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New member looking for a couple items for my RF-31

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zakruvalcaba

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#1
Hello all! New member here. Just picked up a RF-31 on a really good deal. Looking to fabricate some small parts for my boat and do some gunsmithing work including completing some AR15 lowers. At any rate, I'm looking for the cross bolts that tighten the head to the column and prevent it from moving side to side. From what I can tell they appear to be 11/16"x6 bolts. It appears as though the previous owner used 5/8"x6 bolts and the hex pattern doesn't fit the hex pattern on the head so it causes the bolt to turn when I attempt to loosen or tighten from one side. I end up having to jam a screwdriver in there to secure the bolt head while I turn the other side...it's kind of a pain. I bought 3/4"x6 bolts and they're just a hair too big so I assume they are 11/16. I'm having a heck of a time locating these bolts...anyone have any idea where I can find these? No luck at HomeDepot, Fastenal, or Grainger. Thanks!

Zak
 
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Billh50

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#2
Could they be metric?
 

zakruvalcaba

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Could be. I don't care either way, I just want to make loosening and tightening this thing easier. That would make them 17mm correct? Any idea where to find a 17mm bolt that is 6" long then?
 

Dave Paine

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#4
I agree with Billh50, these are likely to be metric.

5/8 = 0.625in.
16mm = 0.63in

Check the pitch with a thread gauge. May be coarse or fine thread.

Best place to find these is either an online site which sells metric hardware, or by machining 3/4in bolts to size. The diameter needs to be machined on a lathe and the head machined on a mill.
 

brino

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#5
If one nut is captive, you might be able to use threaded rod(cut to required length) and two nuts.
-brino
 

zakruvalcaba

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Thanks guys. One side is captive....the threaded rod may work if I can find a nut that'll fit into that area. I'll get a picture together tonight to show my delimma.
 
R

Robert LaLonde

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#8
The manual for the RF-31 shows them as 5/8" bolts (#52).

https://www.pts-tools.com/MSDS/RL80RF313.pdf

Bolt Depot shows the hex head width for a 5/8" bolt as 15/16"

https://www.boltdepot.com/fastener-information/bolts/us-bolt-head-size.aspx

Hope this helps.
I got rid of my RF30 earlier this year so I couldn't walk out and check. I would note that I have gotten many a Chinese fastener that did not have a standard size head on it. In some cases SAE fasteners with clear metric size heads.
 

zakruvalcaba

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What the manual shows and what actually fit are two different things apparently. I'm using 5/8" bolts now and the casting on the head is too big for the heads of the bolts. They freely spin....
 

zakruvalcaba

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zakruvalcaba

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I just ordered the following:

2 5/8x6 bolts (heads are 15/16")
2 1/2x6 bolts (heads are 3/4")

We'll see if that works....
 

Silverbullet

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#12
Could you put a washer or cone type washer ,,wheel lug washer,,. It would help keep center and tighten better.
 

zakruvalcaba

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Could you put a washer or cone type washer ,,wheel lug washer,,. It would help keep center and tighten better.
I'm not sure what you're referring to. Here's a picture of the casting side of the hex bolt. As you can see these are replacement 5/8" US-made bolts and they spin in the head casting. I have some new ones on order from bolt depot and just waiting for them to arrive.

Photo Oct 25, 8 35 59 PM.jpg
 

pberry26

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#14
Ace Hardware, Home Depot and Lowes have a huge array of drawers with special hardware, bolts, nuts, washers, up to Grade 8, or the Metric 10.9.
 

zakruvalcaba

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Ace Hardware, Home Depot and Lowes have a huge array of drawers with special hardware, bolts, nuts, washers, up to Grade 8, or the Metric 10.9.
I tried Lowes and Home Depot and they only carry 5/8" and 3/4" bolt with the same sized heads. Those two stored were my first options...
 
R

Robert LaLonde

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#16
You have a mill. Make a hex spacer that goes under/around the bolt head that just fits the space on the mill head. It might be easier than chasing down a wrong headed bolt. You probably want a bolt that just fits the hole through the machine.
 

Silverbullet

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#17
Ok I now understand the problem . Is the other side flat ? If so what you need is the nut to be in the hole with the hex. And the bolt head to the flat. If it's spinning in the hole try a double tooth washer under the nut it will help stop the spinning . If it don't work you'll need to either shim the flats or find oversize nuts or make them. But I do know the nut goes in the hole not the bolt.
 
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Robert LaLonde

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#18
Ok I now understand the problem . Is the other side flat ? If so what you need is the nut to be in the hole with the hex. And the bolt head to the flat. If it's spinning in the hole try a double tooth washer under the nut it will help stop the spinning . If it don't work you'll need to either shim the flats or find oversize nuts or make them. But I do know the nut goes in the hole not the bolt.
I forgot that sometimes the bolt head and nut are different wrench sizes. Not usually though with the decent quality stuff I get from a decent bolt distributor. That does however make make the self machined solution easier if a shelf solution does not present itself. Machine a nut to fit the socket in the machine head.
 

Canuck75

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#19
I'm not sure what you're referring to. Here's a picture of the casting side of the hex bolt. As you can see these are replacement 5/8" US-made bolts and they spin in the head casting. I have some new ones on order from bolt depot and just waiting for them to arrive.

View attachment 245303
Had the same problem with my King PDM30. I measured the difference between the replacement bolt head size and the pocket in the casting, divided it by two and got some sheet material a little less than that thickness. Out of that material I made some washers to fit the bolts with ears that folded back against all 6 flats making the bolt head the correct size to fit the casting pocket. They do not let the bolt turn , tightening or loosening. I used grade 8 bolts. The originals were grade 5 at the most.

Canuck75
 
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Canuck75

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#20
Found a picture of the washers I mentioned to effectively increase the size of the bolt head. It might help if you haven't solved the problem as yet.

Cheers
 

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