I finished my second version of my R&P drive reducers and they work great. The only issue I have is that I cant keep the grub screws on the pinions tight. After about 2 hours of breakin they seem to break free.
I have tried locktite 222 (purple)
HF 42 (Blue)
and locktite 242 (blue)
I clean with acetone before each attempt. I then give them a chance to setup.
Here is the catch and I am wondering if this is what is causing the problems. The pinion gears are 3/8" The shaft is 1/4 with flats (D shaft). I machined a 3/8" to 1/4" reducer. It has a hole where the grub screw makes its way through. I am using longer grub screws since they have to get through the reducer.
The grub screws are stainless steel. Could this be causing the problem? I dont want to use locktite red on these as I dont want to start heating things.
grub screw issues
-
- 2.5 Star Member
- Posts: 210
- Joined: Wed May 04, 2016 2:31 pm
- Contact:
grub screw issues
Last edited by msimpson99 on Tue Oct 25, 2016 8:26 pm, edited 1 time in total.
- acourtjester
- 6 Star Elite Contributing Member
- Posts: 8148
- Joined: Sat Jun 02, 2012 6:04 pm
- Location: Pensacola, Fla
Re: grub screw issues
I don't know if you have the depth but you could try 2 grub screws one on top of the other I have seen this while taking pulleys off shafts. Similar to a jam nut on a bolt (double nut thing).
DIY 4X4 Plasma/Router Table
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PowerTig 255 EXT
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PowerTig 255 EXT
-
- 2.5 Star Member
- Posts: 210
- Joined: Wed May 04, 2016 2:31 pm
- Contact:
Re: grub screw issues
I thought of that. I dont have the depth. When building the reducers it has been a challenge to source the parts. I would have preferred a pinion with a 1/4" bore. This would allow for more byte of the grub or even two grubs.
These are 14-1/2 Pressure Angle to match the racks. I wanted to go with 20 degree pressure angle but I cant get the pinions I want for this. But, I can get some gear rod stock for 20 degree pressure angle. I can get 12" of this for $41. With this I can make my own and move over to 20 degree PA. It runs much smoother in my opinion.
These are 14-1/2 Pressure Angle to match the racks. I wanted to go with 20 degree pressure angle but I cant get the pinions I want for this. But, I can get some gear rod stock for 20 degree pressure angle. I can get 12" of this for $41. With this I can make my own and move over to 20 degree PA. It runs much smoother in my opinion.
-
- 2.5 Star Member
- Posts: 210
- Joined: Wed May 04, 2016 2:31 pm
- Contact:
Re: grub screw issues
Another thought. The excess of the grub screws stick out about 1/4". Can a locktihte a nut onto this?
- WyoGreen
- 4 Star Member
- Posts: 897
- Joined: Tue Mar 04, 2014 8:36 pm
- Location: Cheyenne, Wyoming
Re: grub screw issues
I think I'd try putting a nut on that excess grub screw length. It should act like a lock nut.
Precision Plasma gantry
CommandCNC Linux controller w/Feather Touch & PN200 hand controller
HT-45 plasma cutter
Plate Marker
Router
Laser
CommandCNC Linux controller w/Feather Touch & PN200 hand controller
HT-45 plasma cutter
Plate Marker
Router
Laser
-
- 2.5 Star Member
- Posts: 210
- Joined: Wed May 04, 2016 2:31 pm
- Contact:
Re: grub screw issues
The drive reducers are working really well. Its only the X-axis (Non Gantry) drive thats giving me problems.
I cleaned and re-applied 242 and added a nut shown here:
On the pulley I had only 222, so I removed both grubs screws (It has 2) and applied 242.
Im getting a little wiggle from the drives, but I think its the tension and the drive mount. I will improve these later. I have the actual no load backlash down to about .001 and repeatability down to abut .001 as well.
Both the grub screw and the main reduction pulley failed.I cleaned and re-applied 242 and added a nut shown here:
On the pulley I had only 222, so I removed both grubs screws (It has 2) and applied 242.
Im getting a little wiggle from the drives, but I think its the tension and the drive mount. I will improve these later. I have the actual no load backlash down to about .001 and repeatability down to abut .001 as well.
You currently do not have access to download this file.
To gain download access for DXF, SVG & other files Click Here
-
- 2.5 Star Member
- Posts: 210
- Joined: Wed May 04, 2016 2:31 pm
- Contact:
Re: grub screw issues
So far so good, I gave the blue Locktite about 24 hours to set and been working good for about 5 days. I think the problem arises from the fact that the pinion only has about 1/8" of threads. Seems like a bad design for a grub screw to hold something that is obviously goin
-
- 2.5 Star Member
- Posts: 142
- Joined: Thu Jan 31, 2013 11:40 am
Re: grub screw issues
If you can't get the correct pinion than I would also sleeve the outside of the hub if you have clearance which I think you must if you put a nut there.
That would be structurally much stronger. It would give you more threads to "push" on the shaft and more threads for the Locktite to hold.
That would be structurally much stronger. It would give you more threads to "push" on the shaft and more threads for the Locktite to hold.
-
- 2.5 Star Member
- Posts: 142
- Joined: Thu Jan 31, 2013 11:40 am
Re: grub screw issues
As a rule of thumb you want to have 1.5 times the diameter of your screw for optimum holding power.