M38 Carcano Lower Band Swivel STUD

Hello fellow Carcano aficionados! I am stuck in the house with a bad case of gout so I thought I would use this time draw up a M38 Carcano Lower Band Swivel STUD. I made one awhile back and it came out OK but maybe not to perfect dimensioning. Another forum member has asked me about how to make one so I thought if anyone is interested in measuring an original we could come up with an accurate drawing and leave that as a post on the forum. If say a couple of people provide dimensions we can come up with some good numbers. I will then redraw to scale and leave as a post on the forum. This little part is always hard to find. So if you have a digital caliper and original stud handy please measure the Dim’s A thru N and post or send me the dimensions. I am not getting anything out of this other than being able to make a good part myself. Also I will later do a step by step with pictures on how to make one when my foot gets better. It looks more complicated than it is but helps to have a lathe and mill.
Salt Flat

Will try and do some ciphering directly.

Moderator Edit:

The drawing in this post has been deleted as it it is later superceded with an updated version.

Did the measurements on one. Would that suffice or do you want more?

You should go into the small part business. There is a definite shortage of parts. Notably the bolt head screws off of Lebel and Berthier rifles. Vetterli Carcano front bands also don't seem to exist.

Jmoore, Yes, I would welcome more measurements. I eyeballed some of the drawing and I think it is close but would like to update the drawing with any input I get. Thx!

Aragorn, Yes, I think there is a market for these small parts. Wisner's in Washington makes a lot of small parts but not for milsurps. I personally don't feel the motivation to do it commercially but for the right peson it could work.

Thx, Salt Flat

Jmoore, I re-read your post. I think neasurements form one part would be enough, Please send me the numbers and I will update. THX, Salt Flat

Well, too late, I already started on another.

Partly because the first was a bit grungy and worn at the anti-rotation boss. Also because it's swivel hole (Index "B") goes all the way through. As does the next one. Additionally, now using a convertible digital caliper set that reads in metric and English units. Threads seem to be .8mm pitch or roughly 31tpi.

Entry one (not quite complete vis. threads)
M38 cal. 7,35

A 0.193 thread OD
B Wire diameter: 0.141"
C 0.264-0.267"
D 0.532-0.538"
E 0.082-0.084"
F 0.277-0.285"
G D-F
H 0.477"
I
J ~0.070"
K 0.262"
L 0.120-0.123"
M
N 0.046"

Transition radius from lug to outer face "E" 0.030-0.050" (Much smaller on the next sample forthcoming.)

Might I suggest either the innermost face or, preferably, the inner face of dimension "E" be the primary longitudinal datum? Dia "C" seems a good primary radial datum.

M38 6,5 cal.

A 0.192 .8mm thread pitch
B 0.144" wire diameter, through hole
C 0.260-0.264"
D 0.528"
E 0.078-0.083"
F 0.272"
G D-F
H 0.461-0.467"
I
J 0.090"
K 0.278"
L 0.095"
M
N 0.050"

Transition radius: 0.032" both sides

Subject to correction for lousy typing skills, bad handwriting, haste, and general stupidity.

Jmoore, Awesome work. I will update the drawing and we can review it before a final version. Thanks, Salt Flat

I've got at least one more. Given the variability in dimensions, a large sample pool seems in order.

Jmoore, The screw thread appears to to the metric M5 X 0.8. Salt tflat

Quote:

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Originally Posted by Salt Flat

Jmoore, The screw thread appears to to the metric M5 X 0.8. Salt tflat

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That would be my supposition as well. What's odd is that the slightly under 5mm dimension carries on through to the unthreaded shank as well.

Another entry:
"AA" S/N prefix, M38 6,5mm

A 0.192" Thread OD 0,8mm pitch
B 0.142" Wire diameter, through hole. No Non-through hole examples so far on my end! See supplemental data at end of list
C 0.261", but in drop "J" area: 0.274"
D 0.536"
E 0.0.73" & 0.079" (E1 and E2 indices?)
F 0.290"
G D-F
H 0.452-0.460"
I
J 0.095"
K 0.280"
L ~0.120"
M
N 0.043"
Transition radii: 0.00" & ~0.02"

Supplemental data: Band Screw tip (swivel retention extention past threads): 0.110" OD X 0.140" length.

Really, no more entries from other folk? This is probably the best request for dimensional info ever presented on this site! Salt Flat's done the hard part. All we have to do is plug in numbers.

M38 Carcano Lower Band Swiivel Stud Drawing REV A. These are the final dimensions. Salt Flat

Most excellent!

Could start files on other parts as well if folk provide some feedback/submissions. Strangely quiet thread. Maybe it just needs time.

I made up one of the band swivel studs as shown in the drawing. Someone down the road may be motivated to make one, so I have posted a picture sequence that is pretty self explanatory. I just used a scrap ½ inch bolt for stock and left it long so it could be held in the lathe and vise. It is much easier to buy one than making one but if you like to make things, go for it! Salt Flat

Looks better than most originals!

Nice job Salt Flat!

How did you leave/create the anti-rotation triangle?

BT

Great work & thread.

Beartracks and HOH Thanks! The anti rotation triangle was created by turning a shoulder on the piece the right depth and diameter to contain the feature. Then I used some machinist blue layout dye and marked the location of the triangle sides with some scribe lines. Then I used use a small hacksaw and files to remove the excess material. I make some "safe" files up by grinding the teeth off one of the edges so you can better control where you want to remove material from the workpiece. It helps to have the band there to continually check the progress. Once the nub will slip into the band you're done! All this makes me really appreciate what the earlly gunmakers accomplished all by hand! Salt Flat

Machinist magic!

Thanks for the explanation Salt Flat. Funny how those little details can cause a lot of extra work!

BT

A guy is making them new since originals are no longer available. I bought one and it fit perfectly, couldn't be happier!

He goes by allibaba34 on ebay. has one listed right now for $9.75 with free shipping.


BT

Nice to hear they fit since I just bought one from him on Ebay. For some reason I paid more on Buy Now auction, but happy to have a missing piece for new M38 almost in captivity.

Yes, its nice to find someone making these. As you can see 10 months had gone by and I still hadn't started working on making one. For the money, most of us don't have Salt Flat's skills or patience to get the job done, especially for the price this fellow is charging. Mine fit very well, and the blued finish was nice.

I should mention we actually shot the M38 today. The one remaining issue we had besides the stud was some horrendous tool marks in the chamber that prevented extraction (brass would flow into the tool marks). I got them honed out by using a .308 chamber hone. We ran a full clip of 6 rounds of Prvi through it. Really nice shooting little rifles!

Enjoy,
BT