Author Topic: Helicoil inserts  (Read 1102 times)

Offline BSA Biker

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Helicoil inserts
« on: 28.12. 2017 20:23 »
  Hi all,
the last time I removed the front tappet cover from my 1960 A7SS, one of the stud bolts came out together with a small strip of aluminium attached to the threads, oh dear.  *sad2*

As this will need to be helicoiled to get it fitting again, can somebody please tell me what the lower stud bolt thread is please, that way I can purchase the correct kit. While you are at it please tell me and the people who make the replacement special "extended" nuts what the top thread is as well, over the years I've bought numerous (in sets of four X 2) incorrect threaded ones in stainless steel to replace my old rusted ones. This is probably why the stud bolt was damaging the aluminium thread in the first place, from when I tried to fit these useless expensive things. Normally bought at auto jumbles where the seller is never seen again!.  *eek*

Is it an easy operation to fit a helicoil, all the engineers out there please don't laugh I was trained as a civil engineer, not a mechanical one.  *conf*

Online JulianS

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Re: Helicoil inserts
« Reply #1 on: 28.12. 2017 21:01 »
The thread is 1/4 BSW x 20 tpi. The nut thread is 1/4 x 26 tpi Cycle (1/4 BSF also fits)

The extended or shouldered tappet cover nuts (part 65 2153) were used on pre GA7 framed bikes, the 1960 on used a nut (01 6032) with a small deep hex (takes 2ba spanner). These were not shouldered.

You might find a rocker box with good threads on ebay at a similar price to a thread insert kit.

Offline BSA Biker

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Re: Helicoil inserts
« Reply #2 on: 28.12. 2017 21:45 »
Thank you for the info Julian,   a long time ago my bike had those type of nuts, Polly Palmer of BriTie, back in 1990 or so rebuilt the engine for me and "lost" the original ones, as I bought it in 1967, when he told me that the extended tappet cover nuts were the correct type I believed him. Plus over the years I have never seen the ordinary nuts on any model, or at the auto jumble stores. I did however purchase these type from Draganfly last year, unfortunately these were the incorrect thread, probably a metric one.

The cost of buying and posting a rocker box etc would be expensive being sent to Spain, the helicoil route will be easier, plus I may need more inserts in the future.

Online morris

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Re: Helicoil inserts
« Reply #3 on: 28.12. 2017 21:49 »
Is it an easy operation to fit a helicoil
It ain't complicated. Just make sure to drill and tap the hole at a perfect 90° angle.
If the stud points sideways you'll have trouble getting the cover on.
Buying a set isn't a waist of money because the timing and primary cover bolts are the same size. Sooner or later you'll probably need to do one of them to.
There's several manufacturers. I get mine from Volkel. http://www.voelkel.com/en/
The set contains a drill, tap, coil inserter, a tang breaker and 20 inserts and costs about €35
The dimension you'll need is 1/4 BSW X 1d. The 1d stands for it's length (1x diameter so that makes them 1/4" long). 2d would be to long I think.
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Offline BSA Biker

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Re: Helicoil inserts
« Reply #4 on: 28.12. 2017 21:55 »
Thanks for even more info Morris,

when we get into the new year I will contact the company you mentioned and order some, you read my mind about the other uses for them. *smile*

Online Rex

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Re: Helicoil inserts
« Reply #5 on: 28.12. 2017 22:33 »
unfortunately these were the incorrect thread, probably a metric one.

I seriously doubt that Draganfly would commission a load of metric nuts for this application as they never would fit. Someone mentioned above that 1/4 BSF is the same as 1//4 BSCY; sometimes they can successfully interchange and sometimes (due to poor manufacturing tolerances, unworn new threads etc ) they won't fit at all.
Maybe you have this situation?

Online muskrat

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Re: Helicoil inserts
« Reply #6 on: 29.12. 2017 01:14 »
G'day BSA Biker.
To add to previous posts. If your real careful you won't need to drill. The tap will take with a little pressure.
I say this as (done it numerous times) drilling and tapping gives you twice as much chance of getting it off angle, also may be able to do it without removing the box ((we all hate that) top rear is hardest).
Cheers
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Offline Tomcat

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Re: Helicoil inserts
« Reply #7 on: 29.12. 2017 05:58 »
Perhaps you could do a practice run in a bit of scrap alloy? Better to waste a helicoil than a rocker box! As Morris says be sure to drill at 90 degrees.
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Online RichardL

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Re: Helicoil inserts
« Reply #8 on: 29.12. 2017 13:07 »
It ain't complicated. Just make sure to drill and tap the hole at a perfect 90° angle.

This point slips easily from the tongue, but much less easily from the workbench of a casual mechanic. Yes, the tables on even cheap drill presses rotate, but clamping and alignment in 3D is bound to be tricky on this surface with no parallel or perpendicular surface for reference.

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Offline BSA Biker

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Re: Helicoil inserts
« Reply #9 on: 29.12. 2017 15:34 »
Well once again thank you for all your help/information, I must admit that now I'm rather concerned about fitting the Helicoil insert, but Muskrats method appeals to me. I'm not in any hurry to fiddle about with my pushrod positioning tool etc, having taken the rocker box off and then putting it back on.

Rex, your mention of the use of 1/4"BSF makes sense, but whatever the thread was it just didn't go on beyond the first pickup, not even close. When mentioned to Draganfly, who did buy up a lot of stock from "the stainless steel man" who used to go to various auto jumbles back in the nineties, they offered to refund the cost of them if they were sent back. That unfortunately would've cost more in postage from Spain, so I didn't bother, just threw them in a box with other badly fitting so called BS cycle threaded products (26TPI), mostly in S.S. some from the chap mentioned earlier.

Online Greybeard

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Re: Helicoil inserts
« Reply #10 on: 29.12. 2017 15:47 »
Lightning Spares - Spit! *bash*

Offline BSA_54A10

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Re: Helicoil inserts
« Reply #11 on: 05.01. 2018 09:02 »
G'day BSA Biker.
To add to previous posts. If your real careful you won't need to drill. The tap will take with a little pressure.
I say this as (done it numerous times) drilling and tapping gives you twice as much chance of getting it off angle, also may be able to do it without removing the box ((we all hate that) top rear is hardest).
Cheers
Helicoils are a sloppy fit at the best of times so do not let it worry you.
Take a close look at the helicoil then thread a bolt into it and see how badly it fits.
Regardless of the thread angle they all are made from the same wire.

FWIW I generally load the tap into the battery drill & use the same method as Musky for any hole smaller than 3/8".
Near enough is good enough, it is a through bolt so slightly off line will not matter.

The exception to this is if you are fitting extra long helicoils but the std ones only have a small number of turns of thread
Bike Beesa
Trevor

Offline coater87

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Re: Helicoil inserts
« Reply #12 on: 07.01. 2018 01:38 »
 At work the three times diameter inserts are always ordered from grainger. You can clip the number of coils you dont need off a new insert, that way you can get the maximum number of new threads possible.

 I know they are a little more pricey, but its not like we install that many inserts. Hopefully.

 Lee
Central Wisconsin in the U.S.

Offline BSA_54A10

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Re: Helicoil inserts
« Reply #13 on: 07.01. 2018 08:36 »
I used to always measure the number of threads , subtract 2 ( 1 each top & bottom ) for clearence and then trim a longer helicoil to fit.
However most of the places they go is in thin alloy and the std 1 x dia is oft too long.
So I gave up on the long ones.
Yet to have one pull the threads of the hole so looks like 1 x d is fine for most cases.

The  disclaimer is plug holes, they get solid inserts as do the sump stud holes as they  need to be really oil tight and helicoils are not because the thread shape is not the same as the shape of the fastener.
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Trevor

Offline TT John

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Re: Helicoil inserts
« Reply #14 on: 08.01. 2018 13:53 »
In ally I try to maintain the old thread by using HTS 2000, it's similar to lumiweld but better, I just stand a stud with the same thread in the hole, after cleaning it up, then melt the HTS 2000 around it, after it has cooled the screw can then be unscrewed to leave the job perfect. It is expensive to buy initially but worth it, take a look at the demo of the product on line before you buy.

Kind regards TTJohn