Knowledge You Can Build On — Est. 1998
How to attach tips.
Don Henthorn
>I made a curved hollowing tool today because I am making a smaller hollow form than my Laser rig can handle. I am using a short piece of 3/16" tool bit for the tip. I was going to braze it on the drill rod but rememberd that some of you glue them on with cyanocrylic. I may try that but first I wondered if anyone had ever had trouble with the heat of turning causing the glue to let go. Thanks for your experience.
Re: How to attach tips.
Al Crandall --NE of Indy--
>Hi Don. I don't think you will get it hot enough while turning to make the CA let go. Grind might be another matter, but I am not sure. My problem with using CA for attaching is that it is brittle and will not handle shock well. Possibly the people who advocate using CA are all using it to fix a tool into a hole where the shaft will absorb the shock. I'd be wary of just butting the hss to the shaft end like we do when silver soldering. But I've been wrong before!
Re: How to attach tips.
bill Crommett in seneca
>Don: I have made a number of hollowing tools that were heat bent after drilling a cavity in the end to accept a scraping tip. The cutting (or scraping)tip is usually fastened with 5 minute epoxy and this can be heated directly to remove or restore the tip after re-grinding. I have never had one come loose from cutting heat.
Re: How to attach tips.
Dale Cook
>Hi Don. I have made similar tools and have had no problem with the glue (cyancrylic)letting go.I don't think sharpening gets it to hot,then to replace the tip just hold a torch to the tip and heat it up and it will pop out.
Re: How to attach tips.
Don Henthorn
>Thanks gentlemen. This is a smaller tool. I used 5/16" drill rod, bent the tool and ground a flat on the end about 5/16" wide. I am going to try just glueing the bit to the flat and see how it goes. Will post a pic after the epoxy in the handle dries.
Re: How to attach tips.
John Lucas
>Don
If you drill a 1/4" hole the bit will be a very snug fit. I actually had to knock a tiny bit off the corners of the last bit I made to get it in the hole. CA or epoxy work well. If you don't like that drill and tap a small hole and put in a setscrew.
Re: How to attach tips.
Barry Irby
>I have made a number of tools that have a HSS tip glued with CA into a softer steel rod. David Ellsworth does his that way. They work well and have never had one fail from grinding or in use. When it is time to replace the tip, heat it with a torch and it pops outs.
I don't think gluing one to the surface or to the end would work. In the case of inserting the tip in a hole, the glue only holds it in place and keeps it from rotating, the sleeve or hole absorbs all the shock and stress.
