Standard 7/8-14 die making machine

[Traffer]

Not having a lathe my Harbor Freight $50 bench top drill press has been used for everything needed to "spin" to bore out. The chuck 1/2" has been replaced with a 5/8" chuck so I have been making my dies with 5/8" bolts. The bolts screw into adapters made from old 7/8-14 dies to use in a standard press. I have been using this set up for about 3 years, always wanted a lathe or at least something that could chuck and spin a 7/8" bolt so I wouldn't have to make the smaller dies and use adapters. One project was to center bore a piece of 1" round bar and tap the inside to 7/8-14. The other end was bored and tapped to 5/8-18. This enabled me to screw a 5/8 bolt in one end that fits the drill press chuck, while the other end contained a 7/8" bolt to cut into a die. It works BUT it is too long and sticks out to far to be practical.
It ended up being a good test to see if a 7/8-14 bolt could be centered this way. Since the bolt centered well enough that way, I know that I can now build a machine (lathe) that does not need a chuck. Instead it will just have a centered hole tapped to 7/8-14. I will be able to just screw a bolt in and start machining.
So here is my idea for a dedicated 7/8-14 die making machine:
Since all I really need is a centered and tapped 7/8-14 hole that spins, I thought of using a knuckle for a automobile drive wheel assembly. I will secure the knuckle with the disk brake rotor mounted backwards. The shaft would be bored and tapped to 7/8-14 .Turning the whole assembly around backwards with the disk rotor in the back, I could use the rotor itself for a v-belt pulley to spin the rig. This would be the "headstock" of a lathe type machine. The only thing I think I would need machined is the spline of the driveshaft that fits into the bearing hub. Just the stub of the spline would have to be bored and tapped to 7/8-14.
I know this is not going to be easy to picture. I am not good at drawing but can try to come up with some pictures at your advise. Thanks Feel free to ridicule me about this. I know many will be itching to do so. lol

[wonderwolf]

Great idea thinking out of the box there!

I take it the bolts have been working well for you in your press? I had a need for punch holders in a swage press and tried to use bolts and found they needed to be cleaned up and the major diameter thinned somewhat to fit right.

Academically I don't see anything wrong with the idea (I'm not a engineer but I did stay at a holiday in express last night). You may find it easier to make a threaded collet, or have one made that will mate up with a simple draw bar, this would allow you to also change "collets" and turn other things as necessary as you may find them to be a consumable over time. I'm not sure how hard the shafts are but I imagine its fairly hard? and tapping large holes and keeping things centered may be a challenge. Somebody with a lathe and a boring bar could make you a 7/8-14 insert that would be true centered.

If you use a lock nut system of some sort you might not run into issues of the work over tightening over time while you're turning the piece. Depending on the work load, heat and such you may find you invented a oversized impact driver and have a heck of a time getting the work out of your chuck, depending on your work holding set up.

I love the idea for a dedicated die machine, curious what the apron and bed would look like. A VERY large I beam with ground hardened round stock rails come to mind, I have a home built machine I purchased from a friend that uses such a set up. One thing about not being good with drawings, I have some nerve damage in one hand and my free hand drawings are terrible. At a book fair many moons ago for $.25 I picked up a couple of copies of "technical drafting" the kind of text book on blueprint drawing that would have been in schools 15 years ago. I've spent a couple hours learning how to draw technical prints using that book and it has helped me blue print my own ideas such as yours and understand possible shortcomings that may crop up when metal meets sweat.

No ridicule here....only a approving thumbs up. Need more can do, sleeve rolling up types like you in this crazy world.

[john.k]

Back to the future.....after WW2,everything was hard to get,owning a lathe was just a dream,many engineering works didnt have one...So people built their own with surplus truck hubs,old car or motorbike gearboxes ,bits and pieces...funny thing is now these machines can be worth big money for the gearbox used...

[Traffer]

Great idea thinking out of the box there!

I take it the bolts have been working well for you in your press? I had a need for punch holders in a swage press and tried to use bolts and found they needed to be cleaned up and the major diameter thinned somewhat to fit right.

Academically I don't see anything wrong with the idea (I'm not a engineer but I did stay at a holiday in express last night). You may find it easier to make a threaded collet, or have one made that will mate up with a simple draw bar, this would allow you to also change "collets" and turn other things as necessary as you may find them to be a consumable over time. I'm not sure how hard the shafts are but I imagine its fairly hard? and tapping large holes and keeping things centered may be a challenge. Somebody with a lathe and a boring bar could make you a 7/8-14 insert that would be true centered.

If you use a lock nut system of some sort you might not run into issues of the work over tightening over time while you're turning the piece. Depending on the work load, heat and such you may find you invented a oversized impact driver and have a heck of a time getting the work out of your chuck, depending on your work holding set up.

I love the idea for a dedicated die machine, curious what the apron and bed would look like. A VERY large I beam with ground hardened round stock rails come to mind, I have a home built machine I purchased from a friend that uses such a set up. One thing about not being good with drawings, I have some nerve damage in one hand and my free hand drawings are terrible. At a book fair many moons ago for $.25 I picked up a couple of copies of "technical drafting" the kind of text book on blueprint drawing that would have been in schools 15 years ago. I've spent a couple hours learning how to draw technical prints using that book and it has helped me blue print my own ideas such as yours and understand possible shortcomings that may crop up when metal meets sweat.

No ridicule here....only a approving thumbs up. Need more can do, sleeve rolling up types like you in this crazy world.

Thanks for the reply.
I may have gotten lucky making the "adapter" that I can chuck into the 5/8" drill press. I just bought a 6" piece of round stock with a centered pilot hole from a local machine shop, $20. I drilled it out with a 13/16 bit and tapped the hole for about 2 1/2" with a hand tap. It turned out centered. When I screwed a 7/8 bolt into it and put it into the drill, I had to use a lock nut to make it spin centered true because it was a tiny bit loose causing enough space to mess up center. But with the lock nut, I had "rechucked" several times and every time center was good.
As far as frame rails and tail stock... not quite figured out yet. I may just bolt everything down well and use headstock from an old larger drill press, aligned, set up and bolted secure. Then I could use the chuck as the tool holder and direct it in and out with the quill handles. This is similar to how I have set up a boring rig before. Basically I set two identical drill press head stocks on opposite ends of the same column. and mounted it horizontal by running it through holding blocks in the center of the column.
Attachment 214856
As long as the initial setup is true, there is no need for ways that stay true to head stock. It eliminates a lot of complicated work.

[Jedman]

All I can add is.. I wanted a lathe for a long time and thru patience and constant watching craigslist, eBay, and letting people know I was looking for one I now have what I want.
I upgraded 4 times and in the end don't have much more than a couple hundred dollars in the machine I have now.
I started out with something similar to what you are thinking about but was designed more for barrel work.
Since you sound to be handy and think of ways to accomplish what you need, keep on with your ideas but with a little luck you might be able to find a real lathe that is sitting somewhere unwanted, maybe in a barn or garage and can go from there. Good Luck !

Jedman