Difference between sears

[Biscuit451]

What is the difference between an RT sear and a AM/MM sear?

[Ando]

Nothing at all but a bushing.

[Biscuit451]

So could I add the bushing to an AM/MM to make an RT? If so, do you know what kind of bushing t is or where I could get one?

[renie]

Nothing at all but a bushing.

actually the rt sears are a tad longer in length

[Ando]

Is it? News to me

I'm either getting alztimers or someone *renie* is off his meds

[renie]

ill post a pic tomorrow with 1 off each type so you can see the difference

i assure you they are different :) not a lot but different

[Ando]

But will it blend?

What are we talking about 1/8 of an inch 1/4 of an inch 1/2 an inch...or .0010 of an inch? Tolerances, I think you know what they are.

There's no difference other then which stoner was at the machine shop cutting them.

Lol...

It's already been proven they work with the bushing so there's no need to even "measure" anything

[athomas]

So could I add the bushing to an AM/MM to make an RT? If so, do you know what kind of bushing t is or where I could get one?

The sears are the same shape. You could add a bushing, but it would be a bit of work. The rt sear without the bushing has a larger hole than the AM/MM sear. The larger hole is there to accommodate the bushing and still allow the bushing to be thick enough to have some strength. If you have a lathe, you could probably make a bushing that would work, but other than that, good luck.

You might be able to find a larger diameter bushing with an inside diameter that fits the rt sear pin and has the proper thighness. Then drill your sear hole to fit the bushing that you found. Drill slightly undersize to provide a tight fit. Test the fit. The bushing should almost fit in the hole but still be too tight to go. Freeze the bushing and heat the sear. The combination of freezing one and heating the other will change the dimensions enough to allow the bushing to fit the sear. Drop the bushing in place and line it up fast. You have one shot at it. When they change temp, the fit will be so tight, there will be no movement.

[renie]

here you go

[maniacmechanic]

an RT style sear is .035 longer heel to toe ( same with the E Mag , same with the RT carbide/roller bearing one's , how many of you have seen one of them ?? ) , all of the extra length is on the heel ( on/off ) end

For the OP , if you were to put a bushing in a AM/MM sear you could use it in a RT , if you make some ( bushings ) make a bunch ; i've got 6 or 7 AM/MM sears & no RT sears

[renie]

making a bushing is simple but has a thin wall thickness..
I have lots of RT sears if anyone needs some

[zondo]

an RT style sear is .035 longer heel to toe ( same with the E Mag , same with the RT carbide/roller bearing one's , how many of you have seen one of them ?? ) , all of the extra length is on the heel ( on/off ) end

For the OP , if you were to put a bushing in a AM/MM sear you could use it in a RT , if you make some ( bushings ) make a bunch ; i've got 6 or 7 AM/MM sears & no RT sears

I was gonna say that the only important difference would probably be the distance from the catch on the sear to the part that trips the on/off, but I could be wrong.

[maniacmechanic]

I was gonna say that the only important difference would probably be the distance from the catch on the sear to the part that trips the on/off, but I could be wrong.

this is within .000 of being the same ;
I measured 6 AM/MM sears & it was different on each one , but all were within ,010 of each other
My carbide sear measured about .020 shorter on this ( catch was sharp like a knife , no wear )
E Mag sear ; measured the same as the AM/MM sears ( in the .010 range )
The RT sear was already back in the gun , I wasn't going to take it apart again

The Hole ;
AM/MM sear ; hole is .190
RT sear ; hole is ,125
so the wall thickness on the fabricated bushing would have to be .0325 , pretty thin bushing
The Carbide RT sear has a Roller bearing in it , OD is .250 width is .245
The Hump where the bushing sets is the same outside dia. on both sears , so it may be easier to drill the AM/MM sear & install a bearing

[athomas]

actually the rt sears are a tad longer in length

Yes, but the extra length isn't as important. All they did was make the lobe wider for a greater range of rotational operation.

[Ando]

Yes, but the extra length isn't as important. All they did was make the lobe wider for a greater range of rotational operation.

Just let him have this one

3 hairs longer is 3 hairs longer.

@ renie