New(ish) to millling machine ownership. Spindle(?) damage

[Jimmy c]

Hi all, this is my first attempt at any forum let alone a machining one so sorry if this isn't as it should be or WHEN any of the terminology is wrong.

I have done some very basic mill/lathe work in the past but nothing serious. It's something I have wanted at home for a while to allow me to explore machining as I have a drift car that definitely could help out!

My work has moved from manual to CNC machining and there was no real plan for the old machines so I offered to take one off their hands for the brilliant price of £0. I now have a Excel PDM-30 which the internet doesn't throw up too much about irritatingly.

I went to remove the R8 collet and the draw bar took some serious wacking before the collet would fully release, moving millimetres a time with serious force. I assumed a build up of crap as the same collet was used on this machine for years. Once out I cleaned all surfaces, tried to put it back in as the same massive force was needed. I assumed the collet was damaged so I took it to work to see if it fit in another machine and unfortunately it did beautifully.

I can insert it and it moves freely in the keyway(?) then it reaches the resistance. To identify where it was catching I used a marker to see where it rubs off. It seems to be all the way around the perimeter, with some concentrated areas, see photos.

I have tried using some 120 grit inside the spindle(?) to move any stubborn metal areas that may have been damaged with the plan of moving to around 600 grit but it doesn't seem to be effecting anything (I dont feel like i should be doing it at all). The metal in the spindle(?) may well be to much for sandpaper.

Any smart ideas? Ideally I'd like to repair rather than replace and please ignore how the post sounds I am capable with tools, the milling machine is just a bit new to me.

Sorry if this was all a bit wordy, Any feedback or help would be brilliant!

 

[Pete.]

Probably someone has pulled the collet in on the drawbar without locating the pin in the groove. Usually this results in a jammed-in collet, mullered pin and possibly scored ID on the spindle. Try shining a light up into the hole and see what it looks like.

 

[Agroshield]

The machine itself is an example of a generic type, most widely known as 'RF30' or 'round column mill'. Warco sells it as the 'Major' in the UK. Grizzly in the US sell/sold them. You can also find it by looking for 'King PDM 30' (https://www.kingcanada.com/en/produ...ling-machines/pdm-30-milling-drilling-machine). The US instruction manuals tend to be better quality than the UK ones.

As Pete. says, the most likely cause is a deformed spindle key. A common thing to do on a Bridgeport, which originated the R8 taper, is to remove the key from the spindle altogether. If you can find a way of doing that, then repair to the bore, should it prove necessary, will be a lot easier.

One of those USB borescopes that plug into a phone would allow you to get some pictures up inside the spindle to see what the problem might be.

Edit: reading what you say about it going in OK until it then meets resistance, measure from the end of the spindle to the end of the key and then measure the same on the collet. Even in good condition, if the key in the spindle is too long (its end is too close to the end of the end of the spindle) it will interfere with the groove run out in the collet and bind.

 

[Jimmy c]

Probably someone has pulled the collet in on the drawbar without locating the pin in the groove. Usually this results in a jammed-in collet, mullered pin and possibly scored ID on the spindle. Try shining a light up into the hole and see what it looks like.

Hi Pete, Thanks for your input, see the attached. It looks pretty rough. Do you think this is a repairable inner bore or replacement part needed?

 

[Jimmy c]

The machine itself is an example of a generic type, most widely known as 'RF30' or 'round column mill'. Warco sells it as the 'Major' in the UK. Grizzly in the US sell/sold them. You can also find it by looking for 'King PDM 30' (https://www.kingcanada.com/en/produ...ling-machines/pdm-30-milling-drilling-machine). The US instruction manuals tend to be better quality than the UK ones.

As Pete. says, the most likely cause is a deformed spindle key. A common thing to do on a Bridgeport, which originated the R8 taper, is to remove the key from the spindle altogether. If you can find a way of doing that, then repair to the bore, should it prove necessary, will be a lot easier.

One of those USB borescopes that plug into a phone would allow you to get some pictures up inside the spindle to see what the problem might be.

Edit: reading what you say about it going in OK until it then meets resistance, measure from the end of the spindle to the end of the key and then measure the same on the collet. Even in good condition, if the key in the spindle is too long (its end is too close to the end of the end of the spindle) it will interfere with the groove run out in the collet and bind.

Hi Agrosheild, thanks for the info on the machine, that's a massive help! See attached photos on my reply to Pete, the scratching doesn't seem to be opposite the key so in my mind the key is not the culprit but I'm happy to be told otherwise!

 

[Pete.]

Hi Pete, Thanks for your input, see the attached. It looks pretty rough. Do you think this is a repairable inner bore or replacement part needed?

View attachment 368893 View attachment 368894

Looks like the locating pin is rotated. Personally I would remove it altogether.

 

[Jimmy c]

Looks like the locating pin is rotated. Personally I would remove it altogether.

Is there anything special to removal? Long nose pliers and some force with a side of heat if stubborn?

 

[Wedg1e]

Excel are a UK-based importer of Asian-made machines, run by an Indian gentleman I believe. They used to have 'Made in Britain' on their banner but got pulled for it as they were bringing in foreign machines and just changing all the data plates, then re-exporting them to places where the UK still had credibility...

 

[Agroshield]

Is there anything special to removal? Long nose pliers and some force with a side of heat if stubborn?

I hope I am not misreading your question, but just to be clear, you cannot remove the key from the inside of the spindle. You need to remove it from the outside and to do that, you have to drop the quill and look at it to see how it is made. The outer quill might have an access hole or slot in it, but if not, you have to remove the spindle from the quill.