Harrison Mill Refurb Part 5 - Threading Woes and a Look at Past Progress
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- Опубликовано: 8 сен 2024
- Hello everyone. In this film we look at my abortive attempt to generate a 5 acme test nut for the mill - stymied by a schoolboy error on my part. And we look at some earlier progress I made with the mill refurbishment.
You can read about my earlier mill refurb work here:-www.mig-weldin...
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Hello people! Thank you so much to everyone for the very positive response I've had so far to this film. I almost didn't put it out, it didn't seem worth it to show a cock up! This channel isn't a vanity project though. I do my best to be as accurate as possible in the home shop, but I make mistakes and learn from them. So if I do cock up, I will show it. If you are interested to see what went on with the motor, gearbox and other mill components before I had this channel, please have a look at my thread on the mig welding forum, here:-
www.mig-welding.co.uk/forum/threads/harrison-horizontal-vertical-mill-restoration.82648/
Hi Carl, the benefits of a trial part, now there's a valuable 're-learnt' lesson for me in 2022! That thread form looks absolutely cracking, if you get that finish in the bronze you will be over the moon I am sure. Safe travels. Cheers, Jon
Thank you so much Jon. I am as sure as I can be that the thread in the bronze will be good. I really appreciate your comments and your support. Thanks for the good wishes.
Such a beautiful job on those knurled nuts.
Cheers, Peter.
Thank you very much Peter.
Nothing is a mistake when you learn from it, there's a lesson there for all of us. Lovely refurb work on the gearbox. The casting quality in those older British machines is so good. Puts my Chinese copy of a Taiwanese Myford to shame! Best wishes, Dean.
Thanks for that. Yes I agree totally. The whole point of the delrin test nut was to develop the process to a point where I am confident to apply it to the bronze. You are right about the quality, the whole machine is built to a standard not to a price. Thanks for watching and commenting.
Thank You for the education. I would have liked to have seen what you did exactly what you did to those motors. I have no training at that. I sure like what you do. Thanks Ron 😊
Hello Ron, thank you very much for your comments and for watching. If you look at the pages I have on the mig welding forum you can see pictures of how I rewired the motors. The link to that site is in the description. Thanks very much for your support, it really means a lot. I hope you enjoy my other films. Please stay tuned as there are plenty more to come!
Great video Carl, glad the channel is growing.
Thanks Rob, really glad you enjoyed it. If I am honest I was in two minds about putting it out. Seemed rather disjointed. Glad I did though and glad you enjoyed it. Thank you for your continued support. It genuinely means a lot.
Pity about the Acme threading woes, but a good and thankfully not too expensive lesson, thanks to the foresight to manufacture the Delron test nut. I appreciate you explaining the feed-gearbox workings using the exploded drawing, prior to you showing us the now painted and completed gearbox, it provided me a much better understanding of its inner workings. Already looking forward to the next instalment of the mill refurbishment.
I always like to have a trial run, in any machining operation. If you would like to see more about the feed gearbox, have a look at my posts on the mig welding forum. I have put a link to them in the description. Thank you very much for watching and commenting!
@@carlwilson1772 Yes, you can leave the change gears as they are, and use the VFD to do speed. Just swap them around, as most VFD drives and motors will easily go up to 200RPM with minimal loss of torque, though probably best to keep it below 120Hz anyway for noise and heating, and at the low end you drop off a cliff torque wise under around 30Hz, so best to keep in those ranges. The little motors do well at higher speed, I have gotten them to close to 400Hz, though you need to ramp up slowly to that so they do not loose lock, and at that they are not going to put out much power simply because the current is so low.
VFD put in around 1 second ramp up time, though set up the ramp down as fast as possible for things like limit switches, and DC braking hard and heavy, with around 5 seconds of it. Had a motor drive for a packing machine that took a 1kW motor and wound it up to 120Hz in 5 cycles, ran it for 35 cycles, then slammed it to stop in 2, basically as hard as the VFD could do it without needing an external chopper. 2kW inverter to get that extra drive margin and bigger DC bus capacitors, and the inverter ran cool, not so much the motor. But not as hot as the single phase motor next to it, that just ran a belt, with practically no load. Single phase small motors are bloody inefficient power wise, running at 100C case, and no way short of making it 3 phase to run cooler on the 1/2 HP motor.
@@SeanBZA Thanks Sean, a lot of really good info, I can definitely gain from that. Thanks for taking the time to watch and to comment.
@@carlwilson1772 Already followed the link :) Enjoying your content
@@paulhammond7489 Thank you Paul. I really appreciate your support.
Hello Carl,
As always a very informative video... Once you have the correct change wheel I feel sure the thread cutting will be just fine. The one you showed although technically wrong, looked great. Keep up the good work.
Take care.
Paul,,
Thank you so much Paul. Yes, it was a cracking thread, shame it didn't fit! The whole point of the delrin was to work out all the Gremlins before committing to the bronze. I'm glad you enjoyed it, thanks so much for your support. It means a lot.
Great video again Carl.........I enjoyed that. There wouldn't be a machinist in the world that hasn't felt your pain with an incorrect pitch cut. Reall y enjoyed the description of the Mill gearbox and the pictures help a lot. Have a safe hitch and hope you're home for Xmas.
Thanks Tony much appreciated. I'd like to say I won't make that mistake again but I probably will! Thank you for your support mate.
Always happy to support smaller channels... seems like the big boys get too far ahead of the rest of us ! 🙄😂
Sub & a like , mate... 🤗
ML7 is the lathe & a monster of a Van Norman (can't remember the model) is the mill here...
We're livin the dream !! 😂
From the Emerald Isle
😎👍☘️🍺
Thanks very much! I have subscribed to you now too.
Lots of good info in there for me Carl thanks. Interesting to see the feed motor and nut arrangements, very different from mine which has the swivel table. Cheers.
Yes, two very different set ups. I believe that on the universal model the feed gearbox also has an internal dog clutch to disengage the drive. I'm glad you found the film interesting. Thanks very much for watching and commenting!
@@carlwilson1772 yes it does Carl. Cheers
I know it wasn’t your issue but it does seem an oversight that Harrison didn’t mark the tooth count on the M250 change gears. It can be difficult to check the pitch with a scratch pass on an internal thread. What I sometimes do is check the set up on a scrap of round stock running the internal threading tool on the backside of the stock with the lathe in reverse with the feed direction set accordingly.. I too am a fan of Paragon paint. On larger items I use a mini paint roller designed for gloss as it’s quicker and leaves a consistent finish not too dissimilar to spray but without brush marks.. Enjoying your channel thanks to Haxby Shed.
Thanks for watching Tony! It was my issue unfortunately! Harrison do mark their gears. The supposed 63t was one I adapted, please have a look at my earlier video on this. The gear I bought was meant to be 63t but it seems the supplier sent a 60t in error. Anyway the error was mine because I didn't check. I adapted that gear to replace a damaged 3d printed 63t. Thanks again for your support.
Fan simpler to do what I did, and use a mains fan, with an adaptor plate, to give the motor forced air cooling. 120mm square fan provides enough cooling air, and running all the time is going to make sure the motor runs cool at all times, as a non VFD motor running off a VFD tends to run hotter under all conditions, so extra air is better. Remove internal fan, though the one cast into the rotor can stay. Power on fan with the machine power, not with motor run, so it can cool down the motor between use.
Thanks for the tip my friend. I will bear that in mind. Thank you for watching and commenting.
The Horizontal model has such a neat powerfeed on it in comparison to the Universal. I mean it wouldn't have worked with the swivel table of the Universal so I understand why they have it hanging out at the end of the table but it's still much neater!
Yes I totally agree, it is neat. The universal has a recirculating ball screw too instead of acme, I believe. Thanks for your support my friend.
@@carlwilson1772 mine has a ball screw but it was an option not fitted to all of them.
Has it's upsides and downsides vs ACME. Better for "production" work where you're using the powerfeed, worse if you're doing manual as it will "back drive" easier and you *have* to be militant about locking the X axis when not using it otherwise it'll wander!
@@fastdruid Great info my friend. Have a look at the channel Haxby Shed. He has a universal machine with ball screw. He has been watching my films to get info. I am sure he would appreciate your experience and I think you would like his content.
Great video Carl and an excellent explanation of the trig error and how to solve it, many thanks. I too subscribe to Haxby Shed and it was interesting to see that Paul referenced your channel for info on the Mill, along with Ralfy Customs - you guys are about the only source of videos on the Harrison Mill that I've found and will be extremely useful for when I start on the refurbishment of my mill. My mill doesn't have the swivel table like Paul's but I do have the vertical head. The only thing I wish is that it would be nice if the head had a quill feed. My mill is an ex-college machine and doesn't appear to have had much use, it's in generally good order but it's missing the coolant pump and during the delivery transport some muppet lifted it using the table wheel - in the process they managed to break off the "speed" handle which I'll have to remake, more annoyingly they managed to bend the table lead screw, not badly but enough to notice and it's annoying. Any good tips of how to possibly straighten the lead screw? I believe it's only the section close to the handle, when turning the handle you can observe that the scale appears to have a slight wobble, caused by the bend in the shaft. Other than that, I have a slight oil leak from the vertical head, it appears to be coming from between the head and the flange on the column. Oh and I dashed into the workshop to check if I had the change gear retainers still in place, they are there - your replicas are excellent and look exactly like my originals! (PS I didn't know the change gears were Myford, very good to know that).
Thank you Jason. I really appreciate you watching and commenting. I'm glad you enjoy what I call the "Whiteboard sections". I really struggled with maths at school. But it all made sense for me when I began my engineering education. When I started this channel I hoped that bringing in the principles behind the practice - one of my favourite subjects - would be my "USP". I think only Joe Pie does similar. So I am really glad you like it!
I have the vertical head for my machine and the horizontal overarm too. I hope you get a chance to look at my other films and check out my writings on the mig welding forum for more info on the mill. There is a lot of room in the coolant sump to fit a replacement pump. I feel your pain re the table leadscrew handle. My machine fell over in the delivery lorry and broke the handle too. Regarding straightening the screw, I think I'd mount it between centres and clock it to see where and how much the deformation is. Then you will know how much of a bend to apply to straighten it.
Mine is ex college too but has been roundly abused. You are right about the lack of a quill.
There were three models of Harrison milling machine, Horizontal (no swivel), Universal (with the swivel) and Vertical. There was the option of the vertical head on both the Horizontal and Universal models.
My Harrison also had a bent Y screw. I straightened it by clocking it between centres in the lathe and carefully pushing it straight.
The heads aren't the most oil tight at the best of times, they do weep a bit. There is however an O-ring in there that has probably died.
If you're on Facebook there is a group specifically for Harrison Milling machine owners....there is a manual in there too.
@@fastdruid Great info mate thanks!
@@carlwilson1772 I think you're right about the Whiteboard sections - I too struggled with maths to an extent but oddly now, it makes much more sense to me that it ever did at school, I use maths every time I'm in the workshop! thanks for the tip on the shaft, between centres and clock it is the way to go I think. I've been watching some of your other videos and I'm also on the MW forum, been reading your thread today.
@@coplandjason Thanks Jason, really pleased you enjoy the theory bits. I'm glad you are getting something from the videos and the forum posts. I plan on many more films about the mill and other projects, your feedback and support really spurs me on. Good luck with straightening your lead screw!
Lovely work on the motor, you do however make me feel a little guilty about just throwing away the original motor from mine and buying a brand new one...
It is an utter pain in the a*** to get to the bearings on the motor with where they put it though, I'm not entirely surprised no one ever bothered!
Thanks for your support mate! Yes you are right, I said on the mig welding forum that the plastic caps were still on the grease nipples. They always get lost, so it's likely no one ever greased the motor bearings in 50 odd years.
Excellent video. It's great to see other people make the same mistakes as me. Sorry to bother hear about the gear counting issue. Have you thought of 3d printing a gear for the one off operation? I have designed gears on an online site and printed them. They work great for the time I needed them. Great job.
I just watched the other video with the gear description and failure. I have also made a gear hob and cut needed gears . The hob I made still requires the blank to be indexed as the cutter is not a spiral but strait teeth.
Thank you very much. Sounds like you have done excellent work. I managed to buy a 3d printed 63t 1.5 mod gear designed for Harrison M-series lathes. I'm at work at the moment but when I return I will be back in the game.
Well I made it.
Where on earth have you been?! I was getting worried!!
@@carlwilson1772 you put it out at 1 Am here LOL.
@@cainbeeping8480 Yes, I didn't do it on purpose! I usually end up posting late at night so my few US viewers get to see the films first.