Harrison Horizontal/Vertical Mill Restoration

[Carl Wilson]

I have now completely reassembled the Gryphon motor apart from installing the front shaft seal.

I put a small amount of Loctite 222 on the 4BA screws that secure the rear bearing retainer.

It should be fairly easy to pass the front seal over the shaft and into the recess shown here.

 

[Carl Wilson]

Suds pump also going back together.

 

[Carl Wilson]

Full marks to simply bearings. Ordered the motor seal yesterday at 15:21. It's here this morning. And to an "outlying postcode" too.

It's 24 x 15 x 7. For definite this time...

 

[Carl Wilson]

Front shaft seal in and Gryphon motor finished. Next job is to rebuild the feed gearbox.

 

[Carl Wilson]

This morning I commenced the gearbox reassembly. I'm going to refer back to the diagram of the gearbox I posted earlier, this can be found in post number 52 on page 3 of this thread.

There are two identical shafts in the gearbox and they sit one above the other. I started with the lower of the two that carries the gear driven by the Gryphon motor.

Both shafts have two different sized bearings, the smaller in each case being fitted at the end with the small woodruff key. I fitted this smaller bearing and the spacer, item 31, first. A few drops of oil helped to ease assembly. Next I slid the shaft into the gearbox and slipped the driven gear over the splines.

At this point I engaged the bearing into the bore in the gearbox and slid it into near final position. The larger second bearing was then driven onto the opposite end of the shaft and into the casting bore simultaneously.

The retaining circlip was fitted and the shaft position adjusted until there was 3mm clearance at the large bearing end between the bearing outer race and the edge of the bore. This is to allow the end cap to be fitted.

The cap over the first end has a cut out that aligns with the bearing oil feed drilling in the casting. Both these caps will be fitted with a bead of Loctite 574 flange sealant.

The shaft feels very smooth and runs true in the new bearings.

There are still a few outstanding jobs to do on the gearbox. I have to clean up the external transfer gears, clean up, strip and paint the transfer gear cover and machine a knurled 9/16 UNF retaining nut for the end of one shaft.

I'm at work until Friday now, so I will continue with the gearbox rebuild on my return.

 

[Carl Wilson]

Apologies for the recent dearth of posts.

Still rebuilding the gearbox. I've also been spending time reorganising my shop to facilitate getting the engine crane around. This will ease the continuing disassembly of the machine.

Yesterday I installed the new bearings to the leadscrew nut and worm wheel unit. One of the new bearings feels and sounds quite rough. I have made a short clip where I think you can hear the difference. Doubleboost doesn't need to worry.

I have ordered another bearing. Bearing Boys have offered me a refund if I send the bearing back. I don't really think it is worth it due to the postage.

 

[scottmk1]

What brand bearings are they?

 

[Carl Wilson]

They are Dunlop bearings from Bearing Boys. To be honest I think it might well have been fine. It isn't going to be doing a huge rate of knots on the leadscrew nut. You can't tell so well from the video, but spinning it up by hand there is a marked difference between the rough one and the others.

As the leadscrew bearings take the end thrust from the cutting forces, I don't want to take any chances, so I've just ordered another bearing.

I've fitted the pinion to the motor shaft now, complete with the spacer and oil seal. I can't fit the motor until I've got the worm shaft in as I need access to fit the bearing end caps. And I can't fit the worm shaft until the leadscrew nut is in...

 

[Carl Wilson]

The bearing for the leadscrew nut arrived yesterday. So I have now installed the leadscrew nut/worm wheel and bearing cluster. I used parts from my clamping kit to pull the assembly into the casting.

Next I fitted the end cap and spacer. These parts are retained by a 1/4 UNC dog point grub screw. This engages a peripheral slot in the cap. I used a drop of Loctite on the threads.

 

[Carl Wilson]

The gearbox is essentially finished now. I installed the worm shaft yesterday.

First the bearing was pressed onto the keyed end of the shaft and the worm slipped over the splines.

Then the worm shaft was inserted into the gearbox and the bearing driven in to the approximate final position.

This allowed the bearing for the opposite end of the shaft to be simultaneously driven into the casting and over the shaft.

All the caps and retaining plates could then be fitted. Each 6-32 UNC countersunk fixing screw got a dot of Loctite 222.

I then fitted the sight glass, oil filling 1/4 BSP plug and change wheels. I still have to make a retaining nut for one of them.

Gasket made for the bottom cover to be fitted.

Bottom cover 3/8 BSP drain plug fitted and ready to go on. The 10-24 UNC securing screws were wet assembled with Loctite 222.

To fit the Gryphon motor I should have prepositioned this 1/4 UNC cap screw prior to fitting the leadscrew end cap. Of course, I didn't. So to get it through the peripheral slot in the cap I cheated and filed flats on the head.

The motor was then fitted using the 1/4 UNC cap head screws as removed. These were Loctited too.

All that remains is to fit the change wheel cover. I'm currently painting it so it should be on in a day or so. The gearbox has been boxed up ready for refit to the machine at a later date.

 

[Carl Wilson]

I got the table apart...more to come.

 

[Carl Wilson]

I'm just back in from a frankly horrible, filthy evening in the workshop. As you saw from the last post, I have separated the table from the cross slide assembly. I started stripping and assessing the latter this evening.

The cross slide was incredibly dirty with decades worth of accumulated grease, swarf and debris.

I first took off the cross slide lead screw, the threads of which are in a generally good condition.

Here is the table lock. As the next picture shows, this has been bent at some point. Presumably from overtightening.

I should be able to make a new one. Next I disassembled the gib arrangement.

The small balls that can be seen here engage in recesses in the gib strip. Then grub screws (previously removed) bear perpendicularly on the balls and when tightened force the balls against the gib, thereby tightening it.

These grub screws bear against springs thst preload the cover plate. This fits on the bottom of the cross slide, with a slot for the leadscrew nut. It's task is to prevent swarf ingress into the knee mechanism. You'll recall I accidentally bent the cover plate when I removed the table assembly from the knee.

I spent some time blasting grease from the lubrication drillings using the blow gun. After this I dunked the cross slide into a bath of equipment cleaner.

This picture was taken after the solvent bath. More thorough cleaning will be required, but the unit is now much easier to inspect and work on. Some of the lubrication drillings can be seen here, like those in the vee way on the left hand side. The large central bore is where the leadscrew nut fits. This has an oil delivery channel which is fed from another drilling.

Below the leadscrew bore is another hole revealed after removing a top hat shaped plug. Inside here are oil drillings for the table vee way.

There are a number of BSPT plugs and grub screws that close out lubrication ports. I've removed all of these to facilitate the chasing out of all the grease.

There is some scoring to the ways, of which this is typical. I'm no expert in these matters but I think there is still sufficient bearing area all around this site. Here is a close up view.

This scoring seems to be isolated to the flat ways. As I've said before I have neither the tools for or experience of scraping in ways, so it is what it is.

These oil nipples are damaged and they have so far refused to yield to any attempt at removal. They are absolutely solid and I think I will have to resort to cutting them flush and then drilling them out.

 

[Carl Wilson]

Plan for the above today is to heat the nipples with the heat gun to try to break any compound out. Loctite goes at about 76 Celsius if memory serves.

 

[Carl Wilson]

Well the heat didn't work. I made a fundamental cognitive error, which I will explain shortly.

After trying the heat gun I decided to get serious and I cut the heads off the nipples. Judging by a nipple removed from elsewhere on the machine and the size of the offending items, I made an educated guess that a 6mm drill would basically take the core right out of them.

Thereby having removed any hold the threads might have, I could just go in with an easy out.

It worked, but not quite how I supposed.

Once I'd drilled down about 6mm I tried the easy out. Bingo, it turned. And turned, then turned some more. I pulled it and the nipple came out. Of course, the nipples were push in.

Now, there are literally thousands of push in lubrication nipples on machine tools the length and breadth of the UK. However, because these looked like grease nipples, and because there are threaded ones elsewhere on the machine, I made an assumption. A foolish one as it turns out!

They are all out now. Those of you who remember my Lathe VFD and DRO threads will be pleased to see that the CT90 photo bomb is back.

I want to replace all the nipples on the machine with fittings so I can have centralised lubrication, ie one shot. I'm assuming these below are pressed in too. I can get no purchase on them. I'm going to let sleeping dogs lie. It'll do my wrist good to pump some oil into them every so often.

 

[Carl Wilson]

This evening I machined my knurling tool down to fit in my Dickson tool holders. The shank was a shade over 19mm so I took it down to 16mm.

Assembled and in the tool holder now. Hopefully will get the special retaining nut made for the gearbox change wheels tomorrow.

 

[Carl Wilson]

I have ordered a clamp type knurling tool. My Harrison M250 doesn't seem to have the grunt for this one.

That's in freecutting steel. It's not very good and I can't really exert any more force on the tool without, I fear, breaking something.

 

[ronan]

I think knurls put huge stress on the crossfeed leadscrew and nut, as you are not cutting metal but deforming it. Thankfully i have never had to do much of it.

 

[Carl Wilson]

Yes they do that. I'd forgotten how brutal it can be.

I'm actively looking to redesign the change wheel retaining nuts and make two new ones, to do away with the need for knurling.

 

[Seadog]

A clamp or scissor type knurling tool removes all of the strain on the screw. Plus you can get a lot more effort into the knurl for tough material.

 

[Carl Wilson]

Yes. Hopefully it will do the job. Clamp type knurler arrives tomorrow so will give it a shot.