Interesting! I have burnished surfaces of steel bar stock in the vice after draw filing. A fully hardened and polished round bar works well, but I've never tried it in the lathe. It looks like it would be useful for reducing a diameter by a few microns to improve a fit too.
Thanks for the comment. I agree about the reduction in diameter. I need to do some trials but I think it will be a great tool for use in finishing bearing seats as well as final finishing. Cheers SteveO
Try using Belleville washers to preload the diamond burnishing tool. It requires much more force to work. Cogsdill diamond burnishers work very good, as well as their rolling element carbide variant .
The diamond surface looks like it might have "cut" a little bit on the leading point edge, as opposed to the tangent surface from the ball bearing. Interesting work. Would be intrigued at the difference in surface area of the contact, and the toolhead pressure of the carriage
I’ve never owned or used a burnishing tool. I was taught at a very young age (12) to cut to diameter with a three pass finish. If the final finish was not good enough I would revisit the speeds and feeds. Or tooling sharpness. But I can certainly see that tool being a bacon saving option. Especially when you’re invested heavily on a workpiece. But I always enjoy your videos and your craftsmanship. After watching your videos I’m convinced you are or was at some point a machinist, or at the very least an expert DIY’er. lol 😂 Thanks for the inspiration. 🍻
Nice result with the ball burnishing. I think that the dressing diamond was doomed from the start. I will be making a ball burnisher along your design lines. Thanks.
Thanks for the comment. I have thought about that but for the tool to work effectively the support bearing needs to be directly behind the point of contact of the ball. Not sure what an angled setup would do as the ball would not be properly supported. I did watch your video (I'm a big fan of your work and a subscriber) and saw your tool. Perhaps you have already solved it. Cheers SteveO
@@theoutbackshed I used a stock size transfer ball. They are used for rolling parts across tables, the ball sits in a hemispherical cavity on several much smaller recirculating balls. I've tried mine on a taper which worked fine. For some time I have been contemplating burnishing a complex profile to see if it works. Perhaps with the huge resurgence of these tools on RU-vid it may be time to have a go.Thanks for the sub. Edit: video now live.
Very interesting. I’ve never thought of trying this, but now I think I will. What comes to mind are several things. Burnishing stainless should give a decent amount of work hardness. Obviously, that would require some experimentation, as will the amount you need to over diameter the parts before burnishing. Like you said, the diamond is designed to cut grinding wheels. Sapphire balls are easy to obtain (I have a bunch from my chemical adjustment feed tubes) they’re hard enough, though I’m not sure if they would hold up. Carbide would be good to try instead of the diamond, as you can finish the tip to a high polish ball. I’ve done that for other purposed using 100,000 optical diamond polishing compound. Very nice build.
Thanks for the comment. You raise some interesting points. A carbide rod properly shaped and polished might be a good replacement for the diamond tool, not sure where I would get a 3/8" piece of carbide 2 1/2" long though. I do have some work to do to work out the diameter loss with the ball burnisher but as you say, some experimenting is needed. Cheers SteveO
That’s very interesting. That’s a whole different level going to carbide. That could be a pretty durable solution. Getting a feel for how it reacts as far as tool pressure versus travel on a regular repeatable scale, I worry about the steel balls causing damage to your workpiece. But all this is new to me so I’m just trying to take it all in. Lots of really good content. I love manual machining. 🍻
With the ball burnishing tool how much tool pressure are you putting on the material or once you make contact how much are you advancing the tool into the work? Nice work on the tools.
Thanks for the comment. So far only very little pressure. I haven't measured it or taken note of the advance, I'll give some feedback on that in future projects. I have the impression (rightly or wrongly) that doing the 2nd pass on reverse feed provides an opportunity to obtain a better finish by rolling the pattern in the opposite direction. I need to do some experimenting. Cheers SteveO
Burnishing does a great job of achieving a good finish to a point. However I prefer to lap a diameter to size if I need to achieve size and finish and missed it with the turning tool. . Laps are easy to make from a piece of wood. But the burnish will give better finishes of many machines than a tool ever could. Even things like diamond reams often do more burnishing than cutting. You can get carbide balls as well and they have an excellent surface finish so should be as good as the steel balls.
G'day Steve, nice job there. If you dont have a reamer you can make a drill cut on size by using an oilstone to round off the corner of the cutting egdes . Drill an undersize hole first, just like you would with a reamer, and remeber to sharpen the drill again before using it as a drill
Nice machining, but more elaborate than need be. A brass rod, bored to receive a silicon nitride ball bearing and burnished to keep it captive works well. Ends up looking something like an oversized ball point pen tip. (Steel ball bearings seem to gall in this application, silicon nitride works well.)
Thanks for the comment. That's an interesting idea. There is a limitation on my tool getting close to a shoulder and I have been looking for an opportunity to make a tool that can burnish corners and put a hard shoulder. I will research your suggestion, thanks. Cheers SteveO
G'day Steve, new subscriber here, great result with the ball tool, diamond not so, but I really didn't expect it to in" out of the packet" condition. If that were mine I think I would sacrifice a thousand grit diamond Filing stick or better still if you have those cheapo diamond paste sets and use that on a wooden lollipop stick to round the diamond point. Just by fitting the tool in the lathe chuck and rolling the lollipop sick over the end gradually going down the micron grades until it looks smooth under the microscope, covering the ways of course. Worth a try I'd think. I bought a set of the diamond pastes off of eBay a few years ago and they cost me less than ten quid and work very well for polishing stuff. I'm confused, your Colchester lathe looks brand spanking new, but I thought they went out of business ages ago. Has the name been bought and they're being made in the far east now? I'd be interested to know your thoughts on the quality. Cheers from the UK
Thanks for the comment. I was contacted today by a company called LIVETOOLS, apparently they stock diamond burnishing tools but they are outside my budget. Still thinking about how to proceed with the diamond stick but there's no hurry. Colchester lathes are still made but not in the UK anymore, Taiwan I believe under license. Colchester Lathes are available here in Australia but I'll stick with mine I think. My Colchester is 40 years old, I bought it in 1984, if you look after your lathe it will look after you. There's more information on this in my video on Lathe Maintenance. Here's the link: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-OqT_e_7NPM8.html Cheers SteveO
Thanks for the comment. I used Caswell black oxide solution and penetrating sealant (oil). Here's the link: www.caswellplating.com.au/store/store.php/products/black-oxide-kit-bo1 Cheers SteveO
Does burnishing change the dimension of the part, and if so, how much? Thanks. What about surface hardness? Does it make the surface harder? I would think so.
Hi and thanks for the comment. The machined bar registered 24.921mm on the micrometer, the ball burnished reading was 24.918mm. That's a reduction in 0.003mm or 3 microns. Different metals would likely give different results. 1020 steel would likely not work harden but I would expect other metals like 1045; 4141 and Stainless Steel likely would show an increase in surface hardness. Cheers SteveO
Thanks for the comment. It's relatively easy to get a good finish on brass so I'm not sure I would burnish it. That said, it would be interesting to find out if it would work harden. I have my doubts that it would. Cheers SteveO
Hi and thanks for the comment. The machined bar registered 24.921mm on the micrometer, the ball burnished reading was 24.918mm. That's a reduction in 0.003mm or 3 microns. Not sure how repeatable this would be and I did expect it to change on different materials. Cheers SteveO
@@theoutbackshed amazing, thank you so much for taking the time to reply. thats basically negligible for almost everything i do, so will definitely experiment with this technique.
good thing you made 2 ball burnishing tools and not 2 diamond ones, I think most people would have agreed with your indicial assessment that the diamond would be too sharp to provide a good finish. *shrugs* maybe if the feed was extremely slow, it would have cut with a similar finish to the carbide turning tool? very nice work on the holders. i might try and make something similar one day, if i ever get the time lol
Thanks for the comment. Yes the diamond was always a long shot. I did hear reference in the comments of another build that it might be worth trying. Oh well, I haven't given up on it yet. Cheers SteveO
Thanks for the comment. It certainly improves the surface finish on mild steel. 4140 and 4340 produce good finishes with decent speeds and feeds as does aluminium and stainless. So it will depend on what I am making. It may be a good finishing tool for good surface finishes with minimal metal removal? Cheers SteveO
Thanks for the comment. I understand that a genuine diamond burnisher can be purchased for around A$400 but that's beyond my budget, however, the opportunity in this project was to see if a diamond wheel dresser could be setup to perform this job. As the video showed it was not successful probably due to the pointy nature of the diamond rather than having. smooth end. It was a fun build though and I view it as still a work in progress. Cheers SteveO
Hi, Thanks for the comment and the observation. It's a SANDVIK R300-025A20-10M double insert end mill. It has two R300-1032 inserts and a max RPM of 28,500. Its a nice end mill. Cheers SteveO
Thanks for the comment. The pressure applied to the tools are no more than would be applied during normal turning. Push knurling would be far worse (I never do push knurling) Most of stress would be in the cross slide lead screw and nut. There would be no issues for the headstock or tailstock centre bearings. Perhaps I could design a pinch type ball burnishing tool? Cheers SteveO
@@theoutbackshed Very interesting video. Thanks for posting. See "Enots Engineering"(Alan) He made plain wheels for his scissor type knurling tool with pretty good success. Regards from the uk.
Thanks for the comment. The reamer was running correctly, it is a reverse spiral reamer and is designed that way. After I remove the reamer I show it to the camera. Cheers SteveO
