Bullneck frame machining

[Steve Little]

As mentioned in another thread, I still have all the machining fixtures from the RFE frame business.
A young guy recently asked me if I would machine all the tubing out of his wrecked Bull neck frame to get it in readiness for re-tubing.
I think I am at the level of doing too much posting on the forum so I'll put it out there for consensus. Pictures-descriptions? Yes No?

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[Rubone]

No such thing as too much posting Steve, go for it!!

[Rooster]

Absolutely!!

[hairynob24]

this is good learning Steve ,yes from me

[painterdale]

Agree with all of the above. Keep it comin', Steve!

Dale

[pan620]

Please do!

[Steve Little]

Thanks to all. Must be a self imposed restriction ... or mind chatter.

When a fixture is made, usually a Datum point will be machined into it.
Machinists use the Datum to align the fixture to the measuring equipment of the machine, and all measurements are referenced from this point. Probably ho-hum info for the machinists in the club, but might be interesting and have some educational value for others.
Usually a machinist will have a booklet or diagram for each fixture and this will have a list of tooling, machining procedures, and measurements.

The datum on this fixture is the center drill mark in the top edge.

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I haven't used this fixture for a year and the booklet is not with the others.
While I have a fossick around and look for it.
Feel free to talk among yourselves and there is tea, coffee, and biscuits on the back table and I'll be back shortly.

[nuklhd]

Steve, this certainly isn't ho-hum stuff for me. all of this will be new to me and a blast to follow along.

[Steve Little]

Thanks nklhd.
Good to see you on board.

A tense ¾ of an hour went by before I located the machining book under a box.
Once I found it, I moved the table to the appropriate side shifts and could get on with drilling and milling out the down tubes.
Fitted to the neck into the fixture, and a 1” drill took out the stiffener brace.
This has to be done, as I use a 6 flute 1-1/8” end mill to finish the clean up and they are not designed to take out a lot of steel.


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Cleaned out the stiffener and I got it nicely on center going by the witness mark in the bottom of the drill bore. I stopped at this point to take a picture. Completed the cut all the way to the bottom after that.

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The neck had some road trauma and the neck casting didn't get off scott free.

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[Steve Little]

Yep I'm happy with that. That sliver of steel down the bottom is probably a couple of thou” thick.

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7.30 pm and being hailed for dinner. Time for lights out.

[Rooster]

Thanks so much for the play-by-play, Steve! Wonderful stuff for a non-machinist like me.

[Steve Little]

Thanks Rooster.
Do you play with frames as well?

Same process for the other side.

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[Steve Little]

View from the other side of the hole.

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Yep. I like that one as well.
That is my job on the neck complete. The customer is going to splice a new backbone onto the remaining section.
Time to remove this fixture and do a quick clean up around the mill. I don't like swarf underfoot.
When I've got it clean, I will set up the next fixture for the next forging.

[Rooster]

Thanks for today's batch of photos. Steve.
And Yes, I've been known to dabble with repairs to the most common issues seen on knuckle and pan frames. But nothing on the level you display.

[hairynob24]

Steve away nice to see you at your craft ,i will show my son this thread ,he has more knowledge than i with what you are doing and will learn from what you put up here , young fellas need and want to learn this type of work and this is as good as anywhere to learn ,as you know there arent any tech course available to teach what knowledge you have on frame building ,there are more and more young ones wanting to know how, we know your talent in this field ,cheers Rob