Thread: Help please Welding a bolt to my table saw - height winder threads have stripped

Pics here on partner site: Dewalt DWE7491-XE - Crank will turn freely upwards but blade will not rise

I'd like to weld a matching thread nut for the bolt just above the stripped threads housing.

Can it be done? i.e. weld a nut to that housing. I don't know what the housing is made of.

If so:

What type of material for the bolt should I get?

Any takers in the Glen Iris/East Melbourne area?

Thanks in advance.

Originally Posted by barrysumpter

Pics here on partner site: Dewalt DWE7491-XE - Crank will turn freely upwards but blade will not rise

I'd like to weld a matching thread nut for the bolt just above the stripped threads housing.

Can it be done? i.e. weld a nut to that housing. I don't know what the housing is made of.

If so:

What type of material for the bolt should I get?

Any takers in the Glen Iris/East Melbourne area?

Thanks in advance.

That looks like cast iron and welding would be very difficult in that position.
I can think of a few ways of fixing it, but it is a bit hard to say without seeing it in the flesh so to speak.
I am obviously too far away to do much for you, but I'm sure someone closer should be able to help out.

Should I waste my time tracking down a m14 nut?
If so, any suggestions on what material?
stainless, black, brass, etc.

Originally Posted by barrysumpter

Should I waste my time tracking down a m14 nut?
If so, any suggestions on what material?
stainless, black, brass, etc.

If that thread was M14 x 1.25 then plenty of garages will have the ability to put a helicoil in it since that is a standard spark plug size. If it is M14 x 1.5 its going to cost you $100 for a helicoil kit so maybe not worth going that way.

I would suggest the easiest way to fix that is to tap the appropriate sized thread into a piece of plate somewhere between 8 and 12mm thick, and then bolt it onto the top or bottom of the casting (top or bottom depends on which side the nut plate will be pushed against the casting). Shape the nut plate to provide as much contact area as possible.

tapping.jpg

Michael

You can find cheaper helicoil kits than that if you look around. https://www.ebay.com.au/itm/METRIC-T...frcectupt=true

Originally Posted by lamestllama

If that thread was M14 x 1.25 then plenty of garages will have the ability to put a helicoil in it since that is a standard spark plug size. If it is M14 x 1.5 its going to cost you $100 for a helicoil kit so maybe not worth going that way.

Looks like plenty of room.

But not a welder.

Don't know if spot welding would work on this material or not.
Or whether it would be easier or not.

TIG welder?



IMG_2746.jpg

IMG_2754.jpg

IMG_2755.jpg

With the helicoil kit,
would I have to widen the thread hole to say 16mm
Then insert a 2mm collet that has a 14mm / 2mm thread?

I was thinking screw the 14mm nut onto the bolt.
Insert the the bolt into the stripped thread hole.
lock everything down on the bolt top and bottom.
Then spot weld the nut onto the gear housing.

Any further thoughts?

Originally Posted by barrysumpter

Looks like plenty of room.

But not a welder.

TIG welder?

Those bits are die cast. They might be Aluminium or they could be a zinc alloy. If Al it could be welded with TIG (or MIG) but if it is zinc alloy it won't weld nicely. Welding will also mean that the material will need to be the same as what is already there.

On the other hand, if you used a helicoil, that would put a thread of stainless in there. If you used an external nut like pictured above, it would be steel and plenty strong as well.

The helicoil option will work but as well as buying the insert you will also need to obtain (buy) the tap and an appropriate sized drill. Not necessarily cheap.

Michael

PS. Spot welding is possible in theory but to weld to that, not practical - too much power required.

That housing appears to be a cast aluminium, the easiest way to fix it would be using a Helicoil. If you tried welding it, you'd probably have a pile of scrapmetal. To fit a Helicoil (which is a registered product name) the hole would need to be tapped for the size supplied in the kit, no need to drill it out, then a diamond shaped coil is screwed in to the depth required, and the driving tang broken off.
I think someone mentioned it was a Spark Plug size, so try ringing local Cylinder Head Reconditioners, you may have to go a bit wider on your search, as they may be a bit further away than just down the street.
HTH
Kryn

Originally Posted by Com_VC

You can find cheaper helicoil kits than that if you look around. https://www.ebay.com.au/itm/METRIC-T...frcectupt=true

That is good to know. You don't use these things often but at that price it is a very economical fix.

Thanks gents.

Since the weld probably won't work on this material,
as advised I'll have to go with the Helicoil.

Much appreciated.

Just make sure you get the right one to suit the thread you have there. You 100% sure it is metric?

Hi Barry,
if your thread IS M14 x 2 helicoils are scarce in that pitch,even on E bay,

I found this but it was expensive to me. Just under $50.

https://www.ebay.com.au/itm/METRIC-T...r=600443080132

You need to scroll through and select the correct size and pitch.

Given you have to drill for the tap(both supplied) be aware that if its in situ,will you have room to fit and manipulate the electric drill which you will need to use?

Grahame

The bottom tip was m12 using a number of Bunnings bolts.
The m16 was too big.
they didn't stock in between.

So asked the Bunnings tool shop to use caliper to get about a 14mm width.
On returning home used my callipers and magnifying headset to measure the thread at 2mm.

He mentioned he had experience with a metric on one end of a rod and imperial on the other.
Surely not Dewalt! LOL!

Too much traffic by the time I found a place that did have m14 1.5 and 2mm threads.
after taking things apart and finding the issue and researching repair centres trying to get an estimate trying to explain what I needed.
Turn around time wasn't offered but 10 days wait to get to the repair had me sorting it out myself.

Was planning on going to Metro Bolts (anyway) in Melb - 12 mins away out of rush hour tomorrow to be sure.

Then select the heli-coil based on my findings.
Hoping Metro Bolts will have the help-coil I need.