Harrison Milling Machine

[Pete O]

Looks very nice indeed.
The usual way to reduce running when spraying enamel is to apply a thin 'tack' coat- just a wave of the gun over the surface really, like a guide coat for sanding- and then spray your usual coat over that whilst it is tacky. wondering of you did that? Very good looking result you got in the end though.

[Pete O]

Also just a guess but I would expect to find the right-hand threaded lock on the left-hand side of the machine, and vice-versa. That way you would pull the handle up to lock. The other way around, gravity and vibration would always be locking the screws up when you want them free.

[Zoot Suit]

"The other way around, gravity and vibration would always be locking the screws up when you want them free"


Hi Pete O, I did ponder on the exact same thoughts after I had put the knee back.  I think I will swap the clamps around before I go any further.

Thanks to everyone else re the comments on the paint.  It is OK.  I could have spent loads more time on it and achieved a flawless finish but the problem is time, I have lots of other projects on the go and other draws on my time and so have to be realistic.

It is still a million times better than it was before.

Interestingly I found that it had been repainted twice before.  Over the original grey was another grey but one that is much paler.  On top of that was the green.  

I will post an update once the various parts have arrived and I am ready to finish off stage one.

John

[malben]

I have a Harrison mill manual pdf I can forward to you or anyone who wants one.

[Zoot Suit]

Thanks for the offer malben. I bought a pdf version myself a few weeks ago

I have a full version of Adobe Acrobat on by work laptop so I have OCR'd it so now I can do a word search if I want to find a specific item or topic.

If yours isn’t a searchable version let me know and I can email it to you. Likewise to anyone else who may need a copy.

John

[Zoot Suit]

I took this part apart today, it was the only bit I hadn’t touched yet and I assumed that it would just need new bearings.  Its the drive for the knee.  It was covered in grease and I didn’t expect corrosion.






After all of the grease was washed off there was a lot of end float and once apart and cleaned up it seems that at some time in the past it has been subject to moisture.

The inboard end is corroded and is loose in its bushing.  Because the drive pinion is on a spline that is the same diameter as the shaft, I cant machine the corrosion off and make a smaller ID bush.

By chance I found a piece of EN24T in my box that is the same diameter as the largest part of the shaft (one inch) and it is about 3/4" longer than the shaft.  Perhaps fate is telling me to make a new one?




Close up of corrosion




Its fairly simple lathe work except for the splines on both ends.  I am new to machining splines so I am looking for advice.  I am thinking that I could make a form tool once I have figured out the right shape and then figure out how to index my lathe chuck and cut the splines one at a time with the form tool in the tool post.  Any better ideas?  Also, what is the best source for establishing the geometry of the splines so I can grind a tool?

John

[awemawson]

A/ Machine shaft down below the level of the corrosion

B/ Turn up a bush that would be a sliding fit if you could get it on (but you can't !)

C/ Slit the bush

D/ Silver solder the bush onto the shaft tying the two halves together with wire as you do

E/ Machine bush / shaft assembly back to original size


Simples :)

[Zoot Suit]

(06-11-2017, 02:27 PM)awemawson Wrote: A/ Machine shaft down below the level of the corrosion

B/ Turn up a bush that would be a sliding fit if you could get it on (but you can't !)

C/ Slit the bush

D/ Silver solder the bush onto the shaft tying the two halves together with wire as you do

E/ Machine bush / shaft assembly back to original size


Simples :)

Doh!  Of course it is. 

Thanks for the prompt awemawson, I feel a bit dim because I have done that once before. 

My excuse is that I was preoccupied in pondering my piston question in the "General" section.

John

[hermetic]

You can always trust Andrew to come up with simple brilliant repair ideas! I think I might be tempted to split the bush in two, and then fit it. I was lucky with my Harrison, the only corrosion was in the table thrust bearing, but it had spent more time standing in the metalwork shop at my old school that it had actually being used! Keep up the good work, it is looking excellent, and when complete, it will be a joy to use. If you have the manual you will know that most (but not all) of the nipples on the machine are for an oil gun, not a grease gun. When I finally bought one and went round the machine pressure oiling it, the difference was nothing short of astounding!!
Phil

[hermetic]

I didnt read andres post properly, he does split into two halves DOH!