RF 45 clone: X axis not very good

A

Abowie

Registered
Registered
Joined
Sep 11, 2019
Messages
40
I have a lot of backlash in the screw on my mill, and it gets quite hard to move towards the end of the travel.

I've had the gib out and cleaned it up a lot and it is now fairly smooth.

I'm considering fitting a ball screw for the X axis, hoping that this might help improve the performance.

A couple of questions.

Firstly, am I correct in assuming that a ball screw is a better option?

Looking on EBay ball screws seem to be readily available, but the screw in my lathe is 900mm long but only 550mm of that is threaded. The EBay screws don't seem to have any additional material on the ends for fitting handwheels etc, and I do a lot of my stuff manually.

I'm assuming that the screw diameter should be the same as that currently in my machine? So is 16mm or 5/8" appropriate?

Anyone done this and can help point the way for me?

Cheers

AB
 
I'd be concerned that the ways are worn in the middle and with the gib snugged down the table gets tight at the ends. If this is NOT the problem, the Ballscrew might be your answer. Your lead screw may be the one with the wear.
 
Abowie, It is possible (likely) that T Bredehoft has the right of it. It is just as likely there is no problem with your leadscrew, and you may be looking at wear on your dovetails/ways, or, there could be crud/corrosion that is binding up your table travel towards the ends. The first step would be disassembly and inspection of your precision surfaces and your leadscrew/nut. Once you have isolated the culprit, then remediate the problem, or order the parts which need replaced.
 
I agree that you need to make a diagnosis before planning a fix. More than a few tables sag on the ends; I would check to see if your table is actually flat.
 
OK thanks for the advice. I shall strip the mill this weekend and have a look.

It's only a year old and I bought it new so hopefully it's not too worn.

Having thought more about the length of the ball screw am I correct in assuming that I can machine off some of the thread in my lathe to get the length of material i need at the end to attach my handles.
 
Only a year old? It’s nice to have this info up front. My old RF30 was pretty stiff on the ends of travel and I pulled the lead screws and cleaned the super funky cosmolene like grease off and it is 100% better. And as far as play, the X and Y both have split nuts that have screws that can be adjusted. But don’t get carried away, this is a manual machine, it has some play like atleast .007 lash. My brother who worked as a machinist didn’t worry about it because most of the old worn out stuff he had to run sometimes had .500 lash in the wheels. Get yourself a DRO, then it’s not so crazy keeping track.
 
If it’s that new I would definitely clean the heck out of it.
My 1980 RF30 clone still had cosmoline all over it when I bought it last year!


Sent from my iPhone using Tapatalk
 
Took out the X axis gib. Looked to have been hand scraped using some sort of stone axe head.

I have a nice set of stones I inherited from my Grandpa. I have fixed the gib and man does the X axis run nicely now.
 
Abowie,
Excellent! I am glad you isolated and remedied the problem.
 
This thread was a great help to me! :cheerful:
Thanks for the info you guys!

I bought my 2nd hand RF-30 about a quarter of a century ago and it was so stiff - IIRC I only tested it 1 or 2 times.
I'm betting the guy I bought it from never really cleaned it!

We'll see! ;):encourage:
 
You must log in or register to reply here.
Back
Top