The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: BSA Biker on 28.12. 2017 20:23

Title: Helicoil inserts
Post by: BSA Biker 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*
Title: Re: Helicoil inserts
Post by: JulianS 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.
Title: Re: Helicoil inserts
Post by: BSA Biker 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.
Title: Re: Helicoil inserts
Post by: morris 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.
Title: Re: Helicoil inserts
Post by: BSA Biker 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*
Title: Re: Helicoil inserts
Post by: Rex 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?
Title: Re: Helicoil inserts
Post by: muskrat 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
Title: Re: Helicoil inserts
Post by: Tomcat 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.
Title: Re: Helicoil inserts
Post by: RichardL 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.

Richard L.
Title: Re: Helicoil inserts
Post by: BSA Biker 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.
Title: Re: Helicoil inserts
Post by: Greybeard on 29.12. 2017 15:47
Lightning Spares - Spit! *bash*
Title: Re: Helicoil inserts
Post by: BSA_54A10 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
Title: Re: Helicoil inserts
Post by: coater87 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
Title: Re: Helicoil inserts
Post by: BSA_54A10 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.
Title: Re: Helicoil inserts
Post by: TT John 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
Title: Re: Helicoil inserts
Post by: BSA Biker on 08.01. 2018 14:05
Well as usual getting things here in Spain can be difficult.  Sent an email to voekel in Germany, they passed it on to Novotools in Spain their distributors as they, and the Spanish one, do not deal direct with customers. Luckily the Spanish chap speaks English, my Spanish is poor to say the least, so at the moment I'm waiting for a reply to see where the nearest stockist is. Probably miles away from me, oh the joys of living in a large country with a small population compared to the UK, and cities far apart.
Title: Re: Helicoil inserts
Post by: groily on 08.01. 2018 17:42
Sounds a bit like France in that respect then  . . .

For thread inserts, I go direct either to Tracy Tools (most imperial stuff) or to Chronos the model engineering people (for BA stuff - but some sizes only).
They both supply happily to anywhere and it's probably quicker and cheaper to deal with them than go through some of the labyrinthine distribution chains of 'nearer' vendors.



Title: Re: Helicoil inserts
Post by: BSA Biker on 10.01. 2018 20:38
Hi Grolly,

Thanks for the info, ordered a repair kit yesterday afternoon from Tracy Tools, very helpful people.  The chap from Novatools in Spain has been equally as helpful but as their so called "local" supplier didn't even stock Voekel products, it would have probably taken longer to get than going to the UK, and I expect cheaper as well, even with UK postage. Local was 11/2 hours away.

 Is the runaround we get here in Spain Europe wide, yes I too have suffered in France in the past, it seems as soon as we are seen, never mind speak, they know that we are Brits and treat us appallingly because of it. Our Victorian ancestors have a lot to answer for with their superior attitudes, the rest of the world haven't forgotten it.
Title: Re: Helicoil inserts
Post by: groily on 13.01. 2018 17:47
Good question BSA Biker.

Best part of 20 years in 'Yrup' tells me the elements of a service economy that I got used to while living in the US of A, or before that in the UK, are quite hard to find.
It's not maybe surprising there are hassles with imperial bits and bobs as there is such a small market. BUT it amazes me it is easier and FAR cheaper to obtain, eg, old series metric threading tackle from the likes of Tracy Tools than it is from here, where the stuff was invented!

I never try to get any British m/cycle parts here, ever. And parts for other machinery are also usually far easier to get, and better-priced, from the UK or the US.

Not sure how other European countries rate. I've had great service from Hungary on occasion, always first-class from Switzerland as you'd expect, and good also from Germany and Austria. I wouldn't swap where I live, no way - but it is frustrating sometimes. Luckily, as an English speaker, with the www at the tips of the fingers, it's not so hard. But for my mono-lingual French friends, restricted to what they can find on the internet in French or with Google Translate, it's harder. Especially for the very many of them who aren't yet used to concepts like PayPal, online payments and banking transactions.

Even within the so-called 'developed' world there are massive differences in approaches to commerce it seems. One hesitates to make any comments about who's ahead and who's behind, but where I am reminds me of 20 years ago, with the exception of having now-reasonable (ie non-dial-up!) internet speeds! All very charming - until you need something!

It's not because we're furriners though I don't think, or not here anyway - it's just a cultural thing maybe.

Title: Re: Helicoil inserts
Post by: BSA Biker on 14.01. 2018 13:43
Hi again Grolly (Bill),

You saying about the area you live in being 20 years behind us, well when we first came over to the rural part of Catalunya, we thought that it was like the Britain I remembered from the 1960's at least fifty years behind us. Except for modern mobile phones etc, but it was the peoples attitudes that were the same as us from that time long ago, however the people who live in Tarragona, ones I've met that is, are like most city dwellers, they think that they are superior to villagers who they rate as peasants. This is unfortunate as these people are very helpful except for when my Spanish is bad and then they have no imagination about what I'm saying unless its pronounced perfectly.
As my house is a masia built on an olive grove Postman Pedro will not deliver direct so I have a Post Office Box in a local town, so maybe by Tuesday when I make my weekly visit the helicoil kit will be there. This is normal in Spain they only deliver to towns and villages, not to individual properties out in the sticks. Like you I do a lot of Amazon and UK orders as its easier that way to get the parts you need, my friend runs a car repair service and general DIY problems etc for most of the Brits in the area, so needless  to say his stuff comes from the UK. Oh the joys of living in the foreign, but who wants to go back to live in England now.
Title: Re: Helicoil inserts
Post by: Black Sheep on 14.01. 2018 13:57
Live in England? Tried it. Happy up here.