RF-30 Collet Problem

[Bill_Rittner]

While cleaning up the recently purchased used RF-30 I discovered an R-8 collet would not go in past the pin. I got a telescoping gage up into the bore above the drive pin and the bore checked at 0.950". The collet tolerance is 0.9490" to 0.9495". So I concluded that the drive pin stuck out too far. I removed the quill and the spindle and repaired this problem. Has anyone else ever had this problem with the RF-30? I have had it on a Bridgeport once.

 

[Silvergoose]

Bill, it is strange that you post this at this time. I am having trouble with my collects going in to the quill and it seems as though they become stuck when I try to change them out. I to have a RF-30 that I have used for the last 8 years.

I hate to ask,but was it difficult to remove the spindle? What is your plan for the repair?

Thanks for any insight.

Good Luck on your repair

 

[Blogwitch]

Normally for an R8 fitting, the dog nosed grub screw (the pin on the end being the locking pin for your fitting) is locked in position by a normal grub screw behing it. The grub screw, if it comes loose will still stop the dog nose from screwing out to a certain degree, but won't stop it screwing into the quill and giving you the problem you seem to have.

I could let you have a diagram showing how the Bridgeport is stripped and the pin changed, but don't know if it is the same for the RF. The Bridgeport replacement takes no more than 10 minutes.

Hope this helps

John

 

[Silvergoose]

John, thanks for the offer, but your explanation of the construction will allow me to me to move forward.

 

[Bill_Rittner]

http://www.fignoggle.com/machines/r...ill-drill-spindle-quill-removal-procedure.htm

The above link will get you started removing the quill/spindle assembly and removing the spindle. I found my key to be ground flush with the spindle od and staked in 4 places. I couldn't drive it out with a punch so I assumed it was threaded in, so I drilled it out. I will install an M5 screw when I determine it will fit. Hope this info helps.

 

[Bill_Rittner]

It turns out that the threads for the pin in my RF-30 spindle are 5mm x 0.8. I drilled out the original screw that was too long preventing the collet from seating all the way into the spindle. Then I re-tapped the hole and used a 5mm x 0.8 socket head cap screw cut to approximately 0.270" long. I used a belt sander to grind the tip of the screw to 0.150" wide to fit the keyway on an R-8 collet. There is plenty of clearance for the cap screw head so I left it. I used thread locker and tightened the screw down checking that a collet fit properly. Now it is time to reassemble the quill/spindle unit to the head.

 

[Silvergoose]

Bill, thank you for the time you spent downloading the RF quill photos.

I will save this until I have the time to tear in to the mill.

Again, thank you.


Best of luck

 

[Blogwitch]

Bill & S,

5mm dog nose grub screws have the correct diameter tip to fit the groove of the R8 fixture perfectly.

These are from the UK, but I am sure you can get them in the US much cheaper. I didn't use the SS ones as they have a tendency to gall and be difficult to remove once tightened.

http://www.westfieldfasteners.co.uk/A2_ScrewBolt_GrubDog_M5.html

John

 

[Bill_Rittner]

Thanks John. These screws will not work on the RF 30 because the wall thickness at this point is only about 3/16". This doesn't allow for a locking setscrew. I used a 5mm socket head cap screw cut to length and filed 2 flats on the end. This way you have the head to tighten against the spindle and thread locker.