Surface Grinder Work

[machineman98]

Anyone have a surface grinder?
I need 5 recoil lugs ground.

 

[TAJ45]

You might be surprised how close you can come with abrasive paper, say 240 for the high spots, then 320, 400, maybe 600 according to taste. It has been a while so #s may be off a bit.
Tape corners to very flat surface, bit of light oil and use a full FIGURE EIGHT movement pattern.
With a surface grinder, getting sides parallel is no problem, getting them flat could offer the occasional challenge.

 

[butchlambert]

You might be surprised how close you can come with abrasive paper, say 240 for the high spots, then 320, 400, maybe 600 according to taste. It has been a while so #s may be off a bit.
Tape corners to very flat surface, bit of light oil and use a full FIGURE EIGHT movement pattern.
With a surface grinder, getting sides parallel is no problem, getting them flat could offer the occasional challenge.

You lost me? Parallel, but not flat?

 

[butchlambert]

Parallel lines don't have to be straight

So you are saying they would look like a river on both sides after they left my surface grinder?

 

[geo.ulrich]

Butch, think wall thickness if lug is warped and you don't use a residual magnet they just pull warp down until magnet is released then they just warp back to where they were.

 

[ebb]

Butch you quoted Ramblerman. But on my computer there is not post for Ramblerman. This has happened to me several times lately. What am I doing wrong????

 

[butchlambert]

Butch, think wall thickness if lug is warped and you don't use a residual magnet they just pull warp down until magnet is released then they just warp back to where they were.

George, You didn't know that I did work in the shop and have done a lot of surface grinding. It is easy for me to check on my surface plate. You can shim a bent lug and save it.
You are a Bud and I'm certainly not trying to shame you.

 

[butchlambert]

Butch you quoted Ramblerman. But on my computer there is not post for Ramblerman. This has happened to me several times lately. What am I doing wrong????

He must have deleted his thread.

 

[geo.ulrich]

Butch , yes shimming works good, alittle more painful time wise but it is correct....

 

[butchlambert]

Butch , yes shimming works good, alittle more painful time wise but it is correct....

As you know it ain't worth spending a lot of time on either.

 

[paperpuncher]

Butch , yes shimming works good, alittle more painful time wise but it is correct....

Aint that the truth I did my shaper vice jaws and they were bananna'd i shimmed them ground one side flipped and ground the other side now they are nice. It takes time and patience but the end result is worth the effort

 

[TAJ45]

You lost me? Parallel, but not flat?

Yessir. For an exaggerated example: Pringles in the can.
The magnetic chuck can pull the work pc to the face, be ground, then when released, whatever warpage will spring back.
This is why the better surface grinder guys will shim the part before actuating the chuck if tolerances dictate. I forget the print symbol.

 

[Ramblerman]

I deleted my post because I decided I didn't need to argue with anyone...but no Butch, I'm not suggesting you can't grind flat...but I think you'd agree that not every part that ever came off a mag chuck or other work holding device on a surface grinder was dead flat or parallel...two different things.

 

[Dusty Stevens]

As you know it ain't worth spending a lot of time on either.

Brand new real nice lugs are so cheap i sold my tool grinder. I highly recommend the ones boltfluter sells

 

[Will Henry]

Because I didn't have a surface grinder or access to one, forty years ago, I lapped one side of recoil lugs on a lapping plate until they were flat. Then I stoned the other side until it was parallel. This was tedious work but the result was probably as good as produced by a surface grinder. In fact, it was better than many surface ground lugs I reworked because they were tapered.
If one was to lap both sides, he would, most likely, end up with a lug with two perfectly flat sides which were not parallel rather than the other scenario where you have two sides which are parallel but not flat WH

 

[hdskip]

boy this conversation brings back memories of my years on a surface grinder. Try getting a 12" long piece of D-2 that is .125" thick flat.

 

[butchlambert]

boy this conversation brings back memories of my years on a surface grinder. Try getting a 12" long piece of D-2 that is .125" thick flat.

Been there and done that. I was assigned to making parallels back in the day. In the 60s we didn't have the cheap Wuhan parallels.
My first job in the shop was regrinding end mills. My first ones just rubbed on the heel. It sure gave me a better understanding of what is important in a cutting tool. Our KO Lee was not the cat's meow, but we made it work.

 

[TAJ45]

boy this conversation brings back memories of my years on a surface grinder. Try getting a 12" long piece of D-2 that is .125" thick flat.

Hoo Boy!! That had to be nothing but hair tearing.

Reminds me of early in the apprenticeship, think 12x18" x .5-.7" with nearly 85% gone out of the middle. Radar alignment gizzie. It had been sent out to a contractor "because we didnt have the shop talent to do it". It failed inspection in the shop lab so our journeyman got to do it and I realized later, the man on the job was easily bottom third skill level.
Our supes supe got fired 2 yrs later....taking kickbacks besides out right selling gages we made. More tax $$ in action.

 

[TAJ45]

You are right Butch. Cutting tool geometry HAS to be understood.
I had a couple of small dia treepanning jobs....narrow groove and deeep. Trying to leave enough tool strength/meat without rubbing the outside edge.....mo fun.
I fussed and fussed w that job. Took the finished part to engineering. "Looks good. Where's the other one?" Huh!!?? Print did say 2 ea.....back to sweating bullets.

 

[butchlambert]

I deleted my post because I decided I didn't need to argue with anyone...but no Butch, I'm not suggesting you can't grind flat...but I think you'd agree that not every part that ever came off a mag chuck or other work holding device on a surface grinder was dead flat or parallel...two different things.

I was lucky when I was a young dumbazz, I had a great teacher. Yes, a magnetic chuck can cause problems if you do not understand how to set your parts up.