Milling machine spindle repair

[scottmk1]

So the part of my milling machine saga is the spindle, the splines are worn in one particular area where the hub that drives it makes contact when the quill is fully retracted. The area of wear is around 60-70mm long and it’s probably 1-1.5mm deep.

This is an expensive part to buy, £1750 to be precise, so I’m looking at possible repair options. What’s the thoughts on brazing or building up with a metalizing spray? Would the risk of distortion be too much? If so what other suggestions do people have?

 

[500e]

@Brad93

 

[gaz1]

id say build back up with hard weld rods and then grind off

but the issue of heat maybe a problem

 

[Barking Mat]

How much to have a new one machined ?

Just a thought ?

 

[Brad93]

Spray fuse or brazing. There will be distortion but a hell of a lot less than a resistance welding method.

Brazing would work you would need to be careful with your heat and it could wear a bit quick unless you use a harder brazing material containing nickel or aluminium.

Your other issue is machining.

If you weld, braze or spray, ideally you would bring the area down enough so that when machining, you're not at the zone where the bond between base metal and filler metal is.

Not so vital with spray fuse as it's designed to be applied in thin sections.

You'd want a pure nickel consumable.

I'd give either a go, but only on the basis of = it's currently scrap, so you have nothing to lose and everything to gain.

If it's not completely scrap, then try a repair method such as belzona 1111 applied correctly. It may work in that application if applied with a good former and a post cure.

 

[Barking Mat]

id say build back up with hard weld rods and then grind off

but the issue of heat maybe a problem

If you built it up you'd still need the splined machined.

 

[Barking Mat]

Couldn't that be done with a lathe.

Followed by a mill with a rotary table ?

Just thinking out loud.

 

[Brad93]

How much to have a new one machined ?

Just a thought ?

Spline, two absolutely critical bearing seats, plus an internal taper. All hardened and ground.




Probably £1750

 

[Barking Mat]

Spline, two absolutely critical bearing seats, plus an internal taper. All hardened and ground.




Probably £1750

Hardened and ground, hadn't thought of that eventuality.

 

[500e]

Expense is relative

 

[Barking Mat]

View attachment 339797Expense is relative View attachment 339799

Yeek.

 

[500e]

Close to 10K

 

[Barking Mat]

Close to 10K

What the hell is that ? 10 k.....

Silly me, helicopter ?

 

[Kram]

Is there enough meat to turn the splines off and shrink fit a spined sleeve? Distortion would be much less I imagine.

 

[minimutly]

Is there enough meat to turn the splines off and shrink fit a spined sleeve? Distortion would be much less I imagine.

I'd be making a new pulley with thicker sections, machining the splines to suit. I doubt they're hardened.

 

[addjunkie]

Id have a go with belzona 111 or Devcon, there is another one corracote or something like that, its not vynl but a hard coating that can be machined. Often used for fixing pig launcher door seats

 

[Barking Mat]

I read an article about Landrover fairy freewheeling / engaged front wheel hubs some years ago.

Bloke had a similar issue with worn spines.

His bodge was, angle grinder, some high tensile nails, ground them down to shims, hammered them in.

Total cost, less than a quid and his time.

Thought it was quite imaginative.

Not hugely relevant though.

 

[Agroshield]

...the splines are worn in one particular area where the hub that drives it makes contact when the quill is fully retracted...

All of the suggestions are only fixing, at very best, half the problem. It has worn because the drive pulley spends 95% of its time in that position. However you weld, braze, epoxy, etc. it up, the drive pulley will then spend 95% of its time of the repair section (which is never going to be as good as the original).

You need to look at the assembly as a whole and see if there is any way of re-engineering the drive system so the pulley spends its time driving another part of the splined shaft: either double its depth so it drives above and below that area or extend the quill permanently so the pulley never reaches that bit. You can put some kind of collar around the quill that is bolted to the underside of the head casting if there is any serious loss of rigidity.

 

[Brad93]

All of the suggestions are only fixing, at very best, half the problem. It has worn because the drive pulley spends 95% of its time in that position. However you weld, braze, epoxy, etc. it up, the drive pulley will then spend 95% of its time of the repair section (which is never going to be as good as the original).

You need to look at the assembly as a whole and see if there is any way of re-engineering the drive system so the pulley spends its time driving another part of the splined shaft: either double its depth so it drives above and below that area or extend the quill permanently so the pulley never reaches that bit. You can put some kind of collar around the quill that is bolted to the underside of the head casting if there is any serious loss of rigidity.

If you spray fuse it, it will be be better than the original.

 

[Munkul]

What is wrong with running as-is? Are you getting chatter from cutters? Or does the quill no longer run smoothly?
If it's an older mill, run it for a few more years and then trade out?
Not everything is economically viable to maintain for ever...