Author Topic: Building a follow rest... twice  (Read 262 times)

Offline WeldingRod

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Building a follow rest... twice
« on: August 10, 2018, 11:01:45 PM »
Since folks here enjoy project logs, I thought I'd post one of mine that I happened to document well.

I've got a buddy that acquired a Hardinge TL10 in college; beautiful lathe, and he made a tailstock to match, as the original had gone walkabout.  Years later, he emails me and says that there is a TL10 on fleabay... in Houston!  I contacted the seller and headed over.  To my VAST surprise, the sign outside reads "Stark Industries". https://madmodder.net/Smileys/default/confused0068.gif Really!  I bought my lathe from Mr. Stark!  No, his first name wasn't Tony.  OH, well.

The TL10 is irritatingly short of documentation and the bits are rare and expensive.  Being a machine nut, I wanted two of the special bits: the taper attachement and the follow rest.  Someone on the Hardinge forum had posted a drawing of the follow rest, and I've seen pictures of a few different ones.  A key thing to keep in mind as you read this: when I started, I had never actually used a follow rest.

The drawing I had didn't actually agree with my lathe all that well, and it seemed to be designed to suit a lathe fitted with a lantern tool post (tool centerline through the compound centerline).  I thought about it a lot, and drew up a follow rest in Autocad.  A bit of fiddling and I ported the layouts to my 3D printer and made full scale models for fit testing.

I ended up deciding it should have TWO sets of fingers so I could support things near the chuck and near the tailstock.  The pieces were plasma cut from my models, and had tabs designed in to make it self-jigging.  I used lots of clamps and a magnetic chuck to get everything assembled for tacking.

Just an aside: a magnetic chuck is a HUGE help for welding and grinding; you can just drop plasma cut stuff on there, mag it down, and grind the dross off quickly!  Grinding welds and stuff is also much easier when the durn thing stays put.


Offline WeldingRod

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Re: Building a follow rest... twice
« Reply #1 on: August 10, 2018, 11:04:13 PM »
I did a lot of tacking and a boatload of welding, intending to make the finished product really nice looking with smooth corners.

Offline WeldingRod

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Re: Building a follow rest... twice
« Reply #2 on: August 10, 2018, 11:07:22 PM »
The three mounting areas were almost co-planar.  I decided (what the heck was I thinking) that I could replicate them into a plane.  I oiled my surface plate, smoothed some foil onto it, spread epoxy on the feet, and set the steady on the foil.  After it was set, I cleared it out of the bolt holes, trimmed it, and did some final sanding.  Then, on to paint!

Offline WeldingRod

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Re: Building a follow rest... twice
« Reply #3 on: August 10, 2018, 11:12:52 PM »
After making the fingers, I finally tried it out!

This is where things got ugly...  It bolted on just fine, but I found out that the tailstock hit the back steady basically all the time, and the front one wasn't where you needed it to be AND didn't have enough room to clear the tools or work.  It did a terrible job of steadying.  Scream! https://madmodder.net/Smileys/default/doh-45.gif

Oh, and I didn't get the fingers where they crossed the center line. D'oh!

After some calming beverages and a few days, I started over.  At least this time I knew where the center line was and the dratted bolt holes!

Offline WeldingRod

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Re: Building a follow rest... twice
« Reply #4 on: August 10, 2018, 11:21:07 PM »
Did I mention that I drilled and tapped a hole in my saddle to make the bad one work?

The second one went together much faster.  An important trick I used: the main structure is two layers of steel.  The fingers go in slots in one layer and the other layer has the matching bolt hole.  I discovered that a steady rest actually wants to have the fingers offset so they can cross, and its nice to have three fingers.  Thus, one of my plates has two slots and the other has one slot.  I designed in a strip that closed each one of the slots so that they would keep their nice precision plasma cut widths during welding.  After the welding was done, I cut off the connectors and finished things on the mill.

Offline WeldingRod

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Re: Building a follow rest... twice
« Reply #5 on: August 10, 2018, 11:29:50 PM »
Of course I didn't take photos of the machining... Drat!  Since I had it clamped to the mill table to do the bottom and take off the connectors, I cleaned up the whole finger slot.  Just couldn't resist https://madmodder.net/Smileys/default/anim_32.gif

And, finally, actually cutting metal!  I needed to extend the threading on a 4" long 1/4-20 capscrew for the taper attachment, so that was my first customer.  The three fingers in two planes worked really well, and I was able to easily cut another inch of threads on it.  The funny shape of the top and bottom fingers are to give you a view of the cut and to clear the tool on the bottom.  They might be version 2B...  At least that didn't require a complete re-do.

Oh, another thing I learned the hard way: roller fingers are a BAD idea on a follow rest.  They gleefully roll chips in between the roller and the work, and push it around.  Simple fingers push the chips out of the way...  At least I learned that on the FIRST one!

In case anyone wants to follow my path (at least the good part), the files are here: https://www.thingiverse.com/thing:2415678

If there's interest I'll type up the taper attachment.  That one came together a LOT more smoothly https://madmodder.net/Smileys/default/nanarocks.gif

Offline PekkaNF

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Re: Building a follow rest... twice
« Reply #6 on: August 11, 2018, 02:42:26 AM »
Very good writeup! I enjoyed reading, you explained nicely rationale of your construction and what you were trying to accieve.

Sometimes I have a "bright" idea too and I decide make a tool, sometimes they work well and sometimes you see first time there is a "slight" problen: looks great but, no chance of working well. THis seems to inversely proportional to amount of time I used for finishing it and getting it right first time.

Did I mention that I drilled and tapped a hole in my saddle to make the bad one work?

Outch!

The second one went together much faster.  An important trick I used: the main structure is two layers of steel.  The fingers go in slots in one layer and the other layer has the matching bolt hole.  I discovered that a steady rest actually wants to have the fingers offset so they can cross, and its nice to have three fingers.  Thus, one of my plates has two slots and the other has one slot.  I designed in a strip that closed each one of the slots so that they would keep their nice precision plasma cut widths during welding.  After the welding was done, I cut off the connectors and finished things on the mill.

I was wondering why the two plates and you insist putting that much weld to warp it. That pretty much explains it. Warpage? Heat treatment?

Oh, another thing I learned the hard way: roller fingers are a BAD idea on a follow rest.  They gleefully roll chips in between the roller and the work, and push it around.  Simple fingers push the chips out of the way...  At least I learned that on the FIRST one!

I kearned the same thing....if the material is that crabby you may use hardened fingers (counter intuitive, but works) or put a large bearing into steady rest and a cat on the pice to protect it. I on the other hand use brass shimstock or greased cardboard between finger and work piece, if the surface is soft. Does not work on thread, for those you need pretty hard fingers ot thread will start driving your cross silde.


If there's interest I'll type up the taper attachment.  That one came together a LOT more smoothly https://madmodder.net/Smileys/default/nanarocks.gif

Please, that would be rally nice. I have not tried a taper attachment.

Offline WeldingRod

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Re: Building a follow rest... twice
« Reply #7 on: August 11, 2018, 12:20:38 PM »
I TIG welded in short sections all over the piece,  and allowed it to get really hot; both of those help keep down distortion.  Preheating would have been better, but I didn't need that level of control.  Hard clamping would also help.  #1 moved no more than 1/16" over its 9" span after a full weld out.

Sent from my SAMSUNG-SM-G891A using Tapatalk


Offline WeldingRod

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Re: Building a follow rest... twice
« Reply #8 on: August 12, 2018, 11:52:48 PM »
Ran across a couple more photos!  I milled the bottom of the follow, and relieved the middle.  I had some fun scraping the steel (carbide scraper of course)!

Yes, steel is a LOT more annoying to scrape than cast iron.  I liked that you can see the pattern develop.  I really didn't need to do it, but I wanted to...https://madmodder.net/Smileys/default/anim_32.gif