Feed rod bearing

S

Shawn_Laughlin

Registered
Registered
Joined
May 22, 2019
Messages
89
I have a grizzly g0791 lathe/mill and the tail stock end of reed rod has some play in the block. Either the feed rod is bent and that has caused the bore to expand or the bore is too much and the rod had play. When I run it on high speed it vibrates the hell out of everything. I can even feel it on my feet through the slab it’s bolted to.

I have a new fed rod but don’t see the point in installing it into a sloppy hole so was wondering if anyone had thought about or gone through with adding a bearing? It would greatly reduce wear for sure and should be be easy finding a bearing because the shaft is 19.95 mm so a 20 mm bearing should work?
 
Thanks rgray. I was actually going to go with a self lube plain bearing like that but then I started thinking roller bearing. Does anyone use rollers? I would think any sealed roller bearing would work as long as I have enough material to bore out a wider hole and not effect the integrity of the block?
 
I didn't know what a g0791 lathe was like but it looks like it's the same as mine but mine is lathe only.
I don't think there is room there for a ball bearing and don't think the shaft would be hardened enough to survive a needle bearing running on it.
Possibly could come up with a bearing that would fit the block and then you might have to machine the end of the feed rod smaller.
That's lots of work, and bronze bushings last a long time, so I'm not sure it would be worth the trouble.
 
I was going to try to find a short bearing I guess you would call it but after looking there isn’t any,at least I can’t find one, that will fit without reducing the strength of the block so ima go with one of those graphic plugged bushing like abovein the second post. All mine is,is a g4003g lathe with a 3/4 hp gearhead mill in the center,which I’m very impressed and surprised after reading all the negatives about lathe mill combos.

Since we have the same or similar lathes I got a question...... where my feed rod goes through the apron or saddle there is a follower block that that the feed rod passes through for the auto feed,I believe, and mine has a lot of side play,I mean like on the + side of 1/16” all the way around. Is yours like that or does that not sound right? I thought about adding a bushing there but I’m kinda worried that it would create noticeable drag when moving carriage manually?
 
Mine is an M1112 shop fox. Same as a g4003g and had the tan paint scheme before grizzly had it.
When I engage the feed my carriage is locked in place and there is almost no movement.
The carriage handle will only move about 3 lines and if looking around behind that movement is the play between the gears and a small forward aft movement of the worm on the feed rod.
My lathe has a 11/2012 build date on it.

I did have some slack in my lead screw at one time and had to replace the roll pin where it couples together at the QCGB.
 
'Scuse my ignorance, is a Feed Rod similar to a Lead Screw?
 
T Bredehoft said:
'Scuse my ignorance, is a Feed Rod similar to a Lead Screw?
Click to expand...

When your looking at lathes and there is two or three rods, then one will be a feed rod.
On our g4003g variants the low rod is on the forward reverse switch.
Middle rod is the feed rod, and it turns gears into the apron and feeds the carriage and cross slide.
Upper is lead screw and it is like any other and drives the carriage with the half nuts.

Plenty of lathes come with only a lead screw and you just feed with the half nuts engaged whether you're threading or not.
 
I’m glad you asked about the gears but let me first answer question. The block that the worm gear mounts to,I think it’s mounted to the block,that block where the feed rod goes through.tge hole is about an 1/8 bigger than the rod so I can push and pull and the rod move towards the baxk splash and back towards me.

The rail that mounts to the bed i think was mounted too high bc I have about 12 or 13 lines of slack. I mean can rotate the wheel almost halfway around,for sure more than a 1/4 way around before the carriage thinks about moving. And I was thinking that was causing the diagonal lines in all my turnings.

I think I just had back luck with this machine bc the compound gib came about 1/4” short so both screws don’t touch it together and you can tell where the cross slide was dropped and it had ding on one end and that lead screw was bent and I bent it back the best I could. It’s somewhat smooth until it gets to about the last 1” of movement towards me that it wants to bind up but I can live with it. But the disks are no good to me bc there’s just too much slack in all of them. It’s either no backlash and tight as hell or nice and smooth with lots of backlash.

I have no choice but to live with the carriage backlash unless I remove and drill and tap new holes to relocate it,which I’m not opposed to doing,it just sucks being a brand new unit. Mine was built in like the end of 2018 if I remember correctly
 
You must log in or register to reply here.
Back
Top