another look.

The erratic engagement is clear from the section where most teeth are gone.
Did you have any crash? That may explain the broken teeth.
When you reassemble the apron you need to be looking for reasons why the gear worn out so badly, was it rubbing on something. We can't really help you on this assessment.
If the gear in question is the last on the chain, the one that engages the rack, then is important that the rack is vertically positioned to engage the gear fully, if the rack is too high that only the teeth tops are working and prone to wear.

Regarding the pin connecting the leadscrew to the gear box. If the hole was drilled on the exact diameter, the pin would go in at both orientation 180* apart. On my lathe the hole is off from center just enough to allow only one line up position. Something to be aware.
The pin is a roll pin and I doubt it will share in case of trouble. I replaced my with a brass screw and nut judiciously weakened to the point, I hope, it will share on a crash but would not break in the middle of an operation on a part I already worked 20 hours on it. Your choice. If you want the roll pin, just replace it. Is a $0.05 item you can get at Home Depot for $1.95.

Reassembling make sure the lead screw RH support is lined up with the 1/2 nut. Move the carriage all the way Right, close the 1/2 nut to grab and locate the leadscrew where it wants to be, then tighten the support crews, check that the support is able to reach the leadscrew level and is not binding before is even tightened. If you need shims in the back make them.

I am perfectly satisfied with my G4000, but it took many modifications, improvements and TLC before becoming useful.

[BrooklynBravest]

Item 27 on the exploded drawing is 41 teeth
Item 39 is 42 teeth.

Looks like a 42 teeth gear was selfmachining to reach the 41 teeth diameter
No gear in the apron engage the leadscrew.
The leadscrew drives a keyed, sliding, worm gear that engage one of the gear. Can not say which from the drawing.

Either the factory put a 42 gear where a 41 was called for. Unlikely since even a Chinese worker would not use such a heavy hammer.

Or you did not identify the correct gear on the drawing. Take another look.

The erratic engagement is clear from the section where most teeth are gone.
Did you have any crash? That may explain the broken teeth.
When you reassemble the apron you need to be looking for reasons why the gear worn out so badly, was it rubbing on something. We can't really help you on this assessment.

If the gear in question is the last on the chain, the one that engages the rack, then is important that the rack is vertically positioned to engage the gear fully, if the rack is too high that only the teeth tops are working and prone to wear.

Regarding the pin connecting the leadscrew to the gear box. If the hole was drilled on the exact diameter, the pin would go in at both orientation 180* apart. On my lathe the hole is off from center just enough to allow only one line up position. Something to be aware.
The pin is a roll pin and I doubt it will share in case of trouble. I replaced my with a brass screw and nut judiciously weakened to the point, I hope, it will share on a crash but would not break in the middle of an operation on a part I already worked 20 hours on it. Your choice. If you want the roll pin, just replace it. Is a $0.05 item you can get at Home Depot for $1.95.

Reassembling make sure the lead screw RH support is lined up with the 1/2 nut. Move the carriage all the way Right, close the 1/2 nut to grab and locate the leadscrew where it wants to be, then tighten the support crews, check that the support is able to reach the leadscrew level and is not binding before is even tightened. If you need shims in the back make them.

I am perfectly satisfied with my G4000, but it took many modifications, improvements and TLC before becoming useful.

Yea item 39 vs 27 is my exact dilemma. Its hard to see what lines up in the drawing as the right gear but obviously it calls for a 42 and all of us are counting 42.

As far as the gear being shredded, and trust me its bad, I would assume it to be crash related. But, its a 20 year old machine and I am only the owner for 2 years.

I'm guessing it wasn't so bad when I first got it, and maybe thats why the original owner I bought it from wanted to sell it. Once the teeth are slipping I can only assume the problem compounds worse and worse at a faster and faster rate.


I think I figured out my confusion. They drew it backwards in the drawing, and the arrow that points to where the gear goes on the illustration is in a U-turn shape. I assume its implying it spins around from how its drawn because they couldn't fit it on the page or something. Seems silly but im pretty certain its 39 now.


Bummer because that one is $30 instead of $20

[spro]

Wait a minute.. it is 42. Don't go by one post as mine which neglected the gear rode on the worm and not on the lead screw. That seemed minimal to my description of contact. I actually tried to post a larger explanation but when I hit the wrong key and it disappeared, it was time to go. I was wondering about the 41 also. There is a possibility which I hesitated to mention because of alignment and straddle of the worm. Is it possible that the replacement gear is 41 because they expect it to run at the outside when the original was worn? If this is some easy solution with slightly thicker teeth, it doesn't float here. You/We want this to work as the engineering provided this base. When it comes to possible or major clues there are a series of decisions. One relates to the other. How far do you want to take this back BUT all the time, that gear wasn't riding correctly.
I'll stick with that, until it is shown that the power feed was engaged often to less than full engagement. little adjustments prevent major damage.

[tornitore45]

If we can not trust the drawing the only secure thing is the apron itself.
You can accurately measure the the center to center distance and then calculate the modulus=diameter in mm divided by No of teeth, the correct No of teeth gives a round number. On the other hand if the machine has worked for 20 years the No of teeth was probably right, UNLESS a 42 was installed in place of a 43, assuming other dimensions match (hole, hub, thickness). That would last just about 20 years of hobby work with the teeth engaging 1.5mm instead of 2mm and rubbing instead of rolling like gears are supposed to work. Most of the 9x20 gears are Modulus 1 meaning the tooth dept is a trifle over 2mm.

[BrooklynBravest]

I was able to figure out the drawing and I also contend the other gear and that one was the 41T.

I ordered what should be the correct gear for $30.

Hopefully when I put it all back together I will be back in business.

It's rare I use the lathe but it's been having problems for a while.

[BrooklynBravest]

Near gear came.

Swapped it out. Runs great now.

Only part that was a pain was getting the lead screw back on.