GAV694 23 #1 Posted May 18, 2014 Not sure which section to post this in so I thought I would try here. I am restoring a Gutbrod rotovator but found a female-female splined coupler inside the gearbox has split due to the shaft inside it rusting and swelling up, I cant just weld it up as a oil seal runs on the outside of it so I need to find a replacement It has 13 teeth and the shaft that fits into it measures 21.36mm in diameter, does anyone know if this is a standard size and if it is metric or imperial or even better where to get one cheers Share this post Link to post Share on other sites
GAV694 23 #2 Posted June 3, 2014 Here are some photos of what I was trying to explain Share this post Link to post Share on other sites
sten 84 #3 Posted June 3, 2014 Could it be welded then ground and polished Share this post Link to post Share on other sites
Stormin 4,458 #4 Posted June 4, 2014 Could it be welded then ground and polished That's a possibility if push comes to shove. A good V for the weld and careful clean up. The Fife Ploughman will know about spares I should think. Share this post Link to post Share on other sites
Anglo Traction 998 #5 Posted June 4, 2014 Not sure where on the Shaft you have taken the measurement (Smooth part of shaft or across the O/D of the splines), 21.36mm converts to 0.8409" and the nearest fraction (over) that size is 27/32" (0.8437"), suspect also being central European make, it will be metric . I have no idea where you could find a likely replacement, but may be worth researching to see if the gearbox type/design was also used on other machinery as well. If you have no luck with a replacement, a good machine shop can accurately grind the O/Dia down, weld it, heat shrink and weld a sleeve on to re-establish the O/D and the Oil Seal faces. You can also obtain Shaft Sleeves that act as a new running face for the Oil Seal e.g. www.sealmasters.co.uk. It is also most likely the Crack will have to be cut/cleaned right through into the Spline groove, as I can see in your pic that the Crack is full of corrosion and expanded the piece making the shaft splines a 'looser' fit in the bore than is desirable . I imagine having a new one Broached will be OTT on cost. So there are ways to repair it. Hope you get It sorted whichever way you choose. Share this post Link to post Share on other sites
GAV694 23 #6 Posted June 4, 2014 Thanks for the advice guys I cant find a replacement so it looks like it will have to be repaired. I think my initial thought that rust swelling had cracked it was wrong. it turns out that the shaft and gear that fit into the coupler are an interference (extremely tight) fit as the sides of the male splines are square and don't tapper to suit the coupler. I think I will alter the shafts to make them a 'close' fit and use some Loctite 628 or similar to hold it in place. This will hopefully prevent it from cracking again. For dressing the OD I have a few options, the oil seal that was fitted had a 30mm bore but I can get one with the same OD and a 31mm bore so if I have a bit turned off the coupler and use the bigger oil seal I can have a sleeve made with a larger wall thickness and press it on. That's the theory anyway Its not too clear but this is each end of the shaft, one edge with chamfers the other without Share this post Link to post Share on other sites
GAV694 23 #7 Posted June 5, 2014 OK its welded now and I will have it turned down slightly and fit one of these so that I can stick to the original size seal http://simplybearings.co.uk/shop/Engineering+Parts-Shaft+Repair+Sleeves-Metric+Shaft+Repair+Sleeves/c4713_4847_4849/p182541/SKF+CR99120+Hardened+Stainless+Speedi+Sleeve+for+Shafts+29.31-29.41mm/product_info.html Share this post Link to post Share on other sites
