OAG mounting difficulity to flattener/reducer

astrom

I have a Stellavue reducer/flattener SFFR102T, an adapter ring M42 to M48, and an OAG. I removed the guider prism, assemble the reducer/flattener to the adapter ring to the OAG without the prism. I cannot insert the prism because the adapter ring/reducer/flattener block the insertion of the guider prism. The threads of the reducer/flattener cover the guider prism slot. What do I do now?

Sam@ZWO

you can add some spacer if the threads of your reducer is too long