Benchtop Mill High Low Gear Replacement | How To
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- เผยแพร่เมื่อ 20 ต.ค. 2024
- How to replace the nylon high low gear on an MH28 mill, also applicable to similar benchtop mills BF20 and G0704 with high low gears located in head casting.
My method uses a makeshift press made from workshop scrap to press the high low gear shaft out avoiding damage to the bearings.
Thank you! this is very helpful
Interesting approach with the makeshift press! I had the same fate with my slightly smaller Bernardo KF 25 Pro around the same time you replaced the gear. In lack of any professional equipment for bearing installation, i unfortunately just hammered them in. :-/
BTW: The stripped gear teeth show that the gears don't mesh properly, i.e., they don't use their full width. This also was the case when I stripped mine, and I learned to be careful with the position of the shift knob.
Good to see a video on machine repair. The few times I have had to do work like this it is a bit of self discovery as the drawings are usually poor quality. Great series on the loco build too.
Thanks Grant, hopefully it might help some out that gets in the same situation I have been in scratching my head how it’s even possible to do this.
Thanks 🙏 helped me
Nice video! Would you happen to know if your instructions apply to an OPTIMUM BF47 Vario?
Thanks, not sure but likely so as seems to be similar setup for most of their mills.
Great video!
I have an Optimums BF46 Vario and suspect I have a gear problem in that I hear rough noise at higher speeds. No noise at below 1000 rpm. I suspect that my machine is similar and your video is applicable. Your thoughts and recommendations? May I ask where you purchase new gears? Also I wonder if you can 3D print replacement gears out of a similarly durable material. Can you please tell me what you believe the gears are made of? I have a 3D printer and CAD software as well as a CNC mill and may give it a go. Thanks
Thinking of buying the very same mill. My only problem is $50 every time you strip the gear. i'm new to the hobby so i guess i'll bust them for sure. My question is how easy do they strip under normal use.
Hi Steve, in my experience I have been doing something wrong or beyond it’s capability to have it happen. Examples, 50mm face mill with reasonable depth of cut and stalling the cutter or the machine jumping out of gear (this can be avoided by tightening the selector if it comes lose). In my case with very regular use it’s happened about once a year. They are a good mill and a lot of the similar sized machines have the same setup. They are there to protect more expensive parts. As for cost, they are probably the cheapest part of owning a mill with the tooling being top of the expenses.
Excellent video! Thanks much! I have an Optimum BF 46 Vario and may need to replace the gears as well. I get a rough noise at higher speeds. Do you think this is the problem? I assume the same gear setup is used in my machine.
Two questions:
1) where do you purchase your gears?
2) would it be possible to fabricate the gears out of a steel alloy for more durability or do you think there is a reason for plastic gearing which I assume is what the machine comes with (I haven’t opened my system up yet.
Thanks, the rough noise can be it starting to wear, when it actually fails the spindle doesn’t turn when the machine is running. You can check through the access panel in the back of the head if it’s failing. I’m not sure what the gear setup is in the BF46 as it has 3 gears rather than 2 but a lot of the machines share a similar design. I got the replacement gear from the machine supplier which is machinery house here in NZ. There is also another plastic gear that the motor drives on mine, which is meant to fail first but never has. I think the reason for the plastic gear is so if it slips out of gear it doesn’t take out the gear on the spindle that would be even harder to fix. I have considered making a brass one, even bought the gear cutter for it, if you were going to make one it would need to be made in a couple of parts then welded together. The gear is made out of some flash nylon material so don’t think anything 3d printed would cut it. Hope this helps, good luck.
@@SS-Workshop Thank you so much for your reply! I would like to add a Digital Readout (DRO) and would like to ask if you have any recommendations on the type and brand to purchase and methods and locations to attach to the machine. Good luck with your projects! Cheers!
@@neatmachine not sure if you have seen this video but shows how my DRO is installed on my machine th-cam.com/video/IhoZlG0Rj64/w-d-xo.html . My DRO is a Chinese clone of the Sino which I ordered through AliExpress. You do roll the dice buying through them so if you can get an ok price locally it’s probably the better move. The glass scale ones are the best but have previously used the magnetic scales with the individual displays on a previous machine but you miss the functionality of a proper DRO the can do bolt hole layouts and all the other features that come standard on a proper DRO. Hope this helps, if the video doesn’t show enough let me know, happy to answer any other questions you have. Cheers.
Mate, this video is amazing. I'm looking to get one of these mills and this has given me a great deal of info the internals of the head. Thanks!
Have you considered machining the two internal gears out of steel and leaving the sacrificial nylon one on top?
Thanks, great to hear. I have considered steel and brass as options and actually picked up the gear cutter to make one. The main consideration is that on at least a couple of occasions when it has failed the machine had jumped out of gear and if that happened with a more solid gear it would take out the steel gear on the spindle which is even harder to replace. A common CNC upgrade is to drive the spindle directly with a belt drive so that’s another option but would change the speed and disable the quill action so may be not. This is one of those things where when it happens it’s top of the list then it’s replaced and it’s back to the bottom of the list, given I may have it happen once a year with regular use and it’s usually something I shouldn’t have done, keeping a spare isn’t a bad option.
@@SS-Workshop how do you find the HM32v besides this gear issue. Started watching your videos and must thank you for the tips. I recently bought same machine.
@@MacGyver3446 mine is the MH28v but think it’s similar. I have found it to be great, really well built and very capable. I have pushed pretty hard with a carbide insert face mill and it has handled that well. The only thing it doesn’t do is run as slowly as I would like for using the boring head and because of the variable speed it lacks torque at low speed which it where it would be useful.
@@SS-Workshopsorry I made typo. I was going to buy the MH32 and so was fresh in my mind, I bought the Mh28v but still have to add the digital bits. I am not by any means a professional machinist but do have the knowledge and basic know how. I watched your videos and enjoy and appreciate the knowledge you share. I buy from Hare and Forbes and bought a vice today and took your advice by going bit bigger and removed the turn table at the bottom. Those wheels you made, then sand blasting to make look like casting is amazing. I hope to get to that level one day to make finer things for my hobbies.
@@MacGyver3446 congratulations on your purchase. I don’t come from a machinist background either just trial and error in the home workshop. I just started out cutting the odd slots and squaring up blocks and it all started from there. The locomotive project being a great excuse to use more exotic materials and try some new techniques. Sometimes I even surprise myself with how things turn out and the wheels were certainly one of those. Good luck.
Where can i find replacement gears in metal?
I haven’t found any for my mill yet the only ones I’ve seen are for the Sieg machines from little machine shop. I have purchased the involuted gear cutters to make one, still working on what material as it would be nice not to take out the gear it meshes with on the spindle if it jumps out of gear, current thought maybe brass and making it in 2 parts fixed together. Another option is belt drive with kits around to convert some bench top mills but they seem to be aimed at CNC with higher speeds than standard.
Thanks for the reply. @@SS-Workshop I will keep looking and ask my supplier
Hi found some good info on your channel thanx,,I have a BF -20LV and have brought the Optimum DRO D695 from Machineryhouse,I havent opened the box yet but told it has ss strips for scales ,Do you or anybody who see's this, Are they any good for a DRO thanx for any help
Hi, i understand the optimum DRO uses magnetic scales. I used a ridged type magnetic scale DRO on my previous mill / lathe combo. They seemed to work fine, I don’t recall any issues. They were effectively just oversized digital calipers. The optimum DRO looks to just use flexible tape for the scale which would be easier to install I guess.