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View Full Version : To a kid with a lathe, All the world is turning stock...



E.T.Jr
06-29-2008, 01:34 AM
I just finished up a repair on my Sears 42" mower deck that I thought would help out some of the other folks just getting into lathe work.
The linkage that engages / disengages the blades would jam up due to a worn out roller.
This means if you turned off the tractor it wouldn't start again due to the mower deck interlock switch. This usually ended up dropping the mower deck to free up the linkage, and get the interlock switch to close again.
The roller spun on a grade 5 shoulder bolt, which had also been worn half way through. Checking with Sears, they don't sell those parts, but for around $90 they would sell the whole linkage assembly made of Chinese "Butter Steel" and plastic. Not wanting to buy a new one of these things every other year just because of something a simple as this roller, I started wondering what type of material I should use for the roller, Drill Rod? Tool Steel? Depleted Uranium???
The roller measure out around 0.375" and I noticed that it was worn at the edge where it shoulder bolt reduced to the threaded portion of the bolt. I figured that if I put a flange on the new roller on that side that would avoid the issue in the future.
So I hit the local Tractor Supply store since they are a good source of graded hardware with the intent of finding that shoulder bolt. Well, I didn't find the right bolt, but looking at the bins of hardware turned a light in my head... Why not use a grade 5 bolt as stock for the roller...
I loaded up a bag with some 1/4"-20 and 1/2"-13 bolts (gotta love stuff that sells by the pound) and headed home to my 12" Craftsman/Atlas lathe.
To make a short story long, the grade 5 steel bolts turn beautifully. I started to try and bore one out for the 1/4" which is the bore of the old chewed up roller, only to find that the only thing that appeared make headway was my carbide center drill.
Was Grade 5 that hard the a regular bit wouldn't touch it?
I started to check out getting my hands on a Cobalt or solid carbide bit since my HSS bit just jammed and burned. I quizzed on of the machinist at work and he said "Bull" and that I must have either cheap bits or dull bits.
I snagged a 1/2" bolt out of the car, and in no time we had that critter chucked up in one of the Hardinge collet lathes and he pecked out the 1/4" bore I needed.
Later that night I had the bolt home and chucked up in my lathe. After truing up the unthreaded part of the bolt and turning down the hex head, I ran a parting tool in partially to set the roller length, and to establish the flange. The flange trued up just under .475" in diameter, and is about 1/16" thick. I turned the rest of the 1/2" stock down to the .375" diameter of the old roller.
Next I tightened a 1/4"-20 in the lathe and center drilled the threaded end for support in a center. After squaring up the shoulder at the hex head, I turned off the threads to bring the diameter to the 10-24 threads of the original bolt, and turned the unthreaded portion to proper length. I cut these threads with a 10-24 die and trimmed the threaded portion to length. The mower deck linkage now works like a dream...
http://i280.photobucket.com/albums/kk169/spambucket_01/Turning_2008_0626004.jpg
http://i280.photobucket.com/albums/kk169/spambucket_01/Turning_2008_0626006.jpg

The morale of this tale:
1.Graded hardware (Grade 5, Grade 8) makes great stock for small turning projects.
It's low cost, readily available, and with a sharp cutter is a real pleasure to turns.

2.Make sure your drill bits are properly sharpened. I know it sounds stupid, but what I thought was reasonably sharp, may not be sharp enough. Even with cutting fluid I couldn't get that blasted drill to feed. I rarely have problems with getting a drill bit to cut for me, so this created a bit of frustration.

3.Don't be afraid to bump up the speed on your lathe. I found this small diameter work turned best with my lathe in the high range of speeds. Follow reasonable chucking practices, and you will be rewarded...

Fasttrack
06-29-2008, 01:46 AM
Ahhh ... isn't metalworking wonderful? I reckon it would be damn hard work for all the pro's out there, but for a "serious DIY'er", machine tools are beautiful.

I think it would be great to settle in a small town and open up a machine shop part-time as a way to help the community and help pay for my hobby. A shop that could specialize in repairing old ag equipment or other one-off type parts that weren't too time sensitive. I know a machinist in my brother-in-law's town that charges under 10 bucks an hour and does fantastic work. Not sure how old he is but he worked as a blacksmith when he was a kid in the brick factory before they got "modern" machine tools. Modern machine tools to him are any that run on electricity instead of overhead belting! I want to be like him when I'm an old man.


edit: I'm starting to sound like an old man... rambling on ;) Nice work. Grade 8 can be tough to deal with but Grade 5 is not too bad. Keeping sharp bits for your lathe is very important, especially for harder material. We recently found some "butter steel" from china. BIL bought a set of "Titanium High Performance Drills" for about 10 bucks. They weren't even worth $1. I tried to drill through the side of a grain bin - thin material and soft for metal. The bit was smoked, and I mean smoked, within a matter of seconds. I was thinking ... something doesn't feel right and I looked at the bit. The tip was round :eek: Switched to a quality, made in usa bit and it went right through no problem :rolleyes:

ckelloug
06-29-2008, 04:08 AM
ETJr,

It's funny you should post this about using bolts as stock. I was out in the shop today trying to singlepoint thread a 6" long 3/4 inch grade 5 bolt beyond the two inches of thread it came with to use as a leveling screw for the bridgeport. I had to trash the first bolt I tried. I got the second one to thread but ingenuity set in and I started making a replacement gib adjustment handle out of it for the BP since it came rusty and bent from the previous owner.

The grade 5 bolt is good stock and about a 4 inch one including the head counts as a DIY teardrop shaped bridgeport gib adjustment kit ;)

Regards all,

Cameron

Lew Hartswick
06-29-2008, 08:09 AM
First thing that crosses my mind is : How in the world did you ever leave that "interlock"
in existance long enough to wear that bolt that much. Within the first week I'd have had
that thing eliminated. :-) But good work on the bushing.
...lew...

E.T.Jr
06-29-2008, 12:05 PM
I had picked up the tractor used, so it was already worn when I got it. As far as the not fixing it sooner part, I didn't have the lathe until recently.
I finally convinced my dad to part with the lathe before he went into the nursing home, but that is another story in itself.
We all at one time or another started at a point where we didn't have a lathe, or really much access to one, and that's the point I was at until this past year. Believe me there has been many years of blind struggle. I even have some patterns made to cast a Gingery type lathe, but I didn't get to pouring them yet.

I learned the importance of good drill bits a while back, and the one I tried using was from a set that came with the lathe. Usually my dad bought pretty good stuff, but this must have been an import set.

Carld
06-29-2008, 12:49 PM
I use grade 8 bolts to make parts too. Isn't it great to have a lathe to fix stuff with.

Fasttrack said, "I think it would be great to settle in a small town and open up a machine shop part-time as a way to help the community and help pay for my hobby."

I thought the same as you but before you do anything go to your county zoning and business license dept and make some inquires. You will soon be made aware they don't want the small operator in their county or city. The requirements for a machine shop in many places puts you in the manufacturing zone and it aint cheap or practical for a one man part time shop.

Fasttrack
06-29-2008, 01:44 PM
Maybe I'll just have to do it all in cash then ;)

:D

No officer, this isn't a machine shop. It's a restaurant, the machines are just there for authentic ambiance.

ckelloug
06-29-2008, 03:18 PM
Fasttrack,

Come to Huntsville, AL. The building inspector didn't even balk when he saw the machines. The utility guys didn't balk either (though they did cuss) when they saw the 400A commercial service they needed to reconnect to the house in support of the shop. And I live in a strictly residential neighborhood. The ordinance here says that occupations traditionally done at home like modelmaker can be done at home as long as noise or light don't leave the property. If I ever get asked, I'll tell them I'm a modelmaker ;)

--Cameron

38_Cal
06-29-2008, 10:30 PM
Montezuma, Iowa, population 1,500, NO building inspectors or zoning. Got to get a building permit to do exterior stuff, not so for interior. If you want to do your own wiring past the meter, that's up to you...I had a licensed electrician do my installation of the new service from the house to the shop...I'm electrically challenged.

David
Montezuma, IA

Fasttrack
06-29-2008, 11:25 PM
LOL

Yep, thats how the small town where my brother-in-law is. I think they're just happy when "new blood" moves into town!