Bolt Plug, Bolt, Hammer clearance?

[brk]

I am back on the Gatling Gun after about 5 months.  I am using bolts and bolt plugs from Cutter and plan to use his design on the striker.

 

The striker head is to be .300\" diameter and the shaft .200\" diameter on the Cutter striker drawings.

 

The hole in the bolt plug in the RGG plans shows .218\" and bolt bore .302\"  The striker shaft on RGG drawings is .200 diameter.

 

The holes in Cutters bolt plugs are running about .221-.223\"  and bolt bores around .318

 

I tried a few different sample hammer shafts. If I make it with a .300\" head and .200\" shaft, it seems to be very sloppy. I am concerned with it hitting the selector switch. I don\'t have my cocking ring or selector switch complete to try these in the gun.

 

But then maybe if there is a lead on the pick-up slot in the selector switch, then having a hammer shaft that is sloppy and can comply to the selector/cocking ring groove maybe a good thing.

 

The hammer springs I plan to use are Lee Spring LC-040D-15M.  I made a striker with a .312 head and .216\" shaft, the spring slides nice on the shaft and the shaft slides nice through the bolt plug.  There is still some wiggle out of the bolt plug and I know it needs clearance. 

 

Anybody got any comments on how much clearance they have used and if it is better to have the striker very loose out of the bolt plug or just a little loose?

 

 

I also tried the samples strikers with a longer 6-32 x 1 1/4\" button head, these are not fully thread.  I tap drilled about 1 1/4\" deep, then use a #29 (.136\") drill about .25\" deep.  Then tapped as deep as I could with a #6-32 tap.  I shorten the screws up some as the threads were not deep enough with what a standard tap could tap. I know I could modify the tap to go deeper, but should still have plenty of thread engagement when setting the .130\" dimension on the underside of the button head to the top of the bolt plug.  My thought is that the shaft of the button head will locate in the .136 hole some and run more true to the 2\" BC of the bolts than if just being threaded.

 

I attached a few pictures of what the screw looks like out of the striker and the screw before shorten.  Seems like this would be an improvement, comments or thoughts on this welcome.

 

 

   

Anybody got any comments on how much clearance they have used and if it better to have the striker very loose out of the bolt or just a little loose?

[Swarfmonger]

The slop as I see it was put there to compensate for a slightly misaligned cocking ring and should always be included since I cannot think of a compelling functionality argument to remove it. A lead on the switch is in my opinion unnecessary since the round head of the bolt combined with said slop  is, in effect, dealing with misalignment issues as well. I would also highly recommend you stop working on the bolts until you have the cocking ring and switch completed and functioning. It will go a long way in helping troubleshoot bolt issues.

[Cutter]

I’m taking apart and cleaning one of my first 6 barrel units

after about 500 rounds. This is the gun I used to experiment

with the hammer/striker shaft. I started with the .300 diameter hammer

at .100 long and had many misfires. I made some split spacers at

.050 intervals. I still had about 20% misfires at .150

When the .100 spacer was added it eliminated the misfire problem.

I ran all the misfired cartridges back through , all firing.

 

My shear screw head gap is .135 on this gun.

After determining the gap, I pinned all screws to shafts

with a 1/6 roll pin    ( 6-32 X 1/2 BHCS )

[brk]

Cutter,

What springs are you using?

 

I plan on using the striker per the drawing below.

 

 

How much clearance do you think you have between the .200\" diameter of the striker shaft and the hole in your bolt caps?  I got my bolts/caps from you a few years ago (great stuff by the way), the holes in the bolt cap are about .221-.223\".  I made a striker with the .200\" diameter shaft and it seems to be too sloppy.

 

If you run that much clearance, then I will do the same. 

 

Appreciate any feedback.

[Cutter]

BRK

I use the same drawing and spring that you have posted.

The shear will never be pulled straight back

with the RG-G design. The cam follower contact

point is over 1/4 “ off center. This will causes the

bolt to cock and rub inside the carrier when engaged

in the cocking ring.

With some additional clearance between hammer, bolt,

and spring assembly it helps eliminates any more drag.

Spring manufacturers recommend a minimum of .010

clearance in a hole or over a shaft.

 

There is nothing sloppy when you have the correct clearance

[brk]

Cutter,

Thanks for the advice.

 

What are you\'re thoughts about using a screw that is not fully threaded, this seems like it would have an advantage of a smooth diameter running/rubbing in the slot of the cocking switch/ring instead of threads under the button head. The clearance drill will allow me use a screw that just has to be shortened and not threaded more.  The screws are from McMaster Carr #91255A155. 

 

I attached a drawing with dimensions and shows the shortened screws and the different tap depth, clearance drill. This would be with the Lee Springs LC-040D-15M.

 

Also, what about material ont eh hammer/striker, what do you use? I am thinking O-1 and hardened to about 55 HRC

 

 

 

Thanks,

BRK

[Cutter]

brk

 

I really like your idea, and the unthreaded extended section

should look great and work very well.

I also have cleaned up on the

under side of the button head. burrs/slag

 

I used O1 and hardened the hammers at home , hard ,

I have no idea how hard. I believe the group bolt project

used O1 too. 

[brk]

Cutter,

Thanks for the feedback.

 

I hate to beat a dead horse about the amount of clearance...…...

 

I took a video of the amount of clearance I have between the hammer/striker shaft and the bolt cap.  It measures about .021\".  Does  this look typically for the bolts-hammer/striker shafts you have made in the past?

 

Just want a sanity check.

[Sparky_NY]

Cutter,

Thanks for the feedback.

 

I hate to beat a dead horse about the amount of clearance...…...

 

I took a video of the amount of clearance I have between the hammer/striker shaft and the bolt cap.  It measures about .021\".  Does  this look typically for the bolts-hammer/striker shafts you have made in the past?

 

Just want a sanity check.

That is definitely not right.   A little clearance for smooth operation is alright but that is a huge amount.    I suppose you could turn some little flange brass bushings and install them in the bolt caps, flange inside.

 

I have no idea where the error came from,  many have made modifications from the original RGG drawings for various reasons.   I imagine you don\'t want to remake any of those parts so the bushing idea is a quick easy fix.

[brk]

The clearance is from a hole in the bolt cap of .221 (the RGG plans say it is to be .218) with a hammer that is .200 (same as the RGG plans).  I measure the movement at about .021\" so that jives with the difference in the diameters.  The hole in the bolt caps from Cutter is .003 larger than the print, but whether there is .018 or .021, it still seems allot to me, however otheres have pointed out that this is likely needed.  It seems that there aren\'t too many people that have actually got these guns to the point of shooting.  An exception is Cutter, who has done several so I will say he is \"the\" \"authority\" on these beside maybe Paul Moore.

 

Cutter, if you see this, can you review the video above and let me know if that is about what you see on your working gats?  I could go a little larger on the hammer shaft, I made a sample with a .216 shaft and it seemed fine with the Lee springs LC-040D-15M, but maybe something along the line of .206, that would leave about .015\" clearance (a little less than the original RGG clearance).

 

Then again leaving it with the .021 maybe just fine if it is typically for what you have done and works.

[bruski]

Here are a couple of RG-G\'s that shoot well.

 

bruski

[Cutter]

The clearance is from a hole in the bolt cap of .221 (the RGG plans say it is to be .218) with a hammer that is .200 (same as the RGG plans).  I measure the movement at about .021\" so that jives with the difference in the diameters.  The hole in the bolt caps from Cutter is .003 larger than the print, but whether there is .018 or .021, it still seems allot to me, however otheres have pointed out that this is likely needed.  It seems that there aren\'t too many people that have actually got these guns to the point of shooting.  An exception is Cutter, who has done several so I will say he is \"the\" \"authority\" on these beside maybe Paul Moore.

 

Cutter, if you see this, can you review the video above and let me know if that is about what you see on your working gats?  I could go a little larger on the hammer shaft, I made a sample with a .216 shaft and it seemed fine with the Lee springs LC-040D-15M, but maybe something along the line of .206, that would leave about .015\" clearance (a little less than the original RGG clearance).

 

Then again leaving it with the .021 maybe just fine if it is typically for what you have done and works.

 

You are in tolerance for a .218 diameter drilled hole.

I checked the movement on one of my older bolts ( like the ones you have )

and had a TIR of .020

I’m measuring about the same as you.

I would not change a thing

Good Luck

[brk]

Cutter - Thanks - Appreciate your feedback and re-assurance!

 

Bruski- yours look great!

 

I hope to be in the group with a firing gun in the \"not too distant future\".  I think I got Paul Moore\'s drum magazine worked out to feed reliably.  It took allot of alterations.  I solved the feed wheel jamming with the pins in the barrel plate, this took longer pins in the barrel plate and some reliefs in the frame rails and the magazine cover to allow for slightly longer pins.  I can crank it empty with the magazine on the gun with the barrel plate pins indexing the feed wheel and it is really smooth. 

 

When I take the magazine off the gun and put shells in, I can rotate the feed wheel by hand and as fast as I can spin it, the shells now come out reliably.  I had to add a feed lip on the left side of the shell opening to get the shell into the feed wheel more reliably, then had to add two lips on the opposite side to get the shells to reliably drop out into the pan.  One lip on the rim end and one in the center of the feed wheel. This required an additional slot in the feed wheel.  All looks good so far, but the proof will be when I get it firing.  I will try to make a separate post on this topic with some pictures.

[Cutter]

Cutter - Thanks - Appreciate your feedback and re-assurance!

 

Bruski- yours look great!

 

I hope to be in the group with a firing gun in the \"not too distant future\".  I think I got Paul Moore\'s drum magazine worked out to feed reliably.  It took allot of alterations.  I solved the feed wheel jamming with the pins in the barrel plate, this took longer pins in the barrel plate and some reliefs in the frame rails and the magazine cover to allow for slightly longer pins.  I can crank it empty with the magazine on the gun with the barrel plate pins indexing the feed wheel and it is really smooth. 

 

When I take the magazine off the gun and put shells in, I can rotate the feed wheel by hand and as fast as I can spin it, the shells now come out reliably.  I had to add a feed lip on the left side of the shell opening to get the shell into the feed wheel more reliably, then had to add two lips on the opposite side to get the shells to reliably drop out into the pan.  One lip on the rim end and one in the center of the feed wheel. This required an additional slot in the feed wheel.  All looks good so far, but the proof will be when I get it firing.  I will try to make a separate post on this topic with some pictures.

 

 

The pin type gearing is very tricky.

The pin lengths on the barrel plate should all be the same.

The pins in the feed wheel releasing the pins in the

barrel plate create the timing. I put a spring washer

on back of the feed wheel shaft as a clutch , so the

wheel would not free spin.

 

 

https://www.youtube.com/watch?v=5H4XEw__Z9w\' title=\"https://www.youtube.com/watch?v=5H4XEw__Z9w\">https://www.youtube.com/watch?v=5H4XEw__Z9w

[brk]

Cutter thanks for sharing your video. The spring tension makes allot of sense.  You\'re absolutely right on the pin timing.

 

I started a new post RGG Drum Magazine - Improvements?  I added pictures and video there of what I have done. Take a look there and let me know what you think.

[JoeCB]

Cutter, ref back to post #3 ... 

\"I started with the .300 diameter hammer

at .100 long and had many misfires. I made some split spacers at

.050 intervals. I still had about 20% misfires at .150

When the .100 spacer was added it eliminated the misfire problem.

I ran all the misfired cartridges back through , all firing.\" 

 

To what do you attribute the improvement ?  Adding the spacer pre-tensioned the spring also increased the mass of the striker, I suppose that both factors would improve the strike force. 

 

It\'s been a long while , but I recently got the gun (RGG) out and resumed work on the miss- fire issues. 

 

Thanks for all the info and help ... 

 

Joe B 

[Cutter]

I agree with you , increasing the mass also increases the force when maintaining the linear dimensions.

 

This example was developed from a formula provided by Lee Spring’s Web-site

http://www.gatlinggunforum.com/forum/index.php?/topic/1552-ignition-problems/