Here is a list of all the postings Steamer1915 has made in our forums. Click on a thread name to jump to the thread.
|Thread: Knurling with a single knurl|
Gray's apprentice tales about knurling remind me of my time spent in a Toolroom in South Africa in the '80's. The inspector and one of the milling machinists joined forces to design and build a small rotary table to fit to their hobby lathes. Progress was made and two very nice tables soon emerged. Great debate then ensued about how to graduate the table with 360 divisions. I added my penny's worth and stated that the only way to do it was to set it up in the dividing head and have a pointed tool in the milling machine's spindle and move the table back and forth etc. They had different ideas and the Miller decided that he could do it alot quicker by merely applying a straight knurl to outside of the rim. He had calculated that using a knurl of a given pitch on a particular diameter would give him 360 divisions. I told them that this was ridiculous and couldn't possibly work, but was ignored. I came in on the Monday morning and asked how the "engraving" had gone, only to be told by the miller that it was spot on. I was duly presented with a table that had 360 divisions! After consuming a large portion of humble pie, the miller told me that the inspector's table was slightly different but would say no more. It eventually transpired that the inspector had paid little attention to the depth of the knurl in his calculations and from that point forward the inspector had to concede that there are only 355, slightly larger, degrees in a circle.
Edited By Steamer1915 on 30/03/2013 09:24:48
Edited By Steamer1915 on 30/03/2013 09:54:04
Fine straight knurl on 66mm dia EN1APb. Sounds familiar - I've just done that, times 25. As Gray says, it's not a two second job, although by number 25 I was starting to get the hang of it!
|Thread: Emco FB-2 Milling Machine improvements|
I have made some stops for the X axis on my Bridgeport. I made these despite having a DRO already fitted. I had a lot of repetitive work to do and needed to be able to approach a position without the fear of over shooting the mark. DRO or not, it is too easy to go past a predetermined position (even heading to zero)and spoil ones work.
Excellent work as usual Gray.
Edited By Steamer1915 on 12/03/2013 18:26:41
Edited By Steamer1915 on 12/03/2013 18:27:22
Edited By Steamer1915 on 12/03/2013 18:29:10
|Thread: No. of divisions|
Don't understand your second line John. However, I've just spent half an hour or so checking the actual measurements on my S7. I clamped a small angle plate to the bed at the headstock end and made sure it was square to the carriage travel so as to avoid sine errors. Using slip piles of various lengths between 1 and 11 inches, I was able to see that the error (such as it is) was no more than 1/2 thou per inch over all measurements. That's close enough for me. In an earlier post, I alluded to the point that I thought that the actual measurement would be slightly longer than the dial reading and this has proved to be the case. Job's a gud 'un!
Thanks for the confirmation about the Myford rack and checking my figures. I was starting to think that I had missed something - even more so after posting!
I absolutely agree about theoretical figures as opposed to practical uses. If I have not completely fried my brain on this, a complete turn of the graduated dial (1" will actually move the carriage slightly more - in theory. I would suggest that (again, in theory) that this is a condition that will only improve as the rack and/or gears wear. So, if the carriage was moved from an unworn section of the rack, to a worn section, any error will reduce. I have one of your dials fitted to my S7 and it has transformed the lathe. I have not come across any situation where I would question it's accuracy. I need to do the 10" slip gauge check just to see where it sits on my lathe. I can certainly see why they are so popular and why so many have been sold over the years. My post was really just to question Anthony's figures and to make sure that there isn't a better iteration. After consulting gear ratio tables in Machinery's handbook, I feel sure that there isn't - or not one that would fit into the existing body. Thank you for your thoughts on this.
Edited By Steamer1915 on 25/02/2013 18:56:19
How have you calculated the 0.866" distance for one complete revolution of the Myford handwheel? I ask this because I make it 0.8617". I arrived at this figure based on the following:- The pitch of the Myford rack is .15708" (3.1416/20dp). The apron reduction gearing is 35/16 which equals 2.1875. One turn of the 12t gear (that engages with the rack) 12 x 0.15708" =1.885". Divide this by the 2.1875 reduction and the answer comes to 0.8617". If the 28/26 gearing is applied twice the distance moved is .99936". The only assumption I have made is that the Myford rack is 20 DP but I have no reason to think it is isn't. I can't see how any of the alternative gearing that you propose, will improve the accuracy.
|Thread: Stuart V10|
On a slide valve engine such as the 10V, the chances of blowing a cylinder cover off or bending the rod or very small. In all likelyhood, all that will happen is that the valve will lift from the port face and the condensate wil escape through the exhaust.
|Thread: NEW Original MYFORD Dickson type tool posts & holders|
I have just received 8. Excellent quality and good comms. I would echo Chris' point about Brunell, having had a very frustrating experience with Graham a couple of years ago.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.