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precision angle iron as a machine alignment tool

marka12161

Hot Rolled
Joined
Dec 23, 2016
Location
Oswego, NY USA
I recently bought a pallet of angle plates & angle irons at an auction. About half of them had reamed and tapped holes for mounting & fixturing parts. The other half dozen or so were blank angle irons with smooth surfaces. Some of these had marks suggesting they were used as inspection surfaces.

At some point, i'm going to need a largish precision square to align the dovetailed cross slide ways on my (monarch 16CY) carriage perpendicular to the bed ways (after adding turcite to the carriage V and flat ways). My plan had been to buy a granite square for this purpose but one of the large angle irons is big enough for my purpose. IS there any reason i can't/shouldn't use this as a reference surface assuming i verify perpendicularlity?
 

TGTool

Titanium
Joined
Sep 22, 2006
Location
Stillwater, Oklahoma
Square is square, whatever the form of it. The only other issue is whether one form factor or another is easier to use. How will you set up the square for your crosslide check? If there's a reasonable way to hold and indicate it, that should be all you need.
 

Mcgyver

Diamond
Joined
Aug 5, 2005
Location
Toronto
At some point, i'm going to need a largish precision square to align the dovetailed cross slide ways on my (monarch 16CY) carriage perpendicular to the bed ways (

You dont want it square. Its supposed to have a slight angle so a facing cut cuts slightly concave. 1/2 thou per foot? 3 tenths? Memory fails, I'd look it up before doing it again, but its small. Here's one way to measure it when scraping

5f2uGWS.jpg
 

plastikdreams

Diamond
Joined
May 31, 2011
Location
upstate nj
You dont want it square. Its supposed to have a slight angle so it cuts concave. 1/2 thou per foot? 3 tenths? Memory fails, I'd look it up before doing it again, but its small. Here's one way to measure it when scraping

5f2uGWS.jpg

Hmm now that's an interesting fact.
 

MCritchley

Hot Rolled
Joined
Mar 22, 2007
Location
Milwaukee
I believe Monarchs specification is .0004” per foot. Its scraped in so a stack of faced parts won’t rock.

Check your squares to find one that is off .0004” per foot.
 

Richard King

Diamond
Joined
Jul 12, 2005
Location
Cottage Grove, MN 55016
I'm not a big fan of sweeping the cross-slide off the spindle. So many chances for error. The bed and cross slide need to be square and once that is done you align the head to the bed with a test bar or a face cut, Also as others have said the face wants to be out of square , so if you face something large (big OD) it sets on the outer edge and doesn't tip over. The head should point out to compensate for push away.

Scroll to minute 16 where he checks squareness
Monarch 16" Lathe Restoration: Part 12: Saddle Cross Slide - YouTube
 

marka12161

Hot Rolled
Joined
Dec 23, 2016
Location
Oswego, NY USA
I'm not a big fan of sweeping the cross-slide off the spindle. So many chances for error. The bed and cross slide need to be square and once that is done you align the head to the bed with a test bar or a face cut, Also as others have said the face wants to be out of square , so if you face something large (big OD) it sets on the outer edge and doesn't tip over. The head should point out to compensate for push away.

Scroll to minute 16 where he checks squareness
Monarch 16" Lathe Restoration: Part 12: Saddle Cross Slide - YouTube

Thanks Richard. Yes, i've seen that video and that's basically the set up i intend to replicate. Verifying my angle plates square may be an interesting scraping project in and of itself.

Mark
 

neanderthal mach

Hot Rolled
Joined
Dec 18, 2008
Location
princeton b.c.
It would be more than rare I could ever add much on this forum, but McGyver's post jogged my memory. For any that don't already know of it? Do a Google search for a Dr. Georg Schlesinger and the book he wrote titled Testing Machine Tools. There's a few free online PDF's around of it. But in a nut shell and according to that book I'll quote his numbers to save anyone here some time. Lathes are supposed to be aligned to face "only" concave within .000 mm - a maximum of .02 mm over 300 mm of part face diameter. Or .0000"-.000787402" over roughly 11.8" So as McGyver mentioned, it is pretty small but still more than important for the obvious reasons. While the book doesn't specify, I'd assume that .0000 number is for worn lathes where your at the point of needing corrections, and the second number for brand new or fully rebuilt machines. Imo the Schlesinger information and test methods are great additions to Connelly MTR book.

Not to throw Marka's thread OT, but McGyver also may have also run across the same information I did a number of years ago that mentioned the better lathes had the cross slide ways purposely scraped to provide that very slight inward facing bias. I thought that was true until I started watching Jan Haugjord's videos on YT, and now Richard has mentioned the same about the head stock being off set to do so as well. Jan has also mentioned setting the head stock spindle to point uphill roughly .001" in 12". I now suspect both methods may have been correct at one time, but the head stock off set in both directions might have been found to be better to help compensate for work piece weight and cutting force deflections?
 

Richard King

Diamond
Joined
Jul 12, 2005
Location
Cottage Grove, MN 55016
It would be more than rare I could ever add much on this forum, but McGyver's post jogged my memory. For any that don't already know of it? Do a Google search for a Dr. Georg Schlesinger and the book he wrote titled Testing Machine Tools. There's a few free online PDF's around of it. But in a nut shell and according to that book I'll quote his numbers to save anyone here some time. Lathes are supposed to be aligned to face "only" concave within .000 mm - a maximum of .02 mm over 300 mm of part face diameter. Or .0000"-.000787402" over roughly 11.8" So as McGyver mentioned, it is pretty small but still more than important for the obvious reasons. While the book doesn't specify, I'd assume that .0000 number is for worn lathes where your at the point of needing corrections, and the second number for brand new or fully rebuilt machines. Imo the Schlesinger information and test methods are great additions to Connelly MTR book.

Not to throw Marka's thread OT, but McGyver also may have also run across the same information I did a number of years ago that mentioned the better lathes had the cross slide ways purposely scraped to provide that very slight inward facing bias. I thought that was true until I started watching Jan Haugjord's videos on YT, and now Richard has mentioned the same about the head stock being off set to do so as well. Jan has also mentioned setting the head stock spindle to point uphill roughly .001" in 12". I now suspect both methods may have been correct at one time, but the head stock off set in both directions might have been found to be better to help compensate for work piece weight and cutting force deflections?

Did you ever hear Jan mention "the professor" or the person who taught him to scrape and rebuild? FYI, Jan has attended 6 of my classes, he helped arrange my classes I taught in Scandinavia. I bought the last 8 copies in hardback print of the "Testing Machine Tools" book and the spec's mentioned in the MTR book and the ASME spec's were based on the Testing Machine Tools book IMO. :-)
 

neanderthal mach

Hot Rolled
Joined
Dec 18, 2008
Location
princeton b.c.
Yep he's mentioned your scraping courses in a few of his videos that I've watched Richard. While Keith Rucker's videos are pretty good, Jan's are much more detailed about how to check, scrape to and maintain that three dimensional alignment, so I've picked up a great deal from him already. I'd say your lessons must have stuck very well with him. :-) Jan's a natural at teaching and should have multiple thousands of subscriptions more than he does. Maybe if he did there would be a whole lot less misinformed disinformation on various forums other than this one.

I bought my MTR book long before I ran across any mention of the Schlesinger TMT information and had the same thought as yours after going through it the first time. Quite a bit must have been borrowed from it by Connelly. For reasons unimportant here, I was sort of forced into going with an Asian produced lathe for the last one I bought. It's certificate of accuracy unlike a whole lot of their claims & guarantees of accuracy was at least believable because I double checked them myself. But the line drawings and test methods they used were almost certainly taken directly from Schlesinger's book as well. I still find it odd just how few know of his book today.
 

Richard King

Diamond
Joined
Jul 12, 2005
Location
Cottage Grove, MN 55016
When I was in Germany and Austria teaching, I took one of my MTT books with and One of the students showed me one of the original German language copies as Schlesinger was a German and the English ones were translated. Yes Jan does have some of the best ones on You Tube. I've told him to change the headings or list his with my Name as the other do. Many of the other ones come up if you search on YTube "Richard King Scraping". I get angry with some of these rookies trying to teach on Y Tube and other places. In the Connelly book if you look at the first few pages, he Acknowledges all the people who contributed to the writing of the book. For a book written in 1950's its still a valuable resource and will be for years to come as is the MTT. I also like NYC CNC and Stefan Gottswinter YOU Tube shows. Adam Booth and Lance also have some good ones. :-)
 

neanderthal mach

Hot Rolled
Joined
Dec 18, 2008
Location
princeton b.c.
Yes I'd heard the Schlesinger book was originally in German Richard, but not who went to the effort of first translating it so far. Given it's first edition publishing date, that was likely done either before or just after WW II. I did read a single post somewhere years ago mentioning that there's a Russian language only book somewhat like a combination of what Connelly and Schlesinger did. By just that short account I read it's supposed to be very good if your fluent in Russian. Since I don't read/speak Russian I've never done any searching for it. Have you ever heard or know anything about it?

Overall I'd put Stefan and Jan towards the top of my YouTube list with ROBRENZE at the very top. The man's right up at the genius level for sure. Lance could certainly do his own YT channel, but has said his day job mostly prevents that. The MueullerNick channel did some very good scraping videos in the past, but I think he's sort of given up on YT. NYCNC has some great shop tour videos, but the actual cnc part has little real interest for me other than seeing what top level multi axis technology is capable of. It's obviously non optional for commercial shops, but I guess I prefer more old school methods since I'm not into this to make money. Maybe you should be writing a modern sequel to the MTR book? Add some story's from different jobs as object lessons and break up how dry the MTR book is. As costly and now fairly rare as scraped machine tools are today, I'd say it's doubtful anything new will ever be published about the subject in the future.
 








 
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