Harrison M350 Rebuild

  1. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    A good while ago I decided that I needed a bigger lathe ( I already had a Harrison M300), and stumbled upon this M350 at a decent price. After going to look at it, I knew the bed was worn out, there was some noise from the headstock, but not too bad I thought, and the rotary speed selector seemed to be doing random things. No big deal, I thought. So I bought it. Here it is when I went to collect it. The eagle eyed among us will notice that the cross slide hand wheel is not the correct one.

    Buying.jpeg

    The seller had arranged to get it loaded onto my trailer, then I headed up the road back to sunny Scotland.

    Transport.jpeg

    Once home I had to leave it outside overnight on the trailer, so lashed it all with WD40 and went to bed as it was gone 11pm. The next day I used this almighty engine hoist to get the lathe off the trailer. It's a bloody beast of a thing and a bit cumbersome but I'm glad I had it.

    Unloaded.jpeg

    My neighbour appeared and gave me a hand get it inside and into it's final resting place.

    Home.jpeg
     
  2. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    After having a think about the best way to get the machine up to a good standard again, I decided that I would have the sliding surfaces reground & built up with Turcite where required. Also, a full strip-down and inspection of the mechanical parts would be the order of the day, replacing or repairing parts where required. The main reason I decided to do this was to find out why the headstock was noisy, and why the speed selector didn't work as it should. So I started ripping it apart.

    Stripdown2.jpeg

    Stripdown1.jpeg
     
    eLuSiVeMiTe likes this.
  3. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    The reason the speed selector didnt work correctly, and probably why the cross slide hand wheel is off a different machine is because it appears the machine has fallen onto it's front at some point, or some goon has battered it with a forklift or something. I also noticed that the carriage hand wheel has a nice weld repair on it too!!

    Here is the speed selector on the headstock. The inner part with the arrows should move with the centre knob to indicate the speed selected.

    Selector1.JPG

    After some more stripping it became more apparent that something has hit the machine as the speed selector shaft is bent and a circlip has been pushed along the shaft.

    Selector Shaft.JPG

    This a fancy mechanism, where you have one shaft going through the middle of the other, to operate all of the headstock gear selectors from 2 concentrically mounted controls, and along with the shaft being bent, a couple of the gears inside were knackered too. These are obsolete from 600 Group, as I found to be the case with a lot of parts for the machine, however they did supply me with the drawings for the damaged parts to allow me to have them made. The good man that is @Pete. on this forum very kindly knocked up some new ones for me. Unfortunately I cant find any pictures of the gears at the minute but I'll add them if I do find them again.
     
  4. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    Once all the bigger bits were stripped off I dismantled the headstock. It's a pump lubricated affair, so basically the oil is pumped from a tank below the change gears into the top of the headstock and is distributed through a manifold to the areas that require oil. This manifold is at the top of the headstock so with that removed I set about removing the speed selector mechanism. After that all the gears and shafts were stripped, working from the top inwards as that is the easiest way to get access.

    Headstock2.jpeg

    Here is the selector mechanism on the bench along with some other headstock internals. I'm sure I'll remember how it goes back together! Just to the top right of the photo you can see the forward/reverse selector fork, it's brass and unfortunately is quite worn. You can see the heat marking in the paint - another obsolete part.

    Headstock1.jpeg

    The main spindle bearings are rough, the front one as seen below has plenty scoring on the rollers. The races aren't too good either.

    Headstockbrg2.JPG

    Quite a few of the bearings on the other shafts were shot, but more so on the forward clutch pack bearings, again you can see the heat marking on the clutch body in the photo below, compared to the reverse clutch pack next to it. The bearings were very black and in some cases difficult to rotate by hand.

    Clutch1.JPG
     
    slim_boy_fat and eLuSiVeMiTe like this.
  5. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    Once the headstock was empty the priority became getting everything ready to go to Brian at Slideway Services in Nuneaton for a full regrind. This enatails getting the bed off the stand and cleaning all of the P38 body filler type compound Harrison use to set the machines on when assembling them to the stand, and generally getting things cleaned up.

    Here is the bed coming off the stand.

    Bed7.jpeg

    A selection of the other parts that need to go away with the bed

    Grinding1.jpeg

    A little mystery presented itself when I was checking over the tailstock. The spec for the M350 tailstock is MT4 and a quill diameter of 63mm, but upon checking what I had, the taper was MT5 and a quill diameter of 73mm. I decided to call the people at 600 Group to pick their brains and at first they were baffled, and the first thought was it had been mucked around with and someone had fitted a tailstock from a different machine. That would have just been typical really, going by the previous accident damage that had been discovered. Anyway, I sat myself down and asked if it would be possible to buy a new complete tailstock, and what would the price be for such a thing? Thankfully this was another obsolete part so no price was mentioned except that it would have been ridiculously expensive. A couple of days passed by, and a lady in the parts department at 600 Group called me, and told me that they had gotten to the bottom of my tailstock mystery. It would appear that for the most part these lathes were built with a tailstock using a quill of 63mm and MT4 taper, however for a very short period in 1989, they supplied the M350 with a tailstock using a 73mm quill and MT5 taper. She then went on to tell that because they were so rare, and because they were clearing out the stores, I could have a brand new quill to suit my machine for £200, quite a reduction on the standard price of these things! The main reason I was looking at the quill in the first place is because it was quite a loose fit in the bore, and the taper was quite scabby too. Anyway I gladly took her up on the offer of the new quill and it arrived a day later.

    Old & new.

    Tailstock Quill.jpeg
     
    phm87, slim_boy_fat, R-D-R and 3 others like this.
  6. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    I got the sliding parts away to Slideway Services (unfortunately no longer in business) then got the stand away to a local shot blasters to be blasted and primed.

    Stand2.JPG

    I was told that the original Harrison colours were RAL6014 Yellow Olive for the bottom of the stand/base and BS384 Light Straw for the rest so I got these colours in aerosol from Smith and Allan, in their Tractol 329 machinery enamel. Once the stand was in place I lashed the paint about it.

    Stand1.JPG
     
    slim_boy_fat, R-D-R and eLuSiVeMiTe like this.
  7. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    slim_boy_fat and eLuSiVeMiTe like this.
  8. Carl Wilson Member

    Messages:
    1,414
    Location:
    Moray
    Superb work, really like seeing machines being rebuilt to such an excellent standard.
     
  9. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    Thanks Carl. Hopefully it all works as it should once complete. I started this rebuild a while ago but just thought I'd get a thread going to document it. Just trawling through all of my photos to find relevant ones to add to the thread.
     
    Milkybars likes this.
  10. Carl Wilson Member

    Messages:
    1,414
    Location:
    Moray
    Hi Scott. I'm sure it will all work perfectly. I got my Harrison Mill about a year ago but am only now starting the restoration in earnest. It's had to wait while I finished my M250 lathe and other jobs.

    I'm really enjoying reading about your project and I'm going to learn a lot from it. So thanks!
     
    scottmk1 likes this.
  11. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    While the big bits were away being reground I tackled the overhaul of the apron. I stripped the whole lot to a bare casting, cleaned it all out then rebuilt it with new bushes, bearings and seals throughout.

    It wasn't too tricky a job, apart from the power feed engagement mechanism which feature an over centre cam type arrangement to latch into the 'on' position. To get all that together inside the partially assembled apron casting required 3 small child size hands, which I don't have. A lot of perseverance & swearing soon had it all back together, and I'll be glad if I never have to take it apart again.

    Here is the pile of bit's on my bench. The two brass bushes are 600 Group only parts, and were quite worn so I had to give them some of my money for new ones. Thankfully they were on the shelve & not yet obsolete. Whilst in amongst it all I decided there was no better time to replace the half nuts as well, again these were on the shelf. Strangely, when I gave the machines serial number to 600 Group spares dept they were adamant that this machine left their premises as an imperial machine, yet everything on it is metric. This was confirmed by most parts that can be interchanged between metric & imperial having an 'M' stamped into them.

    Apron3.jpeg

    New bushes from 600 Group

    Apron Bush.JPG

    Semi rebuilt apron - with that power feed engagement mechanism back in!!

    Apron1.jpeg

    Here is the apron with the rest of it's innards refitted. All nice & tight, just as it should be.
    Apron2.jpeg

    You can see some parts have been stained & pitted by coolant ingress. Thankfully this was 99% limited to parts that are not going to be affected by it & I had to clean up a couple of gear teeth here and there but it could have been a lot worse.
     
    Last edited: Aug 3, 2019
    slim_boy_fat, R-D-R and eLuSiVeMiTe like this.
  12. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    Next up to get the treatment is the feed gearbox. The outputs to the lead screw and power feed drive shaft both had a bit of wobble in them, and the innards were filthy. Another area of these machine prone to coolant ingress, thankfully nothing was too badly corroded.

    Feed Gearbox5.jpg

    Again this was stripped to the bare casting, in order to check everything over and repair or replace items where required. Each end of the casting has a bore that you can remove the shafts through & in most cases house a bearing, these are sealed up with a plain slug of steel with an o-ring around it's circumference & on the upper shaft you can't get to it from the inside to knock it out, and there is nothing on the outside to get hold of. My solution was to drill & tap the slug M12 to jack it out. This didn't work very well, as the shaft is hollow so the bolt had nothing to push against. I didn't have a 14mm drill bit so used a slot drill to open up the hole, them tapped it M16, this time it worked and I got that slug out.

    Feed Gearbox6.jpeg

    I pulled out the shafts and gears, and was left with the 3 selector forks and the fandangled rotary selector mechanism, very similar to that in the headstock.

    Feed Gearbox4.JPG

    In this photo you can see how the gear selectors stay in place. The selector fork arm has 3 holes drilled in it, which a spring loaded ball detent presses against. When you move the knob the spring is compressed until it reaches the next hole, and then the ball is pushed into the hole, giving the feeling of it latching into place. The spring tension can be adjusted as the detent units are threaded on the outside, so all you have to do is give them a little bit of a turn and see how it feels. This can be done from the outside so no need to open up the gearbox. Here is the sort of thing I mean.

    Ball Detent.jpg
     
    slim_boy_fat, skotl, galooph and 2 others like this.
  13. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    The feed gearbox was put back together with all new bearings, bushes and seals, along with a new output drive for the lead screw. You can clearly see the wear on the old part. More money in the pocket of 600 Group.

    Lead screw drive.JPG

    So, I got the feed gearbox all back together and all seems good so that was put aside with a rag over it for the time being. Unfortunately I don't have any photo's of this as my phone didn't back them up, and I subsequently lost that phone & the photos on it (along with my trainers!!!) on a night out in Haarlem in the Netherlands.

    I'd had a call from Brian at Slideway Services at this point, to say everything was ready for me to collect. Here is a list of work he carried out for me:
    Regrind bed, saddle, cross slide & compound slide. It was very worn so the underside of the saddle was built up with Turcite, as were the gibs, to bring everything back to factory spec. The headstock was also checked for alignment with the ways, it was lightly scraped in to get the alignment bang on.
    The most interesting part was the tailstock. As I previously mentioned I got a new quill for the tailstock, however the bore in the tailstock casting was worn beyond being a good fit with new quill. The solution here is to coat the new tailstock quill in hard chrome, then hone the bore of the tailstock casting until it fits. It's a very very close sliding fit, and I've never seen anything quite so tight a fit yet free to move. Well not on anything suitable for this forum.

    Once I got the parts back from Brian I set about painting them. In hindsight I wonder if I should have done the painting first, but it was too late for that. You might have gathered by now that this machine had a few hours under it's belt and wasn't in the best of shape - mechanically and cosmetically. So I set about the non machined surfaces with a needle gun to remove the remains of the filler material that they use to smooth out the cast surfaces. I was going to redo the filler material, and make it all nice again but that really isn't my thing. So I didn't bother.

    Here it is getting the good news from the needle gun:

    Bed3.JPG

    Bed4.JPG

    Once I had all the filler off, I gave it a good going over with some scotchbrite, then a coat of quick drying zinc primer. This was followed by a couple of coats of white primer/undercoat (tractol 816 I think) then the BS384 Light Straw top coat.

    Bed6.JPG

    As you can see I did the are in between the ways in the same colour as the rest, as I just couldn't be arsed to paint it red, I done that on my M300 and it was such a chore - bring on the oily bits!
     
    slim_boy_fat, R-D-R and eLuSiVeMiTe like this.
  14. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    With the stand and bed painted, it was time to mate them back together. First off I got the base where I wanted in my workshop, I also made a cople of frames to go under the base to raise it by 50mm to suit me height better so got these bolted on too. With the base in it's final resting place, the next thing to do is get some P38 body filler. The bed sits on top of 4 small metal plates, one in between each pair of holding down bolts. The idea is that these should all be a snug fit - that way you know the bed is not twisting to match the shape of the base, so with these 4 small pads in place, you set the lathe bed, onto a bed of P38 at each end. When you lower it into the P38 the 4 pads take the weight, and the excess P38 squishes out, the excess is removed before it goes off. Once its set you have a foundation for the lathe bed that covers the whole footprint, rather than just those 4 pads. After the P38 has gone off you can nip up the holding down bolts, but dont be heaving on them, it really is only a nip up they need.

    Getting ready for the filler:

    Bed5.JPG

    After the filler has set:

    Bed2.JPG

    I used M16 stud bar as guides to keep everything aligned when I set the bed down onto the P38:

    Bed1.JPG

    After this I removed that stud bar, and fitted the correct holding bolts. I decided the feed gearbox should be reunited with it's rightful keeper, so got it outside for a coat of paint:

    Feed Gearbox1.JPG
     
  15. Dieselkid 63

    Dieselkid 63 Banned from forklifts

    Messages:
    4,253
    Location:
    Wellington, New Zealand
    It is a complete pain to paint between the bedways, you’re right! Sort of need a bent paintbrush to do it. Looks smashing so far!
     
    scottmk1 likes this.
  16. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    The next day the paint was dry on the feed gearbox, so I knocked up a gasket for it, and fitted it to the lathe bed, I also cleaned up and refitted the rack for the carriage. Once that was done I sanded the areas where the P38 was applied ready for a coat of primer and paint.

    Feed Gearbox Fitted.JPG

    So the next step was to fit the legend plate, selector knobs and rotary knob to the feed gearbox. I also lobbed the tailstock on the bed and the end bracket for the lead screw & drive shaft, and painted the sanded areas.

    Bed7.JPG

    And that's how it stands at the minute. I've got the gap piece painted ready to go on, and the motor has been rebuilt with new bearings and a lick of of paint. Next up will be the carriage/apron/cross slide assemble, along with the headstock. I'm going to try and get plenty more photo's of it along the way and keep this thread upadated as I progress.
     
  17. scottmk1

    scottmk1 Forum Supporter

    Messages:
    1,101
    Location:
    Scotland
    Yes it's a pain, and when I done the M300 it took ages, and I was sick of it. On this one I decided that I wouldn't bother even though there is much more space to get a hand in there.
     
  18. Dieselkid 63

    Dieselkid 63 Banned from forklifts

    Messages:
    4,253
    Location:
    Wellington, New Zealand
    On the Bantam it’s easier to go in from underneath to get the stuff closest to the bed... lucky you having a sandblaster! They were difficult to clean by hand, to say the least!
     
  19. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    9,583
    Location:
    Bedfordshire England
  20. Dieselkid 63

    Dieselkid 63 Banned from forklifts

    Messages:
    4,253
    Location:
    Wellington, New Zealand
Advertisements