weld-on dovetails

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Been spending more time on my milling machine and lathe lately, more than my welder... until nowlThis is just what you have to deal with when mixing new and old tooling.The cutting tool is quite unique, but it's old.  Modern machinists usually have somesort of quick change tool post on their lathe.  So the problem here is I have Lanter-style tool post sized threading tool, but no lantern style tool post.  I have the Aloris knock off.  In order for the two to work together, I need to make this odd sized tool holder-holder.I'm sure if i dig around on the internet enough, i'll find one that's already made, but I wanted to make it myself (heck, that's why i spent the big bucks on the machines, right?)Unfortunately, I didn't have a dovetail cutter... But I wanted the tool holder the same day.So, I hacked one together:  I just welded on the dovetails.First, the easy bit, it's just rectangular slot, nothing fancy:here's the weld-on dovetail.  Basically, I just squared up some stock, and knocked off 30 degrees to get the 60 degrees included, and tig welded it on top, bottom and outside.  I had planned to weld the inside as well, but it's holding up so far:here's a view of the top side.  the weld bead on the top and bottom were faced off.  weld bead at bottom faced off so the tool can sit flush, and top was faced off so I can better see if there was any cracks forming from repeated stress, plus after it's faced off, it's all shiny, so i couldn't resist.everything is cold rolled steel.
Reply:That looks like it would do in a pinch but I would be careful of it.Tim Beeker.
Reply:You might consider adding some socket head cap screws down each side. That would help keep them from wanting to pull away. As it stands most of the strain is taken by the top and bottom weld.   Other than that great idea.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Originally Posted by irish fixitYou might consider adding some socket head cap screws down each side. That would help keep them from wanting to pull away. As it stands most of the strain is taken by the top and bottom weld.   Other than that great idea.
Reply:Originally Posted by VPTThats sort of what I mentioned over on HSM. If a guy couldn't cut dovetails would they hold up if you bolted them on with say 4 tapered head bolts threw the dovetail into the body and recessed flush?
Reply:I like it... definitely thinking outside the box. Proof is in the function. If it works and doesn't flex and/or crack it's all good.I prefer bolting anything that is dimensionally critical because no amount of clamping will prevent movement when welded. As others have mentioned... ideally this would have been dowel pinned and bolted. I think I would have machined a key way in the base and a key in the dovetail to ensure the dovetail is rigid and square. I drew a quick picture to show what I'm thinking. Attached Images
Reply:Originally Posted by irish fixit.........I'd go with socket head cap screws rather than flat head caps screws if there's room for the heads. Mainly because you can get them tighter since they take a larger allen wrench.
Reply:I forgot to add that you did a fine job, and better to build and try something then do nothing while waiting on funds.Please keep us up to date on how well it holds up.Tim Beeker.
Reply:Originally Posted by oxy moronNo room for heads, gotta countersink the bolts.Forhire, this thread is pretty much bait-meat for you  I love what you drew up!  With the precision nature of the dovetail then add on to that the tongue/groove, that's some high wire act that I dare not attempt!  There's ZERO room for error.  Not to mention where to place that tongue/groove must be very well calculated before hand in order to place the dovetail in the proper spot.  someone brought up that they have seen dovetails that were bolted on, so it must be ok.  I assume if the bolts were properly sized, it's probably better than welding it.  I just welded mine because it's quicker for me to do so.
Reply:Originally Posted by forhireI like it... definitely thinking outside the box. Proof is in the function. If it works and doesn't flex and/or crack it's all good.I prefer bolting anything that is dimensionally critical because no amount of clamping will prevent movement when welded. As others have mentioned... ideally this would have been dowel pinned and bolted. I think I would have machined a key way in the base and a key in the dovetail to ensure the dovetail is rigid and square. I drew a quick picture to show what I'm thinking.
Reply:Great job OXY! And if need be in the future you know now you have the capabilities to make the whole piece out of solid. I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys