Pan cover screws

ratchet449mc
Member
Posts: 25
Joined: Mon Jun 22, 2015 1:33 am
Bikes: Frankenstein Panhead - pan motor shovel chassis....
Has thanked: 13 times
Been thanked: 1 time

Re: Pan cover screws

#16

Post by ratchet449mc »

Thanks for the great input, folks... Interesting tidbits, like the thread form difference of 55 Degrees as opposed to 60. Don told me a 3/16 would be a loose fit in a 10-24 thread, but I would need to run a 10-24 tap through the new holes since he redid them to 3/16-24.. Makes sense now...
awander
Senior Member
Posts: 2082
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 163 times
Been thanked: 511 times

Re: Pan cover screws

#17

Post by awander »

ratchet449mc wrote:Thanks for the great input, folks... Interesting tidbits, like the thread form difference of 55 Degrees as opposed to 60. Don told me a 3/16 would be a loose fit in a 10-24 thread, but I would need to run a 10-24 tap through the new holes since he redid them to 3/16-24.. Makes sense now...
Now I'm really confused-If you're going to run a 10-24 tap through the holes, then why not use 10-24 screws(which might very well fit even if you didn't run the tap through them)?
RUBONE
Moderator
Senior Member
Posts: 8378
Joined: Sat Nov 15, 2008 4:09 am
Bikes: Multiple H-D, Ducati, BMW, Triumph, BSA,...
Has thanked: 478 times
Been thanked: 2933 times

Re: Pan cover screws

#18

Post by RUBONE »

like the thread form difference of 55 Degrees as opposed to 60.
3/16-24 USS threads are NOT a different threadform than 10-24. But BSW are. Don't confuse the two.
awander
Senior Member
Posts: 2082
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 163 times
Been thanked: 511 times

Re: Pan cover screws

#19

Post by awander »

RUBONE wrote:
like the thread form difference of 55 Degrees as opposed to 60.
#/16-24 US threads are NOT a different threadform than 10-24. But BSW are. Don't confuse the two.
Robbie means 3/16-24 US threads....and he's right!

Just because 3/16-24BSW exists, and 3/16-24 doesn't appear in the Machinery's Handbook as a US thread-it is highly unlikely a BSW thread of any kind was ever used on a Harley.
ratchet449mc
Member
Posts: 25
Joined: Mon Jun 22, 2015 1:33 am
Bikes: Frankenstein Panhead - pan motor shovel chassis....
Has thanked: 13 times
Been thanked: 1 time

Re: Pan cover screws

#20

Post by ratchet449mc »

Ok, I get what you're saying, but I never said I was going to go with 10-24 screws..Nor did I say I was planning on using BSW 3/16-24"s either..I'm just looking for the skinny on getting the right thread screws in a allen head version. Sorry if I confused anyone...Think I'll call Don and see what he knows...Really appreciate everyone trying to help.. It amazes me how many little things about the old iron can be lost in time..
That alone makes this site so valuable.. One of the reasons I don't want to mess with 10-24's is I may sell the heads and want them just as I got them after Don did his magic on them...
awander
Senior Member
Posts: 2082
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 163 times
Been thanked: 511 times

Re: Pan cover screws

#21

Post by awander »

ratchet449mc wrote:Ok, I get what you're saying, but I never said I was going to go with 10-24 screws..Nor did I say I was planning on using BSW 3/16-24"s either..I'm just looking for the skinny on getting the right thread screws in a allen head version. Sorry if I confused anyone...Think I'll call Don and see what he knows...Really appreciate everyone trying to help.. It amazes me how many little things about the old iron can be lost in time..
That alone makes this site so valuable.. One of the reasons I don't want to mess with 10-24's is I may sell the heads and want them just as I got them after Don did his magic on them...
Why not just try the 10-24s? They will almost certainly fit.
Bigincher
Former member
Senior Member
Posts: 2784
Joined: Tue Dec 18, 2007 2:10 pm
Bikes: 1941/59 EL
1952 FL
1977 FLH
1994 Fatboy
Has thanked: 22 times
Been thanked: 110 times

Re: Pan cover screws

#22

Post by Bigincher »

Please let us know what Don says so we can put this matter to rest.
Excalibur
Senior Member
Posts: 882
Joined: Mon Jul 27, 2015 1:01 pm
Bikes: '61 Pan
'83 FXWG
'74 T150
'41 Indian, '29Norton
'25 HD
'13 JAP
'12 BSA,
'11&'12 NH
'08 Triumph
Location: NZ
Has thanked: 505 times
Been thanked: 361 times

Re: Pan cover screws

#23

Post by Excalibur »

3/16 BSW does work with 10-24 screws or at least it did on my STD heads. When I got the heads, these threads weren't finished completely as though the machinist didn't use a bottoming tap.
I needed to deepen the threads at the bottom of each hole. I must have over 200 taps but not a 10-24! I asked around and was able to borrow one from a friend. It was from a large set and had never been used. I was surprised to find the tap would not cut the threads. The further I wound the tap in, the tighter it got! The tap, while it looked nice was made of carbon steel from Japan. I had a HSS 3/16 BSW tap and I pondered over using it. I'd just spent a small fortune on these new heads so I was hesitant. I thought about for a day or so. Then I decided to test drill and tap holes in scrap ally. I could not fault the test so I went ahead. The HSS tap cut perfectly where the other tap simply refused. Admittedly I've seen problems in the past with those cheap carbon steel taps so I've always avoided them. I didn't think I'd have an issue with cutting aluminum although the STD head material is very high quality alloy.
Hope this helps.
awander
Senior Member
Posts: 2082
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 163 times
Been thanked: 511 times

Re: Pan cover screws

#24

Post by awander »

Excalibur wrote:3/16 BSW does work with 10-24 screws or at least it did on my STD heads. When I got the heads, these threads weren't finished completely as though the machinist didn't use a bottoming tap.
I needed to deepen the threads at the bottom of each hole. I must have over 200 taps but not a 10-24! I asked around and was able to borrow one from a friend. It was from a large set and had never been used. I was surprised to find the tap would not cut the threads. The further I wound the tap in, the tighter it got! The tap, while it looked nice was made of carbon steel from Japan. I had a HSS 3/16 BSW tap and I pondered over using it. I'd just spent a small fortune on these new heads so I was hesitant. I thought about for a day or so. Then I decided to test drill and tap holes in scrap ally. I could not fault the test so I went ahead. The HSS tap cut perfectly where the other tap simply refused. Admittedly I've seen problems in the past with those cheap carbon steel taps so I've always avoided them. I didn't think I'd have an issue with cutting aluminum although the STD head material is very high quality alloy.
Hope this helps.
A BSW tap of the same nominal size, will cut a "bigger" internal thread than a US standard tap, because of the shallower thread angle, and also because of the rounded thread roots.
Buddhahoodvatoloco
Site sponsor
Site sponsor
Senior Member
Posts: 1916
Joined: Fri Jul 01, 2011 8:43 pm
Bikes: 1969 FLF
1937 EL
1940 U
Location: san diego
Has thanked: 1475 times
Been thanked: 241 times

Re: Pan cover screws

#25

Post by Buddhahoodvatoloco »

Andygears,
your summation of difference in thread bolt/screw for pan pans, is interesting, and does merit credibility.
Thanks for the mind %^ck..
El Buddha
ratchet449mc
Member
Posts: 25
Joined: Mon Jun 22, 2015 1:33 am
Bikes: Frankenstein Panhead - pan motor shovel chassis....
Has thanked: 13 times
Been thanked: 1 time

Re: Pan cover screws

#26

Post by ratchet449mc »

Ok... I talked to Don and what he expressed was the threads are 3/16-24 NF....He also said 10-24 screws will work, but will be tight...Apparently back then, Harley used Chandler fasteners which are no longer available...So, unless someone has a stash of them, it's on to 10-24 screws for me....Thanks, everyone for your input....
awander
Senior Member
Posts: 2082
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 163 times
Been thanked: 511 times

Re: Pan cover screws

#27

Post by awander »

Cool! I hope you get that thing together soon, and that it's everything you wanted it to be.


Just one note, Don was mistaken when he called it 3/16-24 NF. 3/16-24 is NOT a National Fine size.

The (obsolete) NF series included sizes 0-12, and 1/4"-3".

Neither the National Fine, nor the National Coarse, screw thread series included any 3/16" threads.

As noted previously, 10-24 would be the closest size, and this is a National Coarse or NC size, NOT NF.

The corresponding NF size is 10-32.


This doesn't really matter for this discussion, but I didn't want someone to find this in a search and get wrong info.
socalrider
Senior Member
Posts: 550
Joined: Sat Jun 14, 2008 5:22 am
Bikes: 1963 pankenstein ; 1965 flh ; 1978 shovelhead lowrider
Has thanked: 67 times
Been thanked: 128 times

Re: Pan cover screws

#28

Post by socalrider »

Andy, thanks for the great info! Always great learning something new that pertains to old American iron.
ratchet449mc
Member
Posts: 25
Joined: Mon Jun 22, 2015 1:33 am
Bikes: Frankenstein Panhead - pan motor shovel chassis....
Has thanked: 13 times
Been thanked: 1 time

Re: Pan cover screws

#29

Post by ratchet449mc »

Andy, What designation would 3/16-24 fall under? It doesn't seen that it would be a unified thread and it's not a coarse thread..Please pardon my ignorance here...Don and I were talking about oddball threads like 1/4-24 that HD used for the oil pumps...I just assumed 3/16-24 would be considered a fine thread.....Sorry...
awander
Senior Member
Posts: 2082
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH
Has thanked: 163 times
Been thanked: 511 times

Re: Pan cover screws

#30

Post by awander »

Hi Ratchet:

I haven't been able to find the 3/16 size in any standards documentation.

I have some other info that I can look through, and I'll let you know if I find it in any standard.

I know it was used, because I have a tap and a die for it!
Post Reply

Return to “Cylinderheads”