Where to have a gear wheel made.

[cheb]

This is from the Perrin jig borer and is the reason the rise and fall needed looking at.

Firstly, I don't think the head is a Perrin. The base is, it has a name on it. The cross table looks similar to the Perrin on lathes.co.uk. The head? The column looks home made, welded steel plates and the base has been burner cut and not dressed back to completely smooth. The controls on the head are similar in look to the Perrins but there's detail differences, non rotating handwheel knobs, different font and style for the measurements, and the like.

It'd possibly take too long to identify the make of the head so I'd like to get the gear pictured below copied. I'm happy to pay for it, I don't need mate's rates, but a guide price would be useful if anyone on here can do it. Failing that, recommendations please.

Also, I make no complaint about the machine being mislabelled.

 

[Pete.]

Looks like a multi-start worm wheel that's been hardened and ground. Someone could probably reproduce it but it would be turned and in un-hardened stock.

 

[Agroshield]

If it is only chipped, your most economic option might be brazing it up and filing it back to shape. Done well, it will outlast you.

 

[Brad93]

There’s a company in Basildon that could knock that out but I’ve never used them, friends have told me about them.

 

[frank horton]

Cheb,
the hardest part of that job is getting somebody to make JUST 1 i'm afraid.....
had something similar, could get a min of 50 made in the end just sold the machine.....just got fed up with months of trying....
just keep trawling Google.....

 

[cheb]

It's a triple start thread :fun: Thanks for the replies. I might start with brazing as I can get it done locally and it'll not make it worse.

Another option is to make a different rise and fall system for it. I'll ponder on the options as I reassemble the rest of it.

 

[cheb]

I found the broken off piece inside the gearbox:

Brazing seems like the easiest option, assuming if it could be built up with braze then the bit can be brazed back on.

 

[Kram]

Looks like 12mm or 1/2" pitch, 4mm lead. Do you know what thread/gear form, or what is the gear it drives?

I can see the root has a step, is that just extra clearance from the grinding wheel?

I am happy to try. If the correct thread insert is available then making a multi start cant be too difficult

 

[Seadog]

Here's my one and only attempt at making a worm. It's single start and was cut with a hand-ground tool - 29° B&S form. It was for a rotary table that had a knackered one and was made as a test to see if I could do it. It was so good, despite the little faux pas on the left hand side (which is never in contact), that I decided to use it for the repair. Just a piece of unhardened silver steel.

A three-start will be more of a challenge because of the extreme side-relief that needs to be ground onto the tool.

It'll be six years old in two week's time, and I've never used it

 

[Gareth0123]

5 or 6 years ago I had a replacement worm gear for my 8"Ø Sealey cold cut saw made for me by HPC Gears It wasn't expensive, was a fraction of the £150+VAT + P&P that sealey wanted.
On arrival the new worm looked and felt to be better quality than the original and it did at least 75,000 cuts in various sizes of M/S bar for me before I sold the saw on (its still going strong for a local associate) and HPC even returned the broken worm gear back to me.

 

[Pete.]

Looks like 12mm or 1/2" pitch, 4mm lead. Do you know what thread/gear form, or what is the gear it drives?

I can see the root has a step, is that just extra clearance from the grinding wheel?

I am happy to try. If the correct thread insert is available then making a multi start cant be too difficult

You got that backwards. Pitch can never be greater than lead.

 

[brightspark]

clean it up and silver solder the piece back in and file smooth

 

[armalites]

These people may be able to help.

https://www.hewitt-topham.co.uk/

 

[bricol]

Although I guess if you ring them, you will hear "Renown Gears" on the other end

https://www.renowngears.co.uk/about-us/company-history/

They do know their stuff, are usually busy, make a quality product. Main man is current chair of the British Gear Association.

Been doing some cracking design, test (in conjunction with Newcastle Uni Gear/Design Unit) and manufacture of some rather expensive gears for my one tonne hypocyclic gear box project - tell 'em Brian at CMB sent you - and it won't make a blind bit of difference

 

[graffian]

I have the bronze to make a new worm for a bike motor, the oil pumps is worm driven.
I got as far as working out I can cut a worm with a 1/3rd of a tenth error on pitch with
gears I have. Haven't cut one before but it looks like a thread to me.
What DP is the gear?

 

[Seadog]

Haven't cut one before but it looks like a thread to me.

Which is exactly what it is.

 

[cheb]

After reassembling and testing the gearbox I decided to do something different, a leadscrew and nut between the column and head, where the rack used to be.

HPC were very helpful, both about the gear and also the leadscrew parts. An order has been placed.