8” Bison Chuck Female Mounting Holes

[erikmannie]

I have an older Bison 8” 3 jaw chuck that requires 6 mounting bolts.

I went to the hardware store, and 3/8-16 does thread in okay, but I have a hard time believing that a *Polish* chuck would ever call for Imperial hardware.

I gather that M10-1.50 is almost the same as 3/8-16, but the local hardware store does not carry M10-1.50.

Do any of you know if Bison chucks have metric or Imperial female mounting holes?

I know that I *could* use the 3/8-16 bolts, & I have a 3/18-16 tap that I could run through the female mounting hole. Does anybody have an opinion on whether or not running a 3/8-16 tap through what could be an M10-1.50 female hole might spoil the chuck?

Note that 3/8-16 would be M9.525-1.5875 (compare to M10-1.50).

Some Googling on my part indicates that a 3/8-16 can thread in to an M10-1.50 nut (“it is loose enough & it fits”), but a 3/8-16 nut will not thread on to an M10-1.50 bolt (“too tight”).

 

[erikmannie]

If Googling directly for the bolt (for an 8” chuck) one finds both sizes offered:

 

[stupoty]

Do you mean the bolts that hold it to the back plate?

My "period" 8 inch bison , the bolts were pulling it off register due to being to toght in the holes, I turnes the cap head screws down a bit to give them some breathing room. (The cap head part)

Stu

 

[mmcmdl]

Curious as to why a bolt cost $13 or am I reading this cross eyed ?

 

[WobblyHand]

You can buy 10 for that price. But try using a thread gauge to determine the pitch. Should be able to fit one into a 3/8" hole.

If you don't have a thread gauge, in my opinion you should get one. Both imperial and metric. Or, lacking that, single point a couple rods to those threads to try them. Won't take very long to make the threads. Better than buying hardware you don't need.

 

[erikmannie]

Do you mean the bolts that hold it to the back plate?

My "period" 8 inch bison , the bolts were pulling it off register due to being to toght in the holes, I turnes the cap head screws down a bit to give them some breathing room. (The cap head part)

Stu

These are the 6 female holes in the rear of the chuck. 6 bolts passing through a backing plate would thread into these holes.

The application for which I am using this chuck does not call for a backing plate. The chuck will be bolted on to a welding positioner (rollout wheel). As such, I will be looking for (flanged) hex head bolts.

 

[erikmannie]

@mmcmdl

Hopefully for that price you would get a set of 6 bolts drop shipped from the Bison distributor!

 

[erikmannie]

You can buy 10 for that price. But try using a thread gauge to determine the pitch. Should be able to fit one into a 3/8" hole.

If you don't have a thread gauge, in my opinion you should get one. Both imperial and metric. Or, lacking that, single point a couple rods to those threads to try them. Won't take very long to make the threads. Better than buying hardware you don't need.

I have many thread pitch gauges. I will try to fit one in there tonight. Great idea.

It will be interesting to see if one can tell the difference between 16 tpi and 1.50.

 

[erikmannie]

I still wonder if Bison has ever used Imperial hardware on any of their chucks.

As they are manufactured in Poland, I would think that the Bison engineers would work exclusively in metric.

 

[erikmannie]

Because I am bolting the chuck to a rollout wheel, I will buy a hex head or flanged hex head in either Grade 8, 10.9 or 12.9.

As far as running a tap in there, the chuck is almost certainly either grey cast iron or ductile cast iron (I have machined this chuck a fair amount). I haven’t measured the depth yet, but the female hole is surprisingly deep.

I have gotten into the habit of purposely buying bolts that are too long, & then using a lathe to shorten them down to exactly the length that I need. This is so easy to do with a 5C collet (chuck).